Accelerating Performance

Up On The Wheel

2012-01-06T10:32:00.000-08:00

Flying has always been on the list of things I would rather avoid. Of course, any dream destination becomes possible due to the miracle of modern flight. The travel aversion is derived from being in a cramped space that always seems to have the amenities a finger tip out of reach. Control is taken and as passengers, the drink cart is either too far away or bashing into the back of your already cramped elbow. Cocktail please!

While traveling from Seattle to Orlando for the 2011 Performance Racing Industry Tradeshow, I had a bucket load of time to experience the choices made by the engineers of the new Boeing 737 that was to carry us from point A to point B. Throw in the point C detour through New Jersey and internal debate time allowed me an eternity to wonder what engineers consider as the definition of “comfortable”. Plane engineers are forced to make compromises as their stock market driven corporations need to squeeze in extra seats striving for every penny that can pour into the profit column. The cramped space is an issue. But, the real problem is the loss of control. Somehow, my plane seat clarified my understanding that drivers must feel in control in order to win. I will say the plane engineers did a bang up job making sure the jet engines were attached securely to the wings.

My bonus Jersey Shore extended travel time provided ample opportunity for me to think about how to help drivers feel in control of their in car surroundings. Being bolted down to the seat like the Statue of Liberty on Ellis Island certainly defines a loss of control. Lady Liberty has been strapped down a long time – I hope she is happy with her position. Like airline travel, race driver amenities are predetermined and comfort choices are decided as soon as the belts are pulled tight and the engine roars to life.

The glare off my in flight TV was accentuated by the screaming 4 year old in front of me that made sure to shake the headrest TV screen straining my ability to absorb the commands of Captain Kirk yelling at Scotty that he needed “More Power”. Kirk must have been a crew chief in a former life. My poorly positioned in flight TV can easily be compared to gauges in a racecar. Mounting gauges so they can be seen at 150 MPH with an intuitive glance is a little more important that watching reruns of overly dramatic actors in Hollywood. Then again, drivers do sign autographs and smile for the camera while saying how much they love everyone. So, perhaps the red carpet at driver introductions is about the same as the content on American Idol where Ryan Seacrest waited in fear of the Simon ambush that came every week. The comparisons are endless – Bush race competitors attacking doctor’s makes for racing’s version of reality TV. Long live the “E” network.

All race team members are backyard engineers. Lucky teams are graced with college educated engineers. When building a car, are you just placing the gauges where they look good or are you considering the viewing angles and importance of each gauge?

Prioritizing gauge position is a choice that goes beyond centering them on the sheet metal dash.

An easy gauge mounting tip is to strap the driver’s helmet to the seat in race position. Needed safety devices prevent drivers from moving their heads from side to side. With the helmet strapped in place, tape a string to the center of the visor or tear off and tape the other string end to the dash. Place the dash side string where it runs straight from the helmet shield field of vision making sure the line of site is maintained throughout the steering radius. The most important gauge goes in the priority position and is located so a steering wheel spoke never blocks the drivers’ view of the gauge. Make sure the string stays straight through the turning path of the steering wheel. Follow the same routine with a second string for gauge 2 and mount the priority 2 gauge in a fashion that allows clear vision with an instant glance. If compromises must be made, make the required compromises on priority gauge 3 and 4. Running a string from the helmet location to the dash will show you, in advance, the line of site obstacles that you must overcome – and the string method can save you from drilling 2.5” holes in the wrong spot potentially destroying new sheet metal due to short cutting the planning process.

To keep your diver in control, switch panels need to be within easy reach. With the driver strapped in, all switches need to be ergonomically placed so the driver can instinctively activate all switches instantaneously. Red Flip Up Aircraft covers are mighty handy if your team is hit with the misfortune of a stuck throttle. Sudden losses of oil pressure benefits from a Flip Up switch cover potentially saving you thousands in repair costs. Even a 1/10th of a second time savings can save a pile of money if the driver can hit that switch cover quickly when the oil pressure drops. In the event of an on track mishap, ignition switches and start buttons need to be located for quick and natural operation. All switches need to be well marked. Often, drivers get into multiple types of cars and well marked switches are a must. Knowing, instinctively, the function of each switch falls in the safety category and mounting switches within easy reach is an area where compromise is a flagrant foul that is easily remedied by any backyard engineer.

Aircraft Switch Covers help drivers to instantly turn off their cars in the event of a stuck throttle or sudden loss of oil pressure. Easy access can save equipment and improves safety. A quick flip can save severe engine damage. Rubber coating on the switches seals out moisture and dirt, helping the electrical system to work when it matters most.

Battery disconnect switch location is vital as well. Often, I have seen team members turn on the main power switch as a poor mounting location puts it out of the reach of the driver. In the event of a wreck or fire, drivers need to turn off the battery power quickly so mounting location must be within easy reach of the driver.

A red handle makes finding the battery disconnect switch easier for track saftey workers. Large engraved On/Off letters identify the off position clearly so safety workers and crew members can visually see the power is off in the event of trouble. Isolating the battery during the week helps to ensure that your battery maintains a full charge.

All series should mandate a common battery disconnect mounting location that is easily accessible by outside track safety workers. We race for fun and something as simple as the battery disconnect switch location should be “engineered” verses being placed where it is just easy. Utilizing a 2 pole battery disconnect switch is highly advised and really is a requirement if you run an alternator. Turning the red handle to the off position on your battery disconnect should shut down electrical power to the entire car. While these things seem simple, their importance grows when you have been around racing for your entire life. After many years in the industry, safety issues can and do happen to people you know and incidents are not just headlines in a racing paper. Thinking out the battery switch location takes little time. Cultivate an environment that makes safety a priority for every team member regardless of their experience.

A sealed 2-Pole Battery disconnect switch keeps dirt and moisture out of switch. The small terminals are designed to disconnect alternator power and the large terminals isolate your electrical system from the main positive lead on the battery for safety.

As I write on the plane, my laptop battery is fading. I am past deadline and must get my writing done on this flight. Luckily, this plane has a power outlet to keep my laptop working. I know the outlet is down there but, I find myself fumbling around trying to get my cord plugged in and the outlet location is, well it is “awkward” to say the least. It is fantastic that there is a power outlet close by and I am happy I am not limited to 2 hours of laptop battery power. Still, how can an engineer pick the location for my nearest outlet in a spot that would be illegal in 15 states? Somehow, the outlet is between the legs of the woman next to me? Even though I know the outlet is there, getting my cord plugged in is extremely difficult. Plugging in my cord between the legs of a woman next to me couldn’t have possibly been the only way available outlet location on this big plane?

I asked the nice skirt clad lady to plug the cord in for me. It is taking her awhile. It’s ok, the show is much better than the in flight movie on my baby shaken glared filled screen, I have the entire flight in front of me for my red face to return to normal. Since we land in New Jersey, maybe this is my unplanned audition to replace “The Situation”? Really, an engineer with a college degree could only think of placing the outlet where Hugh Hefner keeps his frequent flyer miles? While entertaining, I think we as backyard engineers can use the airplane outlet example to lay out our cockpits for optimal use.

For drivers to win often, they need to feel in control. Their hands are on the steering wheel for the entire night. Locating the steering wheel in perfect position will give your driver the feeling of control. Adjusting the steering wheel is a time consuming effort and every team should find the perfect steering mounting position for their star driver. Steering wheel spacers can easily be installed and close tolerance steering wheel disconnects are mandatory. A solid steering system, free from slop, connects the driver to the track and pure feedback increases speed and reduces fatigue. Steering wheel spacers are built in a variety of thicknesses and even small quarter inch increments can be the difference that creates optimal feel and control. I always recommend large 17” steering wheels, mounted close to the chest to reduce back strain. 15” wheels are quite common. Adding even an inch in diameter reduces strain and helps drivers to stay fresh. Performance is improved if teams spend the time to visualize mounting the steering shaft properly.

Mounting your steering wheel in a comfortable position keeps your driver there at the end. Spacers come in a variety of thichnesses allowing your team to fine tune the steering wheel position. Even if you driver ate too many hamburgers during the week, you can quickly change the spacer for optimal comfort.

An adjustable steering column mount makes it easy for drivers to adjust the wheel while they are right in the seat. Column mounting experimentation allows the driver to find the best angle and wheel position. An angle adjustment may require another try with bolt on spacers. Trial and error coupled with minimal effort and teamwork will provide needed driver comfort.

A bolt on steering column mount is adjustable side to side and up and down. Drivers can make quick adjustments while they are sitting in the seat so that they can dial in the column position perfectly.

A leg support bolted to the steering column gives your driver a comfortable place to rest their leg. On a long race the effort required to hold the weight of a leg for 150 laps increases fatigue. Comfort here provides needed energy that can be used elsewhere helping your driver win more races. The G forces on left hand turns are handled easily with a well positioned padded leg support.

Along with size, drivers need to decide what creates the best feel. If you go to a dirt track 99% of the steering wheels will be uncoated and drilled for weight savings. Dirt drivers insist on lightweight everything. Even the added weight of rubber coating on their steering wheel effects performance. Tradition dictates no rubber coated wheels on dirt.

When dealing with Asphalt teams, it is rare to see a steering wheel without a rubber coating of some sort. The rubber provides added grip and the tacky feel gives drivers the control they need. Vibrations are absorbed and chassis feedback through the steering column is enhanced. The standard on asphalt includes the use of rubber coated wheels and the opposite is true on dirt. I sometimes wonder if dirt and asphalt teams should experiment to see if they can learn from other forms of racing. You never see coated wheels at a dirt track and you never see bare aluminum wheels at an asphalt track. Maybe it is time for the different groups to see what the other side is thinking?

Coated wheels are common on asphalt tracks and a tacky grip helps drivers to maintain control. Dirt cars rarely use rubber grip wheels and most often go with bare aluminum for ultimate weight savings. Maybe the two groups of racers should get together and discuss why they take the opposite approach. I think sharing information between dirt track and asphalt teams would open up an entire new area of learning for both groups.

When your dream destination is a road that circles about until the wind unfurls a checkered flag directing your team to Victory Lane, then taking time to understand the decisions that created the non-stop winning route will keep you on schedule to repeat the journey. Engineering to win is simply a compilation of choices that provide the individual ideas needed to propel groups towards consistency. Small steps guide predetermined construction elements that produce a winning routine. Planning reveals the path to your desired destination. Once your team sees the winning path, engineering to win becomes the programmed norm and the desire to win is transforms competing into a tradition of winning.

Go Forward – Move Ahead

Jeff Butcher
Courtesy of JOES Racing Products
12/1/11

Oil Flow to Go

2011-11-09T08:58:00.000-08:00

Engines are expensive. Helping them last is important for every race team and finding extra horsepower is always a gift that keeps on giving. For horsepower and longevity, the oil system pumps black gold through the veins of your car while facing extremely demanding conditions. Dry sump pumps are the heart of many race engines and understanding a few basics will allow the heart of your car to extend the life of your engine while maximizing power.

A Remote Oil Filter Mount allows teams to locate the oil filter nearly anywhere. A mount that rotates will compensate for bars that run on an angle so you can keep the filter level.

AC Nutter is an engine builder that builds high horsepower engines that have won numerous championships. AC has earned his reputation as a top builder through hard work and self learned creativity. Nutter engines include many ideas developed by AC through his years of hands on experience with top race teams. To support his Nutter engines, AC felt he could help his teams by designing and manufacturing his own dry sump pumps. The combination of being an engine builder and a pump manufacture gives him a unique perspective in understanding how to feed engines with oil properly.

What are your thoughts on a dry sump venting system?

Nutter:

With a dry sump, the vent system must be designed to allow the engine to breath. A proper vent system prevents leaks and keeps precious oil in the car. Too often, tracks are oiled down due to venting system problems. With a three stage pump, it is a good idea to vent the engine valve covers along with the oil tank. You can use breathers on the valve covers or run a line from the valve cover to the tank and use the same vent for both the engine and the dry sump tank. I agree with AC and from my experience vent systems experience less trouble when you run a #12 line from the valve cover back to the tank and let the system breath with a vent back at the dry sump tank.

If you need to vent your engine at the valve cover, a breather kit can easily be welded at a location that allows teams to install the engine without impacting chassis bars.
Nutter:

With a 4 stage dry sump pump, only the tank needs to be vented due to the added vacuum created by the additional stage. Utilizing a small baffled breather tank, with a vent on the top, nearly eliminates venting issues. Be sure to mount the breather tank as high as possible and as far to the left as you can. Connect the dry sump tank to your breather with quality hose. G force will help force oil that collects in the vent tank back down into the dry sump tank. With the breather tank mounted high, there is enough line length to allow gravity to keep the line clear so air can pass through easily. Be sure to avoid any droops in the vent hose to prevent oil from pooling in a low spot. Pooled up oil in a line can prevent the block the vent creating an oil mess that can potentially take you out of a race.

A good Oil Filter Cutter allows you to quickly cut open paper style filters. A quick inspection allows teams to find particles and debris that may indicate a serious engine problem. Paper filters are excellent at filtering out fine particles and are often used in conjucntion with cleanable mesh style filters.

With a dry sump – what do you recommend for line sizes?

Nutter:

The line size question is a big one with many variables and lots of diffenent answers. The most common system would be #12 lines from the pan to the pump. #12 is used to feed oil to the engine with a #16 line to provide a free flow of oil to the tank. Often, I think a #10 line from the pan to the pump is a better way as it provides more overall vacuum and improved performance.

How many stages do you need in a dry sump pump?

Nutter:

My first answer is to let your engine builder decide. Most engines that require a dry sump are in the high end category and your engine builder will understand all the variables that apply to your type of racing. Rules come into play as well and an experienced engine builder can design a dry sump package that meets the needs or your rules, race series and budget. On the surface, this seems like an easy question but there is much to consider and your engine builder will have a philosophy that creates an oiling system that meets the needs of your engine package and series requirements.

A three stage pump supplies ample oil to the engine. A four stage pump creates more vacuum. The added vacuum moves oil away from the rotating crankshaft assembly, producing more horespower.

For a general answer, a three stage dry sump system works as well as a four stage system when it comes to prolonging engine life. 3 stages are plenty adequate to provide a steady supply of fresh oil to the engine. 3 stages obviously saves cost over additional stages as the pump cost is less and the car plumbing is simplified. Your team saves the work and the expense of added lines and AN fittings – those things add up in the cost column.

However, four or more stages will create more horsepower. 3 stages supply oil to your engine just fine – the added stages create vacuum in the oil pan and crank case area. Vacuum causes the oil to lie down in the pan to be efficiently picked up by the dry sump pump scavenging system. With the excess oil pulled down in the pan, oil is not picked up by the rotating crank and rods that spin at high RPM. Reducing the amount of oil that gets wrapped around the rotating assembly, results in horsepower gains. The engine can simply spin more freely.

Oil splashing around the pan and onto the rotating assembly robs horsepower. A fourth dry sump stage creates vacuum and reduces the amount of oil that splashes around inside your engine allowing the rotating assembly to rotate freely. Oil is thick and viscous. If the crank assembly has to beat its way through a pig pool of oil it will have to work harder. The beating action reduces oil life and can cause unwanted foaming. Basically, it is easier to walk down the street than it is to walk neck deep in a swimming pool. By removing oil from the pan, by utilizing vacuum created by the dry sump pump, you will find gains in horsepower. In our testing, we have found as much as 12 additional horsepower with a 4 stage dry sump pump as the rotating assembly can spin without having to fight through a pool of oil in the bottom of the pan.

Creating 8 to 12 inches of vacuum is all that is required to keep the rotating assembly free of excess oil. If your engine runs low tension oil rings you might need 18 inches of vacuum, or more, to keep oil away from the rotating assembly. Your engine builder can assist in making decisions. Something as simple as changing oil ring tension has an effect on the dry sump pump system and the vacuum needs are completely different depending on the ring design you run. Customers will experience less engine trouble if they recognize that a high performance engine is a package and even small changes can be interrelated – one thing affects another and each change needs to be thought completely through.

What do you consider in a dry sump system?

Nutter:

When using dry sump pumps you need to consider the entire oil system. Just a few considerations are dry sump reserve tank size, vent tank type and size, number of stages needed, plumbing line sizes and more. Pan design is a very important element. When it comes to oil pan designs, you want to use a pan that is as wide and deep as possible.

A Dry Sump Breather Tank should be mounted high so oil can easily flow back to the tank. Lines should be routed free of droops so oil can't pool up and plug the venting system. This tank has a drain valve in the bottom so teams can verify that oil is not backing up in the oil system.
Scavenge filtering and engine oil filters must be considered. I prefer oil filters without a bypass. The dry sump pump mounting and drive system varies from car to car and choices must be made that ensure that your dry sump pump is mounted securely with a drive system that will perform 100% of the time. Nearly every dry sump pump on the market is of good quality. I recommend that teams purchase what they can afford and design an overall system that mates up with their rules while placing emphasis on their individual budget. It does little good to install a system that you can’t afford to maintain. In general, the more you spend on a dry sump pump then the more expensive it is going to be to maintain.

What to your recommend for oil filtering?

Nutter:

Paper filters clean oil just fine. Cleanable filters provide the added benefit of allowing you to easily check your engine for debris. Early identification of particles in the filter can save big money on repairs. I like a 60 micron filter with no bypass. If the filter plugs, the oil pressure will drop and your gauge will warn you that there is a problem. The same warning gauge has no way of telling you that dirt is going through the engine so a bypass is a not something I use on my engines.

For the scavenge filter I like a 60 micron filter for the initial start up on a new engine. After a proper warm up, I install a 100 micron scavenge filter before he car goes out on the track.

What about dry sump servicing?

Nutter:

Anytime you freshen or repair the engine you should service the pump. Dry sump pumps are designed so that there is not much that goes wrong. Basically, go through the pump whenever you go through the engine so that you can make sure that the pump was not damaged by a past engine problem. If you have just freshened your engine, then of course you want to protect your investment by ensuring the pump is up to spec.

What about engine oil?

Nutter:

One thing I believe in is that on most engines I like to use thin oils. You should certainly consult with your engine builder but, for my stuff 20 weight oil is most common and 30 weight is the absolute maximum.

Butcher:

By thinking out your dry sump system, you can increase your engine life and find more horsepower. The investment pays off in less rebuilds and improved performance. If your rules allow it then a dry sump pump is highly recommended. Quality oil can be thin and a vent system that supplies clean air to your engine will help your car to flow straight to the front.

Go Forward – Move Ahead
Jeff Butcher

Courtesy of JOES Racing Products
10/1/11

Keeping It Cool

2011-09-12T13:40:00.000-07:00

As cars go faster, air openings feed engines with an ever decreasing amount of air. Watching Bobby Allison slide his Penske Matador through the turns on a half mile or at Daytona was cool – the engine had plenty of air for cooling and the Matador nose could double as a snow plow during a heavy Michigan winter. In those days, the front opening on the car was so big you could use a racecar grill for a BBQ cook top that would hold enough steaks to feed the entire Allison clan.

Adjustable radiator mounting brackets allow for quick experimentation. The roll bar clamp on brackets lets teams adjust the mounting angle quickly. Down force and radiator surface area can be optimized in seconds. Over time, teams can identify the optimal mounting position utilizing hardware that is designed to promote easy adjustment.

Going back in time, stock cars were built to bump, grind and to slide around - aero down force was reserved for Formula 1 and Indy. Dents in the fenders had little effect on speed. Today, an 1/8” variation on a stock car front fender width can take the car from loose to an aero push with the slightest of bumps. Grill of today perform only one hot dog at a time.

A Penske Matador, with an Allison at the wheel, could actually use muscle to power on to victory lane. Cars that rely down force are required to baby their way around the track and the grill opening feeds a finely metered amount of air to the radiator. While old school was more fun, it seems we are stuck with finding more aero advantage and driver muscle is reserved for Sharpie’s and autograph lines.

Since it seems unlikely that stock car grills will be coming out of ’55 Chevy’s anytime soon, teams face the challenge of keeping the engine at optimal operating temperature while maintaining an anorexic grill opening. The optimal grill shape - thin with nothing other than well placed tape directs air precisely. You would think stock cars were getting ready for the Red Carpet and Hollywood Paparazzi verses lining up for the starting grid.

When it comes to the coolant system, proper radiator mounting is an area where cooling can be maximized and speed can be gained. From experience, with plenty of room for debate depending on the car type and track, 7 degrees of forward mounting angle at the top of the radiator increases the radiator surface area while producing additional front down force. Air ducting from the grill opening needs to be tightly sealed and shaped properly to provide maximum cool air while traveling through a minimum space.

Radiator duct panels should be wide and flat (nearly parallel to the ground) at the bottom. Extending the bottom panel of the radiator duct work out at the nose piece is a “semi-legal cheat” that helps seal the nose area of the car with a “belly pan” that is disguised as radiator duct work.

Often, teams build the grill duct work the same width as the radiator. By extending the width of the bottom panel at the front of the car, you can gain some down force by using the bottom sheet metal radiator duct panel, at the nose piece, wider than the radiator. The duct work sides can still seal at the grill opening extending back to the radiator. Proper radiator duct shape enhances air movement for efficient cooling. “Stretching” the bottom panel outside of the grill width gains you a few inches of belly pan and it is likely that it won’t be noticed by the competition and often gets through tech without issue.

At the nose, the top panel of the radiator duct work should start nearly parallel to the ground with a few degrees of upward angle for the first 6” or so to reduce lift. The top panel transition, after the first 6” or so, should smoothly round up to the top of the radiator producing maximum cooling while producing extra down force. Working the ducting shape in your favor can provide for better down force numbers while improving cooling efficiency.

Since reliance on aero for handling is here to stay, then teams must find ways to manage consistent and controllable engine temperatures while striving for the minimum front end air opening. A variety of options are available to keep things cool in the heat of battle. Like all things in racing, finding many small areas of advantage works much better than hoping for a fix that comes from a single magic source.

IR pyrometers can help teams to identify hot spots providing an opportunity to direct air through duct work to critical areas in the cooling system. Isolating potential hot spots with an IR pyrometer can display areas where more air flow or improved radiator duct shapes will help to drop water temperatures.

An Infrared Pyrometer can be utilized to instantly measure cooling system adjustments. As teams experiment with their coolant system efforts, the IR pyrometer can be used to spot check multiple system locations with precision. Improvements can be recorded and experiments that have a detrimental effect can be quickly rectified by taking multiple measurements with an IR pyrometer.

When experimenting with radiator ducting shapes an IR pyrometer can help you determine if you are making gains. Assuming you are at the same track, with the same outside ambient temperature, you can take an IR reading on piece of sheet metal that is temporarily mounted behind the radiator and in front of the engine. The is plenty of room for error with this method but, if you can repeat the number of laps, time it takes to get to the car, outside air temps and as many variables as possible then you can find improvements over time by taking an IR reading on your test sheet metal and compare temperature changes based on the changes you make.

Examples of cut and try items for improved cooling are radiator mounting angle, radiator duct shapes, grill tape and more. Since short track racers have limited engineering and testing time of Cup teams, it may take weeks to learn which experiments are producing positive results. Still, gains can be found if you are willing to cut and try and spend more time than your competition.

Freeze plug adaptors allow racers to tap the water system, changing flow as needed. With the right hardware water flow can be managed to meet any requirement.

Quality water temperature gauges will provide you great information relating to the average temperature of your coolant. If the IR pyrometer helps you to identify a hot spot in the engine compartment then directing air precisely can help to lower the overall under hood temperature created by outside forces. Saving money on a water temp gauge may seem like a good idea but to produce long lasting horsepower your team must work with your engine builder to identify operating temperatures that produce maximum horsepower. Accuracy is needed to monitor temps to create the ultimate horsepower available.

Locating your water temp gauge probe in the ideal position can help your team to find the “ideal” measuring location. Temperature Tee’s can be installed in line in selected water hoses helping you to measure how your innovative ideas relating to water temperature are performing. For testing purposes, more than one water temp gauge can be installed and your team can use multiple Temp Tee fittings in line on various hoses. Multiple water temp gauges can be used for testing so your team can get take measurements of the water system at critical locations. By checking your water temps in strategic locations, your team can visually see how water treatment ideas are working out.

Temperature Tee's come in a variety of line sizes and allow water temp gauge probes to be located in nearly any location in the cooling system. Successful teams experiment by connecting multiple Temperature Tee's in several locations. Using multiple water temp gauges at key system locations can help you to sort out coolant system issues.

Some engine builders route engine water to manage temperatures at precise locations. Freeze plug adaptors provide easy access to tap into the water system and hoses can be easily installed to route water as needed.

Coolant additives can help the longevity of your cooling system components. Anti corrosives and lubricating properties can be a big benefit and even save money over the long haul. Water cooling claims made by additive manufactures should be considered by each customer and their specific needs – a well designed system is needed and simply pouring in an additive will do little to fix a system that is designed poorly.

Ported Water Outlet fittings, at the intake manifold, are another area where the coolant system can be easily tapped to improve water flow. Adding a Thermo Spacer provides a clean mounting location for water temp senders right at the engine intake – temps taken as water enters your engine provide a great way to verify if your water cooling efforts are headed in the right direction. The additional ports, in Ported Water Outlet Fittings, allow racers to direct water flow to meet nearly any requirement.

Ported Water Outlet fittings can be located right at the intake manifold and are a reliable place to monitor cooling system improvements. Extra ports allow for a quick tap of the water system to directing needed coolant in a simple fashion. An O-ring seal ensures that your system stays water tight.

On cool nights, more grill tape may be needed to get your engine up to operating temp. Heat is horsepower and I can think of many early spring nights where the grill opening was nearly sealed off completely. The added front down force made the car faster as long the corresponding amount of rear down force was added. Down force nearly always wins out over aero drag on short tracks.

A water expansion tank with a Billet Cap Flange has the muscle to perform. Utilizing high pressure lines and quality water coolant components allows teams to run maximum cap pressures. A Billet cap connections ensures a perfect seal as compared to stamped aluminum cap flanges that can fail under pressure.

Optimizing horsepower, by keeping the water temperature in heat range that creates the most horsepower, is managed on a race by race basis. Tape, jetting, fans and the like are tailored based on the conditions that vary each week – sometimes each hour.

A Thermo Spacer, used at the intake manifold, provides easy access to the water system. Creativity can be maximized while maintaining a clean and professional installation. O-Rings keep the water in your engine so your team can focus on making more power.

Competition gets tougher every week and teams that strive to find the smallest gains win more often. I deal with Cup teams that have custom parts made that save only 1 gram of weight. As short track racers, we often think of saving pounds at a time. Cup teams use the finest resolution possible and think in terms of saving a single gram. Over time, the single grams saved pile up and the result is a car that is as light as possible. The same philosophy applies to the cooling system. The teams that strive to explore cooling system improvements will beat the heat and their teams will run consistently hot.

Go Forward – Move Ahead

Jeff Butcher
Courtesy of JOES Racing Products
8/1/11

Proper Tire Prep & Purge

2011-08-24T12:25:00.000-07:00

If you are into skinning cats, you will find that there are more ways to get racecars around corners than there are cats to skin. On the other hand, skins on racecars are what connect your secret set up to the ground. More adhesion at the contact patch creates long lasting speed. Balancing the grip at all 4 corners produces a fast car and any talk of skins can be limited to tires – you can leave the cat lady alone. Maintaining desired tire size is critical when it comes to being catty enough to win.

Managing tires can be a daunting task. Keeping good notes and having the proper tools for measuring and purging saves valuable time and is often the difference that gets your team the big win.

Bias Ply tires (radials are a different animal) require constant care to minimize variables. Maintaining the desired size and air pressure is an art. With a little care and a repeatable routine, tire sizes can be managed preventing erratic growth changes. Prevention and a dedicated tire specialist is often the team component that keeps your car in the front. Maintaining a consistent approach to tire preparation is what allows you to land on all fours regardless of track conditions.

The goal is to keep the tires the tires sized properly avoiding unpredictable growth. Variables can be controlled or at least reduced. Starting with tires that are manufactured to the desired size is a best practice. Attempting to change a tire size by artificially stretching it with added air pressure is a sure way to produce false sizing numbers that change at the first heat cycle. A good racecar goes to junk if stagger changes in an unpredictable fashion.

Using a tire roller helps to measure stagger (roll out) quickly making quick work out of your tire stack adjustments.

For bias ply tires my general rule of thumb is to use a maximum of 2 pounds of pressure to increase or decrease the size of the right size tires from my optimal pressure. Any pressure beyond 2 pounds, above or below, the ideal right side tire pressure changes the spring rate, camber temps, and tire foot print potentially reducing speed. For left side pressures, I might allow a 3 pound variance but since we tend to run such low pressures on the left side use caution to avoid crossing over the minimum pressure line. Buy the tires at the right size. Spend the time to remount tires that are the correct size.

A 1/4" Stagger tape, used with a tire roller, gives you price readings. Be sure that your tape remains exactly straight and true on the tire.

There is debate on how much bias ply pressure variance you can utilize to get to your optimal stagger. For this article we are focusing on bias ply – it is well known the radial tires are extremely sensitive to pressure changes and even quarter pound pressure adjustments can be dramatic with radials.

Dave Juarez, the tire specialist at Gene Price Motorsports for the #26 Greg Pursley driven K&N Pro Series West team says, “with bias ply I can get away with 3 to 5 pounds of added pressure without adverse affect. For qualifying, 5 added pounds frees up the car and helps to build heat quickly”.

Growing tires is a bit of a myth. Sure, you can change the size with more pressure but making a tire bigger by stretching it only gains a small amount and that growth is often inconsistent. Dave Juarez says, “filling a tire to 50 PSI and letting it sit in the hot sun can make it stretch. Generally, a heat cycle is needed to keep the tire at the desired size”.

A common mistake I have seen with bias ply tires is that teams over fill tires to “stretch” them in an effort to grow the tires to get more stagger. These teams overfill the tires and then quickly drain the air down to race or practice pressure and take a measurement. This method always ends up with false size readings. As soon as the tire heats up, the artificial “stretched” reading disappears and the tire shrinks back to near its original size. You might grow the tire a fractional amount but if you were counting on the extra stagger to get through the center you can be assured that the tire size will change at race temperature.

Championship driver and JOES Racing Products owner Joe Constance says, “2 pounds of variance is ok to get stagger, 2 more PSI in the rights and 2 less PSI in the works fine but any more pressure change than that and you are fighting evil with evil.

I have seen all kinds of tricks to change tire sizes. Over filling tires and bouncing them like a basketball to gain size. I have seen teams run too much air pressure in practice to help grow tires with a heat cycle – go too far and you risk cooking cooks the tire center. I have seen teams try to shrink left side draining them of air after a heat cycle and then dousing them with cold water. This method can harden the tire and rarely has much sizing benefit. It is tough to change once a tire is manufactured. Adding pressure or dropping pressure will get you a size change but really the size is determined at the time of manufacture.

Juarez says, “I have bounced tires also but it is a desperate last resort. You might be stretching the center of the tire but I wonder what is happening to the contact patch? It is hard to stretch a tire at the side walls. I still think you get what you get and after one or two heat cycles just count on tires being about that you originally measured. I have had tires stretch or even shrink during a race but it is out of your control. Just be very consistent with the way you prep your tires and you get a pretty good feel for what they are going to do”.

Dave Juarez states, “if you get a heat cycle on a tire and quickly drain the hot air and replace it with cold nitrogen the second the car comes off the track you can make the tire a little smaller or at least keep it from growing more”. Dave continues, “Adding nitrogen to a hot tire can help it to grow but not all that much”.

Joe Constance says, “I never had any luck stretching tires on my Saturday night racing. I like to put 30 psi in the lefts and 50 in the rights and leave them for 30 minutes to let them get a set when they are new. After you put a heat cycle in them you get what you get. You can make them bigger or smaller with air pressure but you need the right size tire with the right pressure to be fast”.

Using nitrogen instead of compressed air helps with consistency. Nitrogen is nearly moisture free and air from a compressor contains moisture. You get moisture in the actual air but you can also get a lot of vapor from the compressor tank and lines. Moisture inside the tires creates added heat expansion and if any tire contains more moisture than the others in the set then stagger changes unpredictably.

Purging air out of your tires and replacing it with nitrogen will remove moisture resulting in consistent stagger throughout the race. This purge tool has a slide collar to "dump" air quickly through fast flow ports that can be used when your tire specialist is attending to the tire. The collar slides to the closed position and a bleed valve prevents air and unwanted atmospheric moisture filled air from re-entering the tire during the purging process allowing your specialist to work on many tires at once. Top teams use multiple purge tools. The purge tool clips on the Schrader valve and automatically adjusts your tire to nearly any pressure allowing your crew to multitask with confidence.

Nitrogen works well. Top teams have used Argon in their tires to further reduce moisture content. Argon and medical grade nitrogen produce such a small moisture reduction benefit that it is not worth the added cost. Dave Juarez states, “I have tried Argon and some other types of Nitrogen. Medical Grade Nitrogen was believed to be the preferred type but I did some research and found out that the only reason it is classified as “Medical” is the way in which the tanks are cleaned and filled. The chemical make-up is the same so there is no advantage within the tire”. Basically, Dave thinks standard nitrogen is a good economical choice.

Clipping on a purge tool to several tires allows tire specialists to replace moisture filled air with clean and moisture free nitrogen in record time. This purge tool clips on and can be set to very low PSI, preventing atmospheric pressure from re-entering the tire. The clip-on feature allows the tire specialist to set race pressures by adjusting the bleed valve, from very low, to maximum race pressures. Top teams have several purge tools clipped onto multiple sets of tires. On hot days, the clip on feature, allows teams to automatically bleed off pressure created by heat build up from the sun.

Joe Constance takes a practical approach and takes care to keep water out of the tire during the mounting process, Joe explains, “Keeping water out of the tire during the mounting process is a big deal. If you are not careful you can get a bunch of mounting soap and water in one tire and half as much in another. I like to use WD 40 for mounting tires. WD stands for water displacement. The WD 40 lube is slippery enough to mount the tire and you can keep the tire sized right by avoiding using water all together”.

I have seen all kinds of devices that claim to eliminate moisture in tires. The goal is to maintain consistent growth. The practical goal is to have the tires grow in concert with each other so that set size is predictable. I once had a guy that wanted me to build and market a $60,000.00 dollar vacuum chamber to pull the moisture from each tire. The reality is that there is moisture in the tire rubber. The moisture inside the rubber is part of the manufacturing process and is a needed element for tire performance. Taking care of your tires is good but a $60,000.00 vacuum chamber gains you about zero in performance yet costs you a ton. I wish I was joking but there are folks that think a $60,000.00 dollar machine would be a good deal for short track racers. I am embarrassed to even admit I know about such a machine.

Using a top quality pressure gauge fine tunes your stagger with optimal pressure. This gauge comes complete with an angled chrome chuck and a ball chuck ensuring it works in every application. You always have the right gauge and can avoid worrying about being committed to one style of chuck. Racers can change out the chuck in thirty seconds as, for this gauge, the chuck threads on so teams can change as needed.

Juarez says, “I have used air dryers, desiccant moisture removers, clean nitrogen and so on but the most benefit is gained by having a consistent plan”. Depending on conditions, I purge the tires with nitrogen a minimum of 2 times but generally would prefer to use a humidity gauge and purge the tires as dry as possible. Usually it is 4-5 purges that are needed to purge down to a “zero” state – well near zero”. Dave continues, “If I am mounting the tire, I use the least amount of tire “soap” or mounting medium. When I seat the bead I use compressed air that goes through a dryer first”. Dave goes on, “you can create some stagger starting your right side air pressures slightly higher than “recommended” during your initial practice run on stickers but only if scuffs are allowed by your series on pit stops. When you run slightly higher right side pressures, the heat cycle in the tire will “hold” a bit more stagger.

Personally (Jeff Butcher), my goal in managing tires is to work with the tires and not against them. For short track cars and sticker tires I always put 20 PSI in the lefts and 30 PSI in the rights – I made sure the guys at the tire truck didn’t over inflate them from my numbers as I wanted the tires to be in their natural state every week without crazy air pressures that produced variables. In my experience, consistency allowed for predictability. Artificially growing tires was a sure way to have the stagger change during race conditions. I did make sure water was kept out of the tires and I used standard nitrogen, medical grade simply was a cost item that didn’t equal the value. I purged the tires 2 times as that seemed to be the point where the most benefit was gained. Purging more than 2 times gained a little but it takes time and our hauler had a limit on how many heavy nitrogen bottles it could carry. We had a nitrogen sponsor but 2 times seemed to remove most of the moisture. Consistently purging 2 times each week was a “routine”.

I think the mistake that is made by many teams is that cold measurements, taken after stretching “tricks”, create dramatic size changes that disappear during/after a heat cycle. The tires are what they are based on how they were manufactured and to think you can stretch the sidewall seems like a “mental stretch” to me. Really, you would have to break down the side wall cords to grow a tire so in my view, high using high air pressures with the goal of making a tire bigger simply ballooned out the center of the tire for a short while and any stretch is a mirage.

Joe Constance says, “I have only used nitrogen but if you are going to slop a bunch of tire mounting goo with moisture in it on the bead before you mount it you might as well save some money and just use air from your compressor. It is very important to keep the inside of your tires as dry as possible”. Constance continues, “I am around a lot of teams that are on a budget and they may only have one nitrogen bottle - it would be nice to purge tires two or three times but they don’t usually have the time or money. Since many teams only carry one nitrogen bottle to the track, one purge becomes the max. As long as they are consistent they can usually calculate how much the pressure will grow”.

Matching sets, especially when you have multiple new sets, is part of the art performed a tire specialist. Dave Juarez states, “In a perfect world, the left sides would all be the same and the “average” would come from the right side tires”. Dave continues, “I try to match sets so you could switch left sides to add or deduct stagger on pit stops. I tend to lean toward using my Right Side tires to add or subtract stagger since the Right Side Tires take most of the load during a race. Most often, the 2-tire stop is right sides so having the option to switch tires around coupled with adding/removing air pressure is critical to handling and performance after a stop”.

Dave thinks, “Most of the pressures and tire sizing depends on your application or set-up. Most drivers can’t tell the difference in 1/8” of static stagger. During a run when the air pressure builds, the associated stagger change and air increase will have the greatest effect on handling. Pay closest attention to your “set” choices based on the set-up and handling of the car. If the Crew Chief and Driver are on the same page, it is far easier to “follow” and “manage” your available set options which is a big help in selecting sets for the race and qualifying. Nowadays, it is more important to keep your “brand” or serial numbers as close together as possible so your tire inventory comes out of the same batch creating added consistency.

Joe Constance says, “I love Saturday night racing and pit stop races are rare for the cars I have driven. The few pit stop races I have done were under budgeted with a limited crew and we made the best out of our hard working Bad News Bears volunteers. I had some knowledgeable long term faithful help but we often didn’t have enough manpower. Often, we had the track mascot or trophy girl changing the right rear tire on pit stops. I do know that you can feel a ¼” of stagger difference and even that small amount has a major effect on handling so know your tires is critical.

Joe continues, “Communication between the driver and crew is important and using different tire sizes to dial in the car can get you to the front. A well chosen stagger change can be huge. Making sure you know what tire sizes are on the car at all times helps you select the best set of rights or lefts and keeps the monkey in its mascot suit preventing your team from doing inappropriate things to a football.” (Joe said that quote a bit differently so I edited his words for the article – I am all sure you all can figure out what it looks like when teams do inappropriate things to a football after a Keystone Cops pit stop).

Constance believes, “I always try to get all the same size lefts, I vary the rights about a ¼” going off of the sizes marked on the tires when new because they are never exactly what they say they are and this gives me some adjustment during the race. I always try to keep the rear stagger the same and compensate for the wrong front stagger with other chassis adjustments. The goal is to have the best set for the end of the race. Only the last lap counts!

Dave Juarez, “I like to use a tire roller and I trust a tape measure more for precision. I will measure along the tire shoulder when the tire is on the ground when needed and easily get accurate and repeatable results. I also need a stagger tool as in our series we are not allowed to jack up the car post qualifying”.

A billet CNC machined tire caliper gets you an accurate tire size readings quickly without the need to jack up the car. Many race series impound the car after qualifying making a precision tire caliper invaluable.Constance agrees, “I like a tape measure because it is a little more accurate. Adding a tire roller just makes the measuring process so much easier. Being consistent and using a quality tire pressure gauge improves speed. Take tons of notes on your tire sets, and keep the inside of every tire as dry as possible. Experience is invaluable and the more knowledge you can gain the faster your team will run. Tires are everything so have a tire specialist on your team that is detailed and thorough”.

A quality tire specialist helps any team win. Tire experts are the hardest working people in the pits and need to react precisely to split-second decisions made by demanding crew chiefs. Top Cup Crew Chief, Shane Wilson, relies on JOES Racing employee Robert Osaki, flying him around the country for special events. Robert is well known for being the nicest person on the planet and is regarded as one of the best tire specialists in the business. Here, he is shown helping Gene Price Motorsports get their rubber to the road at Infineon Raceway in California.

Tires are a big investment for any team and a good tire guy is invaluable. Just think about the last pit stop on a big TV race and how the tire guy can mess up the fastest car on the track by handing the tire changer the wrong size tire or one with incorrect air pressure? Managing and massaging tires is an art. JOES Racing Products employee, Robert Osaki, is known as one of the best tire guys in the business. Top teams such as Gene Price Motorsports and Kevin Harvick Industries fly Rob around the country, at great expense, because they can trust that he knows his tire stack inside and out. Rob’s knowledge, care and experience make him an asset to any team. To win races, your team needs a tire specialist that treats each tire like family. Find a cat like Robert Osaki and your car will always go on all fours.

Go Forward – Move Ahead
Jeff Butcher
Courtesy of JOES Racing Products
7/1/11

Power Steering

2011-07-20T12:36:00.000-07:00

Before racing power steering, caster was utilized to help cars turn left. Manual steering provided great feel but required Popeye forearms to get through the corners. Many drivers of today might fall out of the seat if it were not for the utilization of advanced power steering systems. It is clear that many drivers have extended their careers due to the power assist.

Serpentine belt drive power steering pumps are more durable. Today's advanced power steering systems are a giant leap forward compared to designs of the past. These advanced systems increase horsepower by utilizing smaller light weight pulleys and lighter belts. Serpentine belts eliminate slippage that can occur in V-Belt systems. New advanced power steering packages maximize flow and are more efficient resulting in marked improvements on the horsepower dyno sheet.

Through technological advances, driver feel is optimized by advanced power steering systems and caster is now used as a chassis tuning tool. Steering effort relies on the precision built into the power steering system independent of chassis and caster settings.

Power steering pumps, and components, are precision instruments that are built with the latest manufacturing technology. Close tolerances are a requirement for power steering systems to perform. To sort through the intricate details, and variety of power steering application options, we sought out racing power steering experts CJ Jones of Jones Racing Products and Michael Deppa of KRC Power Steering. Both companies utilize advanced power steering systems. The differing philosophies of these manufacturers offer racers a variety of successful power steering package choices.

What are the recent advancements made relating to racing power steering systems?

Michael Deppa:
Coil bind set ups, wide soft compound tires, high amounts of caster and fast steering boxes place more demand on the power steering system. Faster racks, small ratio steering boxes or quicker steering boxes often require more volume feeding the servo. Aggressive front end geometry and high banked tracks can place high amounts of load on the wheels. Faster rack-and-pinions require more volume to fill the slave cylinder due to the quicker cylinder stroke. Manufacturing advancements allow for managed pressure relief settings, in the pump, even at the high pressure.

Pavement late models, on semi-banked tracks, often create around 600 PSI of pressure in the middle of the corner, while Modifieds at Bristol create 1500 PSI – Dirt cars can see the same 1500 PSI. Hardware has changed to meet the new pressure challenges and changeable flow valves allow pump volume to be adjusted throughout a large range for precision tuning in varying applications.

CJ Jones:
Through research and testing, our team discovered that power steering pump performance relied on building systems with a solid foundation which allows the pump’s internals to provide excellent fluid control, pressure and flow curves along a wide RPM range. . Machined CNC Aluminum construction, manufactured with exacting tolerances, provides the rigid platform required for the best performance. A solid foundation allows the internal pump components, and flow controls, to provide optimal fluid management and pressure stability. Fluid flow curves, throughout the RPM range, can be specifically tailored due to the rigidity engineered into the CNC machined housing.

Our extensive testing illustrated that matching pumps with integrated fluid reservoirs created optional solutions for the racing market. An integrated fluid reservoir simplifies installation and is more cost effective. Removing the remote tank eliminates four fittings and two hoses. Overall system performance is enhanced, and restriction is reduced, due to the elimination of unnecessary hoses and fittings. Integration ensures fluid feed, at the source, providing advantages as compared to remote reservoir designs. The performance of the entire system is enhanced; there is never a possibility of the pump struggling to get fluid from the remote tank source.

An integrated reservoir tank eliminates hoses and fittings increasing flow characteristics. With the tank mounted right at the pump fluid is ready available to feed the pump reducing cavitation.

Explain your thoughts on power steering fluid.

CJ Jones:
We tested all the available fluids and our group felt improvements could be made by producing a synthetic fluid designed for the racing market. Synthetic handles extreme temperatures nicely resulting in steering consistency throughout the fluid temperature range. A confident steering feel, from race start to finish, is obtained due to the performance of our proprietary synthetic fluid. Foam free and crystal clear synthetic fluid eliminates cavitation during full operating temperature even on long green flag runs.

Clear power steering fluid helps the team to keep a watchful eye on the stability of the system with just a quick glance at the fluid itself. Racers are able to spot any type of contamination in the fluid, helping to catch any problems with the rack, steering box or hoses. Catching one of these problems will protect the rest of the system.

Weekly fluid inspection should be standard practice and a complete flush and fluid change is recommended 2 to 3 times a year. If you run more than once a week, or often run in long events, then increasing the fluid change schedule is recommended. Racers should adapt their schedule based on their usage but 1500 to 2000 laps is a reasonable guide for synthetic fluid replacement based on a standard weekly Saturday night type schedule. Contaminated, debris filled or burnt fluid should be replaced immediately.

Whether you choose a full synthetic fluid or a petroleum based fluid, utilizing clear fluid provides the opportunity for system checks with a quick glance. Clear fluid that is discolored gives teams a heads up in identifying potential problems in the power steering system. Hose issues or other problems are quickly resolved when clear fluid suddenly becomes discolored. Purchasing small bottles for top offs and large bottles for full system fills ensures efficient use of your fluid.

Michael Deppa:
We like petroleum based fluid as it is incompressible and safe for internal system components. Low viscosity petroleum based fluids flow through the passages of the pump with a constant density through pressure change. Petroleum based fluids cool nicely and are readily available. Fluid issues, such as boiling, give racers an opportunity to inspect the entire system. Corrections can be made right at the problem source that is creating the fluid boiling point.

Pavement cars sealed off tighter for aerodynamic purposes may benefit from a cooler. Lower fluid temperatures provide fluid integrity but generally a cooler is not mandatory. If a cooler is used, the best place to mount a cooler is in front of the radiator so the ducting forces the clean cool air through the cooler.

We recommend the fluid be changed roughly two to three times a year in most racing applications, but it should be changed immediately, along with a thorough flush, if the fluid is discolored or smells burnt. It also should be changed more often if you race more than once a week on a regular basis. Before every race we recommend checking the power steering fluid level. Using clear fluid as a diagnostic tool makes it simple to spot problems and discoloration.

Other weekly maintenance includes checking your belts and pulleys for wear, checking belt tension, clearing pulleys of debris, and inspecting your hoses and fittings for any leaks.

How do you determine pulley sizes for power steering systems?

Michael Deppa:
For racing applications you should ensure you do not over spin pumps at RPM levels above the pump rating. Special caution should be utilized with an OEM pump to avoid excessive RPM. Manufacturing pumps, specifically for racing, allows for increased RPM’s in the 9000 range.

To determine the correct power steering pump pulley size, you should consider that most constant flow vane-style power steering pumps achieve maximum flow rate at 1500 RPM at the pump. A well designed pump will flow at a constant rate from 1500 RPM of pump speed on up. Over spinning the pump will not increase the flow rate of the pump. We recommend turning our pumps, on most engine set-ups, at around 4,000 to 5,000 RPM of pump speed. In some instances, such as dry-sump mounted pumps, the pump may not be spinning fast enough at low engine RPMs to get maximum flow out of the pump. This may cause the steering to feel tight in the pits. The key is to make sure the best feel is found at race speeds. Racers can go online for the pulley RPM formula or consult or techs for specific information to ensure all variables are taken into account.

CJ Jones:
We recommend that racers identify power steering, pulleys and mounting hardware based on the engine RPM range and the accessories on their car. Power steering pulley size is used to fine tune the pump speed for optimal pressure and flow curves. Ensuring a cool running pump, that is mounted properly, is obtained by utilizing the vast array of configurations available. A call to our techs can help teams to achieve the best system for their application. Equal effort can be placed in improving existing systems for maximum performance even if a team is enhancing their existing system verses starting from scratch. Regardless of the scenario, expert tech support can make dramatic improvements in power steering performance.

Why are serpentine belt systems better?

Michael Deppa:
Serpentine belts are capable of withstanding higher RPM’s without the belt stretch that can be seen with V-Belt systems. V-belt stretch causes slippage and rapid pulley wear. The Serpentine belt structure requires less material, thus the belt itself is lighter. Serpentine belts provide greater grip to the pulley allowing smaller pulleys to be used. Pulleys can be made in smaller diameters reducing rotating weight adding horsepower and acceleration. With appropriate tension, Serpentine belts last longer and coupled with smaller pulleys the long term cost savings are significant.

CJ Jones:
We searched for alternatives to V-belts over 30 years ago and found serpentine systems improved the drive of accessories at optimal RPM. Serpentine pulleys offer multiple light weight ratios that are more reliable at the high RPM found in racing. The variety of pulley options reduces belt induced horsepower loss. The serpentine concept increases reliability and is a superior alternative to V-Belt designs. Serpentine reliability and longevity are a dramatic improvement over V-Belt systems.

How do you determine the correct pump for a given application?

Michael Deppa:
A major consideration is identifying how the pump is to be mounted. Will the belt drive be on the front of the engine or off the bell-housing? Will the power steering pump drive off the dry sump pump or cam shaft? Once the pump is mounted, the last step is to fine tune the pumps flow rate to the application. Standard flow rates work in a majority of applications but differences in rack-and-pinions, steering boxes or steering gears may require simple flow valve changes to optimize the flow rate to the steering system. 1600psi of pressure relief is the highest safe rating we recommend. We can adjust the relief valve from 1000-1600psi. Other considerations relate to the tank – will it be pump mounted or remotely mounted?

Power Steering Pump manufacturers have developed a variety of mounting options to suit nearly any application. Consulting your power steering company of choice will provide you with many problem solving mounting options.

Explain the advantages of a pump designed for racing as compared to past or stock designs?

Michael Deppa:
GM Saginaw pumps are built for mass production with low cost at the major factor.

Designing a racing pump from the ground up allowed for input from industry expert Tony Woodward. The evolution of pumps specifically designed for racing allows for the use of superior materials and very tight tolerances. Diameters can be held to tolerances of 1 micron. Honing and hard coat processes create longer lasting better performing pumps that go beyond the technical abilities of a stock Saginaw style pump. Improved manufacturing processes provide greater power assist when you need it. Efficiency improvements result in temperature drops of 30 degrees or more illustrating the advances of modern technology.

A power steering pump designed specifically for racing applications reduces fluid temperatures and increases performance resulting in a smooth steering package.

What other power steering system knowledge would you like to pass on to readers?

Michael Deppa:
Most steering issues we come across on a daily basis are due to plumbing issues. The feed line for remote systems should be no longer than three feet and should be a hose designed specifically for power steering with the correct vacuum rating. Push-lock and braided-stainless hose will not work for a power steering system. Once hot, if oil is pumped through these non rated lines, they can soften and will more easily be sucked shut, starving the pump of fluid.

Remote tanks should be mounted above the pump and care should be taken to ensure the line is insulated from header heat. If the line is routed below the pump, and then enters the pump from above, it can create air pockets in the line creating steering with hard spots and inconsistency.

We check the fluid level with the engine off. Care should be used to prime and bleed the air from the system. Primed and bled properly - the fluid level should not change once the engine is turned on, unless there is a leak in the system. The fluid level should be well above the return line where it enters the side of the tank. If the fluid level is not above the return port, excessive fluid aeration will lead to cavitation.

CJ Jones:
Dyno testing each power steering pump, to verify and document flow and pressure characteristics, improves on track performance allowing for specific tuning for individual drivers. Dyno testing is something we feel very strongly about and we believe every pump should be run on a specialized pump dyno. Continual improvement processes are enhanced through the rigorous daily dyno testing.

Serialization allows baseline numbers to be matched so that Saturday night short track racers, or Super Speedway Cup stars, can maintain the steering feel that is best for their situation utilizing years of technical support experience. Storing documentation allows drivers to repeat the feel desired from the steering system for future needs.

Serializing pumps allows for storage of information that can be pulled up for baseline comparison at anytime.

Jeff Butcher:
Utilizing the correct steering wheel size will help your driver to be fresh at the end. Larger diameters reduce back pain and find the correct "feel" is very driver specific. One driver likes the slightly slower and smoother performance of a large wheel and other drivers like the quick reactions of a small wheel. Small wheels can make it more difficult for drivers to be smooth. Working to find the optimal size for each driver is another tool that can make your stopwatch produce smaller numbers.

Using a top quality steering wheel gives the driver maximum feel and feedback. Quality steering wheels are round where as knock off wheels can be oblong creating an erratic feel. Mounting your steering wheel as close to your chest as possible reduces back strain. The best steering pad available should be a must have item for any team.

Quality power steering systems provide excellent feel and keep drivers up on the wheel for the entire race – there is no need to “ride” to conserve driver energy. Running hard every lap is possible due to the design of a good steering system. To maximize feel, your steering shaft should be mounted solidly with the steering wheel located in a comfortable position.

A rigid steering column mounting system gives your driver reliable and consistent steering feedback. Steering columns that flex or have bent steering shafts create unpredictable steering motions. Using the proper mounting hardware is an easy way to ensure your advanced power steering components are fully utilized.

Mounting the wheel as close to the chest as is reasonable allows more leverage to be applied to the steering system and back strain is reduced. Proper positioning gives the driver more power in the turns they can stay in the seat for the entire race. A racing steering wheel should be paired with a precision machined steering wheel quick disconnect. Close tolerance splines connect the driver to the wheels for ultimate control while providing the safety of a quick release system..

Steering wheel disconnects are a must have safety item. Tight splines transfer feel from the tires directly to your driver for enhanced feel. There are many quick disconnects to chose from and this is an area where the old saying "you get what you pay for" applies.

Each track, car type and driver style presents many variables. Today’s power steering system manufacturers have the resources to offer the correct hardware to maximize the potential of nearly any car. Smooth and dependable steering feel, with proper power assist, promotes better feedback to help drivers dial in set ups. Drivers can utilize the power assist to go the distance better than ever before and taking the time to work with your power steering supplier will help your team to easily turn into victory lane.

Go Forward – Move Ahead
Jeff Butcher
Courtesy of JOES Racing Products
6/1/11

Organizationally Challenged

2011-06-20T09:25:00.000-07:00

Fast and Furious at the movie theater is much more fun than acting out the Dukes of Hazard at the track. Enjoying a good movie with popcorn and a soda is fun – disorganization at the track leads to insanity and the increased pressure paints a landscape colored with rash decisions. Advanced technology and the variety of adjustment options, increase the difficulty of recording set up information and track side changes. Speed will be created through pre-planning and organization – Chaos not required.

Good decisions can be made when the air in the pit area is calm and an orchestra of advanced planning moves your crew in perfect harmony. A well guided crew, given the proper organizational tools, will lead you to the winners circle by following a pre-rehearsed program where each team member performs based on a plan that is implemented with precision.

Staying organized is accomplished through prior planning. Slowing down to go faster is the recommended path and investing the time to build documentation as you go will allow you to quickly pull data for future use. All chassis adjustments have value whether they make the car faster or not. The key is to document information in a displayable fashion with reliable people taking detailed notes every step of the way.

A coordinated organizational plan, born in the shop, sets in motion a productive route that gets your race week started on the right path. Detailing the shop set up gives you a baseline to chart changes made during the hectic pace that is inevitable at the track. Being prepared, in advance, gets you through Tech Inspection and out running laps allowing your team to take full advantage of every practice session.

In the shop, a Chassis Prep Checklist ensures that all projects are complete and all bolts are tight. Maintenance items can be checked off one by one so the entire team can visually see what is complete and the group can focus on the remaining items to be completely ready the second you get to the racetrack.

Ray Evernham lived by the mantra that "Luck is when Preparation meets Opportunity". After winning the Brickyard, Ray sent me a brick with the important quote engraved into the brick. The gift was a thank you for being a tiny cog in their championship effort. Ray took the time to thank all that helped their team win and the quotation, etched permanently in red brick, is a daily reminder for me to be prepared on and off the track.

You can Download the JOES Chassis Check List Sheet at the JOES Knowledge Center http://www.joesracing.com/kb/index.php

For all of my race teams I invoked a shop rule that stated, “If you bolt it on you tighten it up in race ready condition – every time”. Many times crew members simply hang a part on the car and leave it loose because they plan to take it back off or do other work – even then, I require all parts to be wrench tight. It is too easy to forget and too often parts fall off of cars because someone just hung a part in place instead of taking 5 seconds to use a wrench. It takes little time to tighten up race parts – it takes a ton of time to repair damage after parts fall off. Losing a race due to poor shop practices is easily avoidable.

I know the cars I worked on finished every lap because they were always ready to go. I also know that when I was a hired gun, helping other teams, it seemed there was something loose on the car all too often. If you hang it – tighten it. Make tightening parts a hard and fast rule on your team and you will “save” time and save money. A Chassis Prep Sheet will assist in making sure all items are complete and race ready. It pays to place a reliable person “in charge” of the Chassis Prep Sheet.

Keeping detailed notes at the shop and at the track will help your team to be ready right out of the box. Detailing all changes, even changes that don't work out, will help your team to build their knowledge base producing more valuable use of practice time.

You can Download the JOES Chassis Set Up Sheet at the JOES Knowledge Center http://www.joesracing.com/kb/index.php

After your car is race ready then bolting in your winning set up is the next priority. A Chassis Set Up Sheet will give you a central location to make notations in the shop that allow you to repeat winning set ups in the future. Done correctly, documenting your set up fully in the shop displays the information for quick review. An organized Chassis Set Up Sheet builds the foundation to grow documentation based on needed track side changes.

Often, in our attempt to find elusive speed, the changes made at the track make the car go slower and sometimes harder to drive – even then it is crucial that changes are documented fully. Over time, the so called adjustment mistakes will clearly display a pattern that allows you and your team to increase your learning curve. Information is always good even when the documentation records negative results.

Be sure to assign a very responsible crew member that you can count on to make notations each time the car hits the track. When a chassis change results in a dramatic improvement it pays to make extensive notes and “flag” such set up victories for quick future reference. Filing your Chassis Set Up Sheets is key as well and it is a giant time saver to have a database of information on file to help prepare your car for a return visit to the same track.

Utilizing a Timing Sheet will provide session lap times that can be quickly reviewed. Often, a car might be blazing fast on lap 1, 2 and 3 but then fall of at the end of a practice session. A short run set up might be great for qualifying and notes will help you to decide. By recording your lap times during each and every session your team can find patterns allowing for discussion and proper decision making. Your Timing Sheet can be stapled to your Chassis Set Up Sheet at the end of a run so you can analyze the changes made and couple the set up information with real time speed information.

You can Download the JOES Timing Sheet at the JOES Knowledge Center http://www.joesracing.com/kb/index.php

In addition to lap times, tire temperature information will allow your team to fill the set up informational database with a complete package of repeatable documentation. Tire Temp Sheets expand your information package - viewed in conjunction with your Chassis Set Up Sheet and your Lap Time Sheets gives your team planning tools to consistently find more speed. Once found, your speed secrets should be written down each and every time in a common format that allows for a sustainable documentation process.

Tire Sheets and accurate tire temps are one of the few "Crystal balls" found in racing. A balanced set up can be obtained by tracking tire temps and making adjustments to find the set up that utilizes all four tires to their maximum capability.

You can Download the JOES Tire Sheet at the JOES Knowledge Center http://www.joesracing.com/kb/index.php

Quality documentation provides a focused format resulting in team discussions that are based on history, facts and real world experience. Writing down your set ups and track side changes, with support of Timing Sheets and Tire Sheets, saves time. The small investment in time for documentation is more efficient in the long run. Creating documentation in real time and “as you go” is the only way. Trying to re-create documentation at a later date leads to errors as our memories fail and important details are forever lost. Slow down to go fast and cultivate the discipline to “construct” your documentation as you go. Waiting until later makes the documentation process a chore – doing it now becomes a good habit that is a required element that fits naturally into your regime allowing for sustainable positive action.

Driver feedback should always be recorded and be a vital component of your documentation process. Make driver feedback notations and record the changes made to the car before it goes out on the track for the next practice session. Staple together your Chassis Set Up Sheet, Timing Sheet and Tire Sheet from each session and you will have instant access to vital information when you need it most.

Over time, your library of available recorded information will become the go to resource and you will establish your own baselines and rule sets. When an “ah ha” moment occurs due to a successful adjustment, be sure to flag those sheets and spend extra time documenting driver feedback. You never know what the future holds and a successful fix to a chassis handling problem today may apply to another track or circumstance. The best documentation evolves with your team and becomes a pivotal tool that participates in the ongoing growth of your orchestrated racing program.

Go Forward – Move Ahead
Jeff Butcher
Courtesy of JOES Racing Products
5/1/11

Note: You can download our growing library of organizational sheets for free by visiting the Knowledge Center at joesracing.com You can Download the JOES Chassis Check List Sheet at the JOES Knowledge Center http://www.joesracing.com/kb/index.php

Master Cylinder Math Explained

2011-05-13T14:52:00.000-07:00

Going faster creates a need for stopping faster. Efficient braking is based on choosing the right components and matching the proper combinations will result in a brake system that works in conjunction with the specifics of your car, track and driver style. It is highly recommended that you work with your brake company engineer to assist you in building the right combination to tailor a system for your application. Since pad compound, rotors, calipers and master cylinders all work together in relation to car weight, speed and track characteristics, it makes sense to think of your brake system as a package. Each brake component relates to the other braking variables and an individual change may necessitate the need to reanalyze your entire brake system in your effort to achieve a balanced clamping force on your car.

A Billet Clamp On Reservoir Mount allows you to mount your brake fluid reservoir at a high point resulting in improved brake bleeding. Remote mounting keeps unwanted heat away from your brake fluid.

We contacted long time brake expert Carl Bush from Wilwood engineering to help our readers understand the brake system. While I encourage you to consult your brake company engineer to build the right braking system, I also encourage you to learn how the parts interrelate. With your own knowledge base, education will allow you to better communicate your needs resulting in the best brake system possible.

How do you pick the proper master cylinder?

Carl Bush:
Master cylinders are an integral component in the brake system. They are responsible for sending the correct amount of pressure and balance to the brake calipers. But it must be remembered that they are only one component in a system, and do not function alone. Brake requirements for different types of race cars will vary by component and element. But all systems do carry a common thread. They must allow the driver to stop the car with comfortable leg effort while contributing to the overall handling and performance of the car.

How do master cylinders work?

Carl Bush:
A master cylinder is used to convert force from the brake pedal into the hydraulic pressure that operates the brake calipers. The amount of pressure generated is a function of the force being applied, divided by the master cylinder bore area. A 1” master cylinder has a bore area of .785” inches squared. For every hundred pounds of force applied to the master cylinder piston by the pedal pushrod or balance bar, that master cylinder will generate pressure equal to 100 divided by .785 or 127.4 PSI. By calculating the area in inches squared (bore x bore x .785”) for any master cylinder size, you can calculate how much pressure change would be affected by a bore size change.

A 7/8” bore master cylinder has a bore area of .6” inches squared. If we apply that same 100 pounds of force to the 7/8” master cylinder, using the formula 100 divided by .6, that same 100 pounds of force from the pedal will generate 166.7 PSI. A decrease in master cylinder bore area produced a proportionate increase in line pressure. This line pressure management becomes a key factor in setting brake balance.

Master Cylinder bore size is the element that affects pressure.

Jeff Butcher:
So Carl provides some great information about how master cylinder size works with your leg effort and brake system. How can we use Carl’s master cylinder bore area math to our benefit? Since my articles try to remove some of the engineering speak and present information into layman terms, I will try to expand on the math that Carl is illustrating. If you read all the way through you will see that the math is easy once you get a handle on all of the terminology. By understanding the basics you will have more data to make informed decisions.

Carl explains that a 1” Master Cylinder has a bore area of .785” squared. To get to this number you use the formula for Area which is: Area = 3.14 (Pi) multiplied by the radius squared. So you calculate the radius of 1” bore which is simply half of the diameter which equals .5” (half an inch). The result is that a 1” master cylinder has a radius of half an inch. You then multiply your radius which is a half an inch (.5) by itself so .5” X .5” = .25” or a quarter of an inch. .Multiply .25 X 3.14 (pi) and you arrive at Carl’s .785” area number. Basically, I just repeated what Carl said in an effort to make the math more simple and I bet the barrage of numbers made the calculation more intimidating and confusing? It’s ok – we will get to a simple way to look at the master cylinder math and going through the steps will make the process easier to understand.

Another way to explain Carl’s math uses a 7/8” master cylinder as the example. We will do the calculation and show our work to reinforce the math for calculating bore area.

Bore = 7/8”

7 divided by 8 gets us the decimal equivalent = .875”

The Radius is .875” divided by 2 = .4375”

.4375” Multiplied by .4375” (Squared) = .1914”

.1914” Multiplied by (Pi) 3.14” = .6” - which is the answer Carl explained above.

With the progression towards understanding the math we can do take the steps the easy way. Use Carl’s magic formula of Bore X Bore X .785” (.785 is the magic number that simplifies the above equations as it simply pre-calculates the squared business relating to Pi in advance). So a 7/8” bore is .875” X .875” X .785” = .6” Bore Area. It turns out you can use the number .785” and multiply it by ANY Bore X Bore as the reusable number of.785” is a derivative of Pi and it is a repeatable math number that can be used with any and all bore sizes. So, the complicated math shown relating to Master Cylinder Bore Area can be simplified. Now we have taken another step towards understanding.

Bore X Bore X .785” - you can always use .785” in the equation.

Let’s check with the Easy 1, 2, 3 method:

For an example 7/8” Bore master cylinder the Bore Area math is:

Step 1 – Convert the fraction Bore to a decimal by dividing the bottom number in the fraction into the top number.

7 divided by 8 = .875”. 7/8” is the bore marked on the outside of the master cylinder and .875” is the decimal bore equivalent of 7/8”

Step 2 – Multiply the bore diameter (our example is .875”) by itself which is the same as bore squared.

.875” X .875” = .766”

Step 3 – Multiply the bore squared result from step 2 (.766) by the reusable number (always .785 with every master cylinder size – you can count on .785 to work every time with every master cylinder size).

.875” X .875” = .766

.766 X .785” = .6

.6 is the Bore Area for a 7/8” Master Cylinder!

The EASY 1, 2, 3 Bore Area calculation is right here!

Our example was for a 7/8” master cylinder. Now you can use the bore size on your car and substitute your actual numbers to come up with your Bore Area, front and rear, by following the 1,2,3 calculation above. Now that we have our Bore area numbers of .6 for a 7/8” master cylinder and .785” for a 1” master cylinder what do we do next? Carl states that a smaller master cylinder bore creates more pressure with an equal amount of force. A 1” master cylinder creates 127.4 PSI as compared to a 7/8” master cylinder which is 166.7 PSI based on your foot making 100 pounds of force at the master cylinder. It is important to consider that the smaller cylinder makes more pressure but the smaller bore will move less fluid. More travel will be needed to make up for the reduction in fluid moved by a 7/8” master cylinder as compared to the larger 1”. Carl explains further in the next section.

Utilizing a bolt on caliper mount ensures that your calipers are square to the rotor improving pad wear and braking efficientcy.

How do fluid volume and leverage come into play?

Carl Bush:
While a change in master cylinder bore size affects a pressure change, it also changes the amount of pedal travel realized to add the additional stroke needed to displace enough fluid to move the caliper pistons. This volume ratio plays an important role in the clamping capability of the caliper, and leverage that the driver has to generate that clamping force. The ratio between the caliper and master cylinder is a function of the net effective caliper piston bore area divided by the bore area of the master cylinder. To compare these ratios and do the calculation, you must start with the total piston area of the pistons in one side of one caliper.

A front brake set using four piston calipers with 1.75” diameters will have a net bore area of 4.8” inches squared as each 1.75” diameter piston has an individual bore area of 2.4” inches squared.

(Jeff’s Easy Math works for caliper piston bores too – 1.75” X 1.75” = 3.06” X Reusable Number .785” = 2.40” X 2 Pistons = Carl’s Net Bore Area of 4.8”)

Carl Bush-continued:

By running the formula, the leverage ratio between a 7/8” bore master cylinder and the 1.75” four piston caliper will be equal to:

Effective Caliper Piston Area (4.8) / Master Cylinder Bore Area (7/8 which is .6) =

4.8 / .6 = 8 for an 8:1 ratio.

The driver leverage is then determined by multiplying the Pedal Ratio x the Caliper Piston Bore to Master Cylinder ratio. (Note from Jeff: “The pedal ratio is marked on your pedal assembly when you buy it or use the Pedal Ratio Drawing shown”).

Carl’s Example:

Pedal Ratio (6:1) x (Piston Bore (4.8) / Master Cylinder Ratio (.6) results in (8) = Driver Leverage (48:1)

6 x (4.8 / .6) = 48:1

You can substitute any number of piston bore combinations with master cylinder sizes with any pedal ratio to determine the driver’s actual brake leverage.

For fun Carl has given you the answer to the test with this chart.
Common Caliper Piston Size Diameter / Area

Diameter, Inches 1.12 1.25 1.38 1.62 1.75 1.88 2.00 2.38 2.75 2.94

Area / Piston, Inches Sq .99 1.23 1.48 2.07 2.40 2.76 3.14 4.45 5.94 6.78

Common Master Cylinder Bore Sizes / Area

Diameter, Inches .62 .75 .81 .88 1.00 1.12

Area / Piston, Inches Sq .31 .44 .52 .60 .79 .99

By changing to a 7:1 ratio pedal (from the 6:1 shown in Carl’s Example), the driver would then realize a final ratio of 56:1 with the same caliper and master cylinder (Jeff’s math 7 x (4.8 / .6) = 56:1). Consequently, a 5:1 pedal would only give the driver a 30:1 ratio (Jeff’s math 5 x (4.8 / .6) = 30:1). If we compare the front leverage ratio to the rear leverage ratio on any given car, this tells us the front to rear static bias capability of the car.

Pedal Ratio is determined by dividing length "A" by lenght "B". The amount of force at "F" determines the force to the master cylinders.
Now that we know the math, can you explain a common set up for our readers?

Carl Bush:
A common set up that could be found on a weekly show short track asphalt car is to use the example above with 1.75” piston calipers on the front with a 7/8” bore master cylinder, and a pair of 1.38” piston calipers on the rear with a 1” master cylinder. A 6:1 floor mount pedal ratio is also common. We have already determined that the 1.75 pistons with a 7/8” master cylinder and a 6:1 pedal will give the driver an overall brake leverage of 48:1 on the front. If we use the same formulas with the 1 3/8” piston calipers and 1” master cylinder on the rear, that produces a total driver’s rear leverage ratio of 22.75:1. When we compare the 48:1 ratio in the front, to the 22.75:1 ratio in the rear, we see that the car will be baselined with a front to rear static leverage bias of 67.8%, as long as the balance bar is centered and equal force is being applied to both master cylinders. You can substitute any combination of parts and their sizes to determine the exact influence they will have on the baseline static bias ratio.

Four piston calipers can usually be found with piston sizes from 1.125" to 1.875". The area of two pistons on one side of the caliper determine the calipers influence on clamping capability.

How do we use pressure to determine brake bias?

Carl Bush:
Although racing with a perfectly centered balance bar is the ideal goal, it seldom happens in reality. Besides, one of the advantages in using an adjustable balance bar is having the ability to adjust that leverage to optimize handling and driver comfort on track. Trying to measure the post-race leverage split at the balance bar is difficult and unrealistic. However, using pressure gauges to measure pressure differentials s at any given balance bar setting is relatively simple. The brake gauges will show the actual pressure split in the car based on the balance bar adjustments made by the driver. Those pressures can then be multiplied by the effective caliper piston bore areas to calculate the last on-track static bias settings.

Calipers such as this metric replacement only have one piston on one side. The calculation of their clamping capability still uses the same formula.

Going back to our (common set up) example, if we apply 50 pounds of leg force against a 6:1 pedal, we will generate 300 total pounds of force against the balance bar. If the balance bar is perfectly centered, it will distribute that force equally to each master cylinder. With each master cylinder receiving an equal force amount of 150 pounds, the 7/8” master cylinder should produce 250 PSI (Jeff’s math: 250 PSI comes from 150 divided by .6 which is the 7/8” master cylinder math result) while the rear 1” master cylinder produces 192 PSI (Jeff’s math: 192 PSI comes from 150 divided by .785 which is the 1” master cylinder math result). In practical use of gauges, you can use any level of effort and pressure for your comparisons. The end result will be the same.

When the front pressure of 250 PSI from the 7/8” master cylinder is multiplied by the 4.8” inches of caliper bore area of the front 1.75” piston front calipers, we get a front clamping force of 1200. On the rear, we will have 192 PSI x 2.97” caliper area or 570 pounds of rear caliper clamping force. When comparing the these front to rear clamping force total in the same way you would compare wheel weights for balance, we would see that this car has a total of 1770 pounds of caliper clamping force at these line pressures with 1200 pounds or 67.8 % on the front. It’s that same static bias ratio that was measured using the overall driver leverage ratios.

Now, if every car and driver had the same braking requirements and pedal feel preferences, we would never need to adjust anything. But, every car and every driver are unique and adjustments will get made.

The ratio examples that have been used here are very common in many short track asphalt cars. But your car, for a wide variety of reasons, may have quite different requirements. As a racer or crew chief, you can use these formulas to map the existing brake set up on your own race car, and then make calculated decisions when the desired handling or driver feel isn’t being delivered. The inability to reach the desired bias or driver’s feel of the pedal is the indication you will need to evaluate your component selection and consider possible alternatives. By using the formulas in these examples, you can accurately calculate what affects a component change will make to your existing baseline, and record those final ratios in your records to use for future adjustments and set up for any given track type or conditions.

Jeff Butcher
As you can see, using the experience of you brake manufacturer is very valuable. Still, when you breakdown the math it is not all that hard. By understanding the pressures, bore areas and ratios you can improve your understanding of the brake system. A thorough understanding will help you to make improvements to an existing car or transfer learned knowledge to a new car. Be taking the time to understand the basic math behind the braking system you can calculate and record winning brake set ups. Slowing down to do the math will help you to go fast.

Go forward – Move Ahead.

Jeff Butcher
JOES Racing Products
3/1/11

Nice Rear End

2011-03-15T10:44:00.000-07:00

Nice Rear End

Getting to the front often start with a good rear end. Today, there are many options and choosing the right rear end type for your team is the goal.

To help your team choose the correct rear end type for your car, I interviewed Frank Loverock of Quick Change Exchange. Frank manufactures ratcheting rear ends and differentiating rear ends and he has provided a wealth of information for this article. In addition, Randy Larsen of DPI added thoughts relating to the benefits of differentiating rear ends as well as his thoughts on the different styles of rear ends and other tips.

Rear Ends – A simple overview

A spool is a simple chunk of billet aluminum with axle splines. The spool is very durable and simple. Since the axles are solidly connected, a spool requires stagger to deal with the LR tire following the shorter radius at the inside of the corner as compared to the RR. When you push a car through the pits you see the LR tire skip as it catches up with the larger radius of the RR tire.

The Locker (Ratchet) allows the wheels to unhook one tooth at a time on corner entry. The “ratcheting” mechanics allow the LR to roll in the corner in conjunction with the RR helping to overcome the negative effects of stagger on corner entry. As soon as any amount of throttle pressure is applied, the locker (ratchet) locks up and performs like a spool. Both axles are locked together and when the power is put down a ratchet and a spool work the same.

Differentials utilize a series of gears that apply the power to each rear tire individually. Less stagger is required and if your stagger changes the differentiating action works to keep the handling characteristics of your car the same throughout the race. A differentiating rear end has moving parts that require regular maintenance. Quality gear oil is needed and performance can be changed based on the type of oil used. Coolers are highly reccomended when you run a differential style rear end unit.

Differentials apply power to each wheel independently and the need for stagger is reduced. The axles are not solidly connected together and internal gears apply power to each tire separately. The result is a rear end that compensates for stagger changes. The car is more consistent and self adjusts for changing corner conditions.

Racing differentials feature an aluminum housing for lightweight. Manufactures are always discovering new ways to improve performance while producing lighter weight parts. Unit's of today do more and weigh less due to design improvements and superior machining techniques.

Q & A

As compared to a spool – why is a locker a good choice?

Frank Loverock:

The benefit of a locker is improved corner entry. As you roll into the corner, without any throttle pressure, the car enters the corner and the effects of stagger are basically eliminated. Both tires roll in equally as specially designed springs control the ratcheting action. At entry, the LR is connected to the driveline and the right wheel ratchets forward creating an entry without effective stagger. The car never freewheels, either one or both rear tires are connected to the driveline. The instant you push the throttle the ratchet locks up and you drive both rear tires 100% just like a spool. A locker (ratchet) is a spool 90% of the time so it is a myth that you can run less stagger.

Randy Larsen:

A locker can help a car into the turn and reduce an entry push. The rear tires ratchet in a controlled fashion for a more stable entry. Since LR isn’t dragging entering the turn, drivers can drive in deeper. A locker becomes a spool as soon as the driver hits the gas so stagger settings are critical. Under power, the locker acts just like a spool so your tire guy needs to make sure that the stagger remains perfect throughout the race. Any change in stagger is going to be felt and loss of stagger often will create a nasty center push.

As compared to a spool – why is a differentiating rear end a good choice?

Frank Loverock:

On a circle track car, the RR must travel faster and further than the LR due to the larger corner arc on the outside of the track as compared to the inside. The differentiating action turns the LR at a slower rate helping the car to turn.

Differentiating rear ends offer great advantages but come with significant maintenance so a trade off is made. The benefit is a car that really turns. The rear end may drive the LR 49% and the RR 51% and the unit is always differentiating applying power as needed to the wheel that needs it most. Differentials never drive the LR and RR equally but rather compensate for the ever changing position on the track. In other words, differentials are always driving the appropriate wheel faster than the other eliminating the dragging of a tire down the straight away. The faster turning of the outside wheel gets your car through the center with less dependence on stagger. Spools and lockers drag one tire if you are running even a small amount of stagger.

Randy Larsen:

A differential gets you through the center allowing the car to turn freely setting you up for a straight and powerful exit launch. The differential action allows you to run the low groove one lap and the high groove the next as the gear mechanism compensates for the change in corner radius. If your stagger changes - the differential will make up the difference so you car stays fast the entire race.

Since the differential gets you through the center, you can adjust your set up for a tight launch off the turn. The differential gives you more chassis set up options than a standard spool and the driver feel through the center is vastly improved. When your stagger changes a spool driven set up is negatively affected. The torque sensing action of differential units allows the car to roll freely through the center and compensates for changing stagger.

What improvements in design and quality have been added to rear ends?

Frank Loverock:

Superior machining operations create parts that mate together precisely for smooth long lasting operation. Better materials coupled with sophisticated heat treating processes create unparalleled longevity and performance. Rear end units last longer and work better through exploitation of modern science. Knowledge from the past is applied to what we build today. Historical influence is partnered with advanced modern day processes creating improved product at fair pricing.

Randy Larsen:

In racing, heat is nearly always the enemy. New manufacturing processes have allowed components to be light where needed and designers can pinpoint the need for mass at critical areas. Heat treating and CAD software have allowed differentiating rear ends to be optimized as compared to past designs. The optimization results in consistency. Units manufactured today limit and compensate for heat expansion efficiently resulting in enhanced performance.

What rear end types do you recommend to experienced racers?

Frank Loverock:

For experienced teams, a locker or a differentiating rear end is a good choice. It comes down to driver feel. Experienced teams are better suited to handle the added maintenance and often have larger budgets. The benefits of advanced rear ends, provides choices for experienced chassis gurus. With better feel, drivers can often get more speed by utilizing a rear end that matches their style, track and set up.

Close tolerance machining processes allow rear end units to do more at lower temperatures and with more longevity.

What rear end types do you recommend for beginning racers?

Frank Loverock:

For beginning racers I think a spool or maybe a locker is best. It all depends what the new driver wants to get out of their career. If they hope to move up to the top NASCAR divisions then gaining a feel for a locker becomes more important. All the top NASCAR series require lockers so gaining experience is a factor. Lockers require maintenance but the rebuild cost and time is manageable.

I strongly believe that a beginner should keep things simple so the spool is a good choice. As beginners gain experience and understanding grows, then experimenting will help their learning curve. Trying new things will help beginning teams to learn what different adjustments can accomplish. Starting from a simple proven baseline speeds the learning curve. As knowledge increases and drivers become more confident, then replacing the spool with a locker or differential creates a situation where teams can learn and feel the benefits from trying out new ideas.

Coolers, Oil & Maintenance for lockers and differentials?

Frank Loverock:

A rear end cooler is highly recommended and the best quality gear oils add to performance. Our group has designed synthetic oils that are specifically engineered for the friction created by the differentiating action. The test time to create exceptional gear oil is unbelievable and regardless of the gear oil you choose, quality is a must.

Randy Larsen:

Gear oil choice for differentiating rear ends is an area where spending more is always the best choice. Inexpensive gear oils translate to worn out hardware. We recommend top quality gear oil such as Joe Gibbs. We recommend coolers as reducing heat increases longevity and consistency.

Both Frank and Randy recommend servicing Lockers and differentials twice a year based on 25 races under 100 laps. A once a year rebuild “can” be okay. But, stretching service intervals can result in diminished performance. Personally, I would go with twice a year, as a minimum, based on the 25-100 lap race schedule. A locker requires less maintenance as compared to a differential. Ensuring that locker springs hold their designed rate is a must.

How has the use of rear end units changed?

Frank Loverock:

Experience has allowed us to manufacture 6 different springs’ rates for locker units. Stronger spring rates give the car a tighter feeling on corner entry. Lesser rates free the car up. Individual drivers often like different feels so over time the need for multiple spring rate options have evolved. Manufacturing processes have improved allowing for all rear end units to create more corner speed. Spring technology allows for ratchets to be custom tailored for specific track conditions or driver styles.

Locker springs are manufacutured in a variety of rates to control the ratcheting action for the perfect driver feel on corner entry. A stiffer spring creates a tighter feel on entry and correspondingly a lighter rate spring creates a more free feel.

Randy Larsen:

Tolerances control has made giant leaps forward. Differentiating rear ends perform better and last longer. As the manufacturing techniques have improved, engineers can find more speed with components that mate up more efficiently. As the science improves, doors of creativity open. Engineers can take advantage of creative ideas as they can count on sound manufacturing processes that produce components that perform every week.

What other tips relating to rear ends would be important for our readers?

Randy Larsen:

Proper venting is paramount to rear end performance. 1/2” hose and a minimum of 3/8” NPT fittings will allow sufficient air volume and rear end breathing. Small hose can cause pressure build up and unwanted problems. Be sure to route your vent line so that oil can drain freely. Kinks and dips in the line will cause oil to pool up preventing proper venting. The vent should be at the highest point possible above the housing. The hose should be routed as straight as possible to avoid areas in the hose where fluid can pool up.

Frank Loverock:

We are constantly developing technology and lighter weight differentials are the result. Differentials differ from lockers as they are free from locking and unlocking.

The differential allows you to run less stagger, about half as much as a spool, depending on the track. Differentials are very forgiving in relation to stagger changes as the gear mechanism is constantly adjusting to the current condition resulting in handling characteristics that stay the same throughout the race.

Jeff Butcher:

All rear end types offer positive choices. The simplicity of a spool is very often fast, inexpensive and maintenance free. Heat is less of an issue and a rear end cooler is optional at many tracks.

The locker creates stable corner entry. Coolers are needed and correct locker springs will speed your car up. You sign up for maintenance but less is required than a differential.

The differential can do many things to add to speed. In exchange for the stagger compensating differential action, heat is created and since there are more mechanical parts - wear and maintenance need to be considered.

In the end, all three types consistently win races. It is not a question of right and wrong. Choosing the correct rear end is specific to the needs of each team and the goals that they have. My teams have won plenty of races with a spool and if you are on a tight budget the simplicity becomes more important. It was fun to win with the free entry of a locker which is often a great choice. At other times the differential will power you to the front and that great feel in the center is something that drivers always enjoy. Teams that choose rear ends based on their own needs are making the “right” choice. In racing, bolting in speed is a myth. Having a nice rear end is always a good thing regardless of the type you like to run with.

Go Forward – Move Ahead
Jeff Butcher
Courtesy of JOES Racing Products
2/1/11

Panhard/J-Bar

2011-01-17T09:46:00.000-08:00

Adjusting the Panhard Bar or J-Bar always generates feedback from the driver – sometimes good and sometimes so bad that the crackle from the driver sounds like the speakers blew at an AC/DC concert. Even on TV you hear about 1/8” adjustments during Cup races that take the driver from waving handfuls of steering wheel to driving with one hand. Of course, the same team can try to cure a small tight feeling and raising the bar the same 1/8” can make the car junk. It seems the entire chassis package revolves around what can be a very sensitive adjustment.

So why is the Panhard/J-Bar so sensitive and how come drivers can nearly always feel even small adjustments? I mean the bar is simple enough - all it does is connect the chassis to the rear housing locating the rear end laterally. It’s just a bar with a rod end on each side yet the height and angle seem to do so much.

To help understand why the Panhard/J-Bar is so sensitive it pays to think out all relationships that change based on how it is located. First off, the front roll center gets involved as the roll axis (the line drawn through the front roll center extending through the rear roll center) is affected. As you lower the Panhard/J-Bar you also lower the roll angle and the center of gravity gains leverage because the distance from the roll axis line and the Center of Gravity is increased. The result is a car that rolls more due to the leverage increase and the added distance from the CG allows for roll around an arc with what is basically a larger diameter.

As you raise the roll axis the distance from the Center of Gravity is less and the car rolls less. In this case, there is more of a direct force applied to the right rear tire. Seems so simple yet there is more to think about.

The rear spring rate controls roll so there is a correlation between rear spring rate and the Panhard/J-Bar. In essence, as you run more rear spring the effect of the bar changes – or does it? That giant sway bar controls roll as well. All the things that control roll perform their function in a somewhat progressive fashion and the timing of the control is slightly different. This is the point in the story where engineers and data acquisition get fun but since it is always my goal to remove engineering speak here there are many things to consider. Since the variables are many, the answers change depending on entry speed, banking, braking, track grip, tire grip, balance, aero and the like – no wonder engineers make the big money and are such snappy dressers.

Whenever I face many dynamic variables that change depending on when and where the car is in the corner it is my goal to find a way to simplify in a fashion that allows me to make real world changes at the track. This is where basic understanding of the hardware can help you to draw your own conclusions.

A low Panhard/J-Bar promotes roll. A high one relatively resists roll. The Center of Gravity in the car is the same regardless if you have 100 lb springs or million pound springs. Springs are progressive. A 500 lb spring compressed one inch stores 500lbs. The same spring compressed 2” stores 1000lbs. So the springs compress in roll and in squat. Great.

The Panhard/J-Bar locates the rear end laterally. In squat it does basically nothing. As an example; a drag car is designed to go in a straight line. The drag car only experiences squat (of course there is engine torque but humor me and imagine just squat). In this example you could mount the Panhard/J-Bar on the roof or on the ground and the squat will be pretty much the same.

In our cars that turn left, the Panhard/J-Bar centers the rear end on the straights and then applies force laterally as the car transitions into the corner. Based on the height the springs store energy and as we exit the spring energy is released at a rate in conjunction with the Panhard/J-Bar. A high bar transfers load quickly and a low one takes longer due to the added distance between the Panhard/J-Bar and the Center of Gravity – well at least in an apples to apples situation.

So – the result is we can change the “timing” of roll as well as the loading of the lateral force of the Center of Gravity by adjusting the Panhard/J-Bar. Fabulous – but how much and when do we raise the Panhard/J-Bar verses adding more rear spring rate? There is not an answer to this question unless your car has a 48 on the side. In the end, as you have more grip though a better racing surface, tire compound and more down force then a higher Panhard/J-Bar will transfer loads in a more direct fashion creating quick and sporty reactions. Of course track banking and car speed get tossed in the variable bucket too.

If your track is bumpy, worn out, small and has little banking then maybe you want to slow down the reaction of the car and smooth things out with a lower Panhard/J-Bar. Since I grew up in the Northwest all of our tracks were worn out and we raced on top of shiny rocks. I know I ran Panhard/J-Bars at least a full inch lower, on average, than my competition. We managed to win some and we always were good on the long run so in general a lower bar made up for reduced grip and minimal down force as most of our tracks were small and flat.

Since the Panhard/J-Bar is such an important locating device it is critical that the hardware is solid. Any flex creates unpredictable variables resulting in a car that is erratic. The hoop style shown adds rigidity and creates a solid feel for the driver.

Then we get into Panhard/J-Bar split and reverse split. There are a lot of thoughts on this topic. I hear about how teams think the rear end moves left when the right side of the Panhard/J-Bar is higher than the left. Well – the rear end is stuck on the ground and what is really happening is that the frame and body are moving to the right. Your team needs to think about the trailing arms and the rear steer in relation to the amount of split you are running. You also need to think about your shock angles. If they are perfectly vertical on your coil over car then when the body/frame moves right not much happens as both coilovers shorten by the same amount. If you have the top of your coil over tipped in then as the body/frame moves right you are losing diagonal weight as the car rolls and then gaining it as it rolls back. With tipped in at the top coilovers, if you run reverse split, the body/frame moves left and the LR shock gets more upright adding diagonal weight percentage.

Still, there are many times when you add reverse split that the car turns better even though there is potentially more diagonal through roll. The big reason is that the Panhard/J-Bar was probably too high to begin with and side bite is lost. The car skates in this scenario so lowering the bar creates more grip. More grip allows the driver to feel more secure so he can simply turn the car to the bottom instead of skating up to the second groove. Sure – you can think about how reverse split encourages the rear end housing to be pulled into the track and how standard split (higher on the right side) pulls up on the rear end housing. Last I checked gravity is the same and regardless of how uphill you run the Panhard/J-Bar so I doubt the rear tires will ever fly off the ground due to Panhard/J-Bar angles.

With standard split or reverse split rear steer comes into play. You can use rear steer to your advantage but remember to think past direction the housing moves through roll. Keep in mind that the housing goes the opposite way as the chassis unwinds and sometimes the opposite and equal reaction is more important than the intended action.

A frame side Panhard/J-Bar mount that adjusts quickly can maximize practice time ensuring you have every chance to dial in the car. The slider version allows for precision locating and increments as small or as large as you need.

Even so, there is still more to it. The goal is to get the most out of everything. Maximum down force in combination with soft tires creates an opportunity. Of course, you may have a sway bar in the car the diameter of a sewer pipe so how do we balance the Panhard/J-Bar in association with a ton of rebound in the front shocks and a sway bar that locks down the nose? Again, there is not an answer as “all” of the variables have to come together to create the right feel for the driver.

A J-Bar bracket with a slotted adjustment allows for quick changes. A wide adjustment range with slots verses holes will help your car to find every ounce of speed.

Instead of me telling you the answer to the pop quiz I prefer to write down my thought processes. It makes little difference if you agree – it makes a lot of difference that you develop a consistent system that lines up with the variables that you face. Honestly, the magic 48 has mastered this systematic approach. Sure – they make a ton of horsepower but in the end the 24 and 88 have the same junk. The 48 kids have balanced the HP with the aero, the shocks, the sway bar, the available grip and have come up with a system that allows Jimmy to run aggressive rear weight and ideal Panhard height. I don’t have inside knowledge - but I “know” that Jumping Jimmy, whether y’all like it or not, can run aggressive set ups that push out every ounce of grip cuz Sir Knaus has this formula flat figured out. He approaches the system the same way every week and eliminates as many variables as possible. The result is an edge that allows his team to be better than team mates that are in the same shop. The benefit is that Jimmy can get a little more due to the communication derived from their proven formula that features the Panhard height as a major component in their magic math.

Raise the Panhard/J-Bar when:

1. There is a ton of grip available.

2. When you have high amounts of down force.

3. You have high banking and smooth transitions.

4. When the car is solid and easy to drive deep into the corner.

5. When the driver can pull down a groove at will.

Lower the Panhard/J-Bar when:

1. The driver doesn’t like the corner entry feel.

2. The car won’t stay on the bottom.

3. The track is bumpy or has little grip.

4. When the car feels fast for 2 laps then drops off considerably.

5. When left side tire temps are low.

Think opposite when:

1. The driver says the car is tight yet you have thrown many adjustments at the car that should have made a noticeable difference – none of those adjustments are working. This may be a time when a lower Panhard/J-Bar can add more positive rear steer through added roll helping it to turn in the center. A gain in side bite would be the goal increasing overall grip giving you new chassis adjustment options created by this new baseline.

2. The car needs more side bite so the driver is timid with the steering wheel on corner entry so he misses the apex making him believe the car is tight. Pay special attention if the driver complains that the car snaps loose after being tight in the center as this “can” be an indication that lower is better.

3. When you keep raising the bar to help the car turn and there is little change.

4. Panhard/J-Bars are so easy to move that sometimes it pays to simply raise and lower it a small amount and just use the trial and error method.

While a simple device, the Panhard/J-Bar is basically the hardware that connects the Center of Gravity to the ground thus increasing the importance. Getting the adjustment just right is the key to winning. So when you ask me how high you should run your Panhard/J-Bar my answer will be, “I don’t know – ask the driver”!
Go Forward – Move Ahead
Jeff Butcher
Courtesy of JOES Racing Products

12/1/10

Clear Vision

2010-11-18T09:59:00.000-08:00

Back in the day of no helmets and open car cockpits the only need for mirrors was to see if drivers had their Dippity Do hair gel smoothed perfectly on their ruggedly handsome heads. Luckily, I only know about that hair product because my Dad would take a handful and smear it on his once full head of hair – not me! Today, drivers are strapped in their cars with head restraint systems, wrap around head braces, full face helmets, Nomex hoods, window nets, and blind spots that would make Helen Keller a better than today’s “blinded” driver. She could be competitive and prevail over sighted drivers as she was comfortable utilizing the drive by brail system. Sighted drivers have to overcome being out of their element and overcome the mental discomfort created by the limited vision found in cars of today. Helen had no such limitation and subtle bumps of brail came naturally to her. A driver using brail finds much bigger bumps, zero subtly and hard crash resulting in the need for a cane the following day – a cane for injured people, not a white one.

Often I have heard drivers say they would rather not have mirrors as they get annoyed at those few drivers at every track that drive with the mirror to fill up the grove instead of simply driving as fast as they can. Some old school drivers think that mirrors should be removed as they feel as if they take away from their driving skills and they don’t need them. These drivers think if a competing car is up to their door then they will see them. If the car is not in their peripheral vision then it is ok to cut down into the turn. I think this old school thought may have been true at one time. Today it is so hard to see due to needed safety improvements and new thinking needs to be considered even by experienced racing veterans.

Safety advances are clearly the right choice but they do have an impact on vision making the need for mirrors a top priority. More vision means more safety and mirrors are an aid and not a crutch.

At Daytona and Talladega the Cup stars accept that blocking and mirror driving are simply part of the deal. At local short tracks blocking may happen but, to me, the safety aspects of proper vision outweigh the drivers that break the unwritten rule about using mirrors to intentionally drive in an erratic pattern in an attempt to keep pursuers at bay. The reality is that in today’s modern stock cars it is so hard to see that the need for mirrors is very real. Competition is so tight that mirror driving isn’t as easy as compared to the days when drivers had full head movement, open face helmets and seats that stopped at their shoulders.

Modern day drivers have so much going on in their cockpits that it takes full concentration to look forward to hit their marks. Sure, a few guys can block by mirror driving for a few laps but in return their lap times become so slow that they get passed eventually anyway. A few bad apples will always mirror drive but those types are rarely the guys that are in the front week in and week out. Besides, on a quarter mile short track it only takes a few blatant mirror driving moves and the trailing driver with a faster car has a chrome, well plastic, horn that trumps mirror driving. A quick rap on the bumper gives the mirror driver plenty to think about. Mirror drivers have plenty of time to think while being towed off the track when a veteran shows them how the bumper on a faster car functions.

Used properly, mirrors are a safety device that should be employed extensively. If you look close at the Cup cars on TV they nearly all have clamp on spot mirrors on the driver side window opening. Large wide angle rear view mirrors help drivers to know what is going on behind them. With the knowledge that a car right on the driver’s bumper competitors know that full concentration is required. The awareness of close action is a safety necessity. If the track is clear behind drivers can be mentally fresh when it counts as they can take a small mental breath if they know they are not being dogged from behind. With a clear rear view mirror drivers can experiment with different lines in the never ending quest to find more speed.

Many short track teams employ radios and spotters can be very helpful in keeping drivers informed. The spotter’s job is to look ahead and give advance warning of on track trouble. In addition, spotters can help with strategy, discussing chassis adjustments and of course they can be vital in helping drivers to know if a competing car is inside or outside. For drivers, it is quite comforting to hear that it is “clear” all around. While spotters can be an important tool it still comes down to the driving feeling what is going on around him and the decision to pull down at corner lies squarely with the driver. Many race series do not allow radios and the drivers are solely responsible to be aware of their surroundings. Mirrors play a vital role in helping drivers know when it is safe to go low or take the high groove.

A quick glance to the side view spot mirror provides instant information and a good wide angle spot mirror provides a clear view providing instant real time information for the driver to act upon. Increase vision improves speed and cuts down on accidents. Corner entry accidents always create controversy and in the end if a driver can prevent an accident then every tool available should be utilized.

A spot mirror on the drivers side will help you to feel cars around you. A fraction of a second gives you added confidence entering the turn when you know you are "clear". Cup stars may mirror drive but they have the luxory of just getting out another car out of their stable of 20. Saturday night racers usually have one car and when it is torn up the concern is about cost and time to repair. Cup drivers don't even think about cost, time and damage and they have an entire shop getting the next one ready. Mirrors prevent alot of damage on Saturday night if used properly.

Wide angle rear view mirrors are equally as important. Adjusting the mirror to cover blind spots helps drivers to know what is happening around them without the assistance of a radio spotter. While spotters are invaluable – instant information provided by a quick glance allows drivers to make better decisions. Whenever I hear a driver throw their spotter under the bus after a wreck I wonder if a glance to the mirror could have saved a wreck. There is little doubt that stock cars with all the safety gear have limited vision and drivers can only see clearly through the front window. Just about every other view is a blind spot. The side view and vision out the back are severely limited and good mirror installations expand the drivers viewing area immensely.

Wide view mirrors that clamp on can be positioned perfectly eliminating most blind spots. A variety of sizes are available. Glass mirrors offer the best view and multiple bracket options allow you to get the mirror just where it is needed.

I think there should be a rule on every stock car including big time NASCAR racing that requires the use of a Lexan spoiler blade. A spoiler blade made from aluminum prevents trailing drivers from looking ahead through the windshield of the car in front of them. A clear plastic spoiler blade greatly enhances vision allowing drivers to see further ahead. Clear spoilers are a low cost safety measure that should be applied at every track. Why clear spoiler blades are not used on NASCAR Cup cars, Nationwide cars and Trucks is beyond me as the added cost is zero and the vision improvement is dramatic.

Ken Schrader spends a lot of time short track racing. I recall a time when he was driving a late model up in the Northwest and in the drivers meeting he was very vocal explaining to the officials and other drivers the need for Lexan spoiler blades. Schrader was a credible voice and at the time most of the cars were using aluminum blades. After his drivers meeting talk clear spoiler blades became the norm helping to make the Northwest series safer.

Clear spoilers help the driver behind to see through your car helping to avoid your car being pile drived if there is a wreck in front of you. Clear spoilers are inexpensive and they have zero drawback. If you ask me all series should mandate a clear rear spoiler blade.

There are a variety of mirrors available on the market and the clamp on versions mount in seconds. Easy adjustment and mirrors that can deal with vibration are a must. Once adjusted, simple locking mechanisms hold mirrors in place ensuring that drivers can count on clear vision. Clamp on mirrors offer the added advantage that the clamp mount allows for easy movement to provide for perfect placement. Weld on brackets commits the mirror location resulting in a compromise in vision. Clamp on brackets can be loosened is seconds and the perfect mounting location can be found easily and without limitation. The lightweight aluminum construction components are and added benefit.

Using the right bracket will get your mirror placed exactly. Teams should spend the time to eliminate as much blind area as possilbe. With the driver strapped in, a crew member can move about the car while asking if the driver can see the crew member in the mirror at all locations. In just a few minutes vision can be drastically improved.

Using spotters for guidance instead of as dependence will expand sight lines to safely see your way through an entire Saturday night. Lexan spoiler blades will assist all race series drivers in looking ahead allowing them to identify trouble fractions of a second sooner increasing the chances of avoiding crashes. Perfectly located clamp on mirrors, coupled with their proper use, will give your team a safety advantage and will save tearing up equipment. Amazing new safety gear requires new thinking and the ability to see and feel through your mirrors takes only a little vision.

Go Forward – Move Ahead
Jeff Butcher
Courtesy of JOES Racing Products
10/1/10

Weight Wisdom

2010-10-19T16:03:00.000-07:00

They say that the entire universe began as a tiny, and very heavy, object about the size of a marble. One day - this extremely dense marble like object decided to blow up and form every galaxy, planet, and star that is out there today. I am not sure if I totally grasp such a concept. What is clear is that I am watching way too much Discovery Channel and our focus here is making your car go faster. Still, if you could take a tiny sliver of that very heavy marble sized object from the universe on its birthday the little sliver of mass would be perfect for making your race car faster.

When building a new car, creating a Center of Gravity that is lower than your current car will allow for more speed. Physics demands that a lower Center of Gravity will create more grip on an object (racecar) that is going fast in a straight line and then, for reasons that are obvious to drivers, the object (still a racecar) suddenly needs to move violently left.

If you had material that was extremely dense and heavy such as a tiny chunk from the marble like object that created everything, you could use this heavy material to make your car consistently faster. Lead is commonly used to balance out racecars because it is dense, melts easily and is relatively inexpensive. The melting point of lead is a mere 621.5 Degrees F and it well suited for molding to nearly any shape.

Lead is less than healthy though and fumes, grindings and over handling should be avoided. Food while working with lead is forbidden. Researching the web for proper lead handling is a great idea. After finishing your lead handling research, and fitting lead for your application, it is easy to add a quick paint job to your completed lead blocks to assist in reducing unwanted exposure.

Lead costs less than 2 bucks per pound. 1 Cubic Centimeter of lead weighs in at 11.35 grams and steel comes in at 7.85. In a perfect world, you could use tungsten for your car ballast which weighs in at 19.35 grams per Cubic Centimeter and is very safe to handle. Too bad tungsten has one of the highest melting points on earth at about 6170 degrees F. Tungsten costs about $13.00 per pound or more. Regardless of your ballast material, the earth element lesson is utilized to help illustrate a point. Tungsten weighs about 1.7 times as much as lead which means you could take up almost half the space with Tungsten ballast as compared to lead. The smaller mass allows you to build in more adjustability. A small sliver from the big bang marble of the universe would be really efficient – let me know when you find a supplier for the mythical and magical material.

While safe, tungsten is one of the hardest materials on earth making it difficult to work with. Maybe you can find usable chunks at a discount from a surplus company. If you have some Osmium or Iridium laying about this would make excellent racecar ballast – of course finding these elements might prove to be very hard and very expensive. Guys in black suits would probably fly in from Area 51 to see what is going on in your race garage.
The point we are making is that we want our racecar ballast to be located in the smallest area possible verses being spread about the car. We work hard and spend big bucks on light weight materials for our cars so that we can add ballast for adjustability. It pays to locate car batteries low and left. Dry sump tanks are best mounted far to the left. Anything that is required in the car should be mounted in the lowest possible position and as far left as you can get away with.

Example 1: Side Weight - The example above shows two hunks of lead on the left frame rail and 2 equal chunks on the right frame rail. Locating lead in this fashion might show desired weights statically on the scales but when you put the car in motion this car will be slower than a clone car that has lead located in a centralized fashion.

Super Modifieds take the low and left thought to an extreme and their Indy Car looks are only given away by the giant V-8 engine that hangs completely outside the car to the extreme left. Super Modifieds are very fast and they are incredibly lightweight, have a very low CG, have a ton of left side weight and have massive horsepower. The only thing holding them to the ground is the giant wing that controls corner entry and down force.

When mounting lead in your stock car you always want it low. Your goal is to reach the maximum left side weight allowed by your rules with the lead in a compact area. By placing the lead in a compact area your car can handle the weight with more efficiency.

If you place lead in the left frame rail and another chunk on the right rail then the car will not be as efficient and on paper it will be slower than the same car with the ballast placed in the ideal location. With improper positioning of the ballast the tires will wear faster, the shocks will get hotter and the maximum car speed will be less than if you placed the lead in a compact area. You may need to manufacture your lead in shapes to fit in the ideal spot between your frame rails.

Example 2: Center Weight - Our hypothetical car shows the lead from Example 1 moved to the center of the car. In Example 2 we have the exact same amount of weight and are at the legal minimum and the maximum left side percentage. The shocks, springs and tires are much more efficient due to the proper location and centralized layout.

Your goal is to have the lead low and built for adjustability. Filling the left rail and then filling the right rail gives you the static numbers on your scales that might allow you to write down the set up numbers aimed for. The trouble occurs when you put the car into motion. Having lead on the left and right rails creates a situation the motion is harder to control than if the lead centralized. The lead on opposite sides of the car creates a back and forth rocking force that must be controlled by the springs and shocks. Located properly, the back and forth motion is reduced as the lead is centralized and supported between the springs and shocks for efficiency.

To illustrate further, school has started and many of you are loading your children up with books, computers, lunches, IPODS and cell phones. All of these items go in their backpack which is centered between their two tiny legs. The weight is carried so that the mechanical leverage of the human body can most effectively hold the weight while utilizing the least amount of energy. To improve conditions for your kids, making the back pack lighter is the best option. I am certain that parents would not load their kids down with extra weight and then make them carry the weight outside of their body center line. Kids wouldn’t be asked to carry two backpacks with their left and right hands extended out away from their body center line. I doubt parents would feel the need to add weight to one back pack in an effort to make the back packs the same weight and increasing the overall load of their little ones.

Our racecars (babies!) feel the same extra work when ballast is spread out with some lead on the left rail and some on the right. Ballast needs to be centralized so that the suspension can manage the inertia and centrifugal force efficiently.

Example 3: Rear Weight - Placing lead behind the rear axle might read the correct percentage on your scales but placing lead behind the axle is not recommended. Weight mounted behind the rear axle will cause the rear tires to overheat quickly and the car will be difficult to control. Ballast should always be mounted between the axle center lines for maximum potential speed and efficient control by your springs and shocks.

Less weight is always the better answer for your racecar and extra weight should never be added to gain more left side weight percentage or rear weight percentage at the expense of the overall total. In other words, you should never run over the legal minimum weight to get up to the maximum left side weight or any other number for that matter. Run as light as the rules allow and if your car is below the maximum left side allowable weight then find something in the car to move left but never add weight above the legal minimum.

Locating components in your car properly can help you to maximize weight distribution for ultimate potential speed. the clamp mounts on this radiator mounting system allow you to slide the radiator as far to the left as your frame allows. This mount also adjusts up and down ensuring your radiator is fit properly in the car. Creatively planning the low and left mounting goal of all of your required car components will help your car get through the corners efficiently.

The minimum legal overall weight is always the most important number otherwise our babies (racecars) will get tired by the end of the race. Shocks will overheat and tires will give up - just like kids that are carrying back packs with too much improperly placed junk in them. For your car to go faster, less weight is always the correct choice. The weight you add in ballast form should be concentrated in one area to allow your car the most control over the entire race distance. Your frame rails are much smaller than the universe and it only takes a little pre-planning to properly place ballast keeping your team from being in outer space.

Go Forward – Move Ahead

Jeff Butcher
Courtesy of JOES Racing Products
09/1/10
http://www.joesracing.com/

Just Breathe

2010-09-14T15:51:00.000-07:00

Finishing races begins at the start – in the garage to be more precise. The adage of “to finish first you first must finish” begins with car maintenance and construction. More than once I have seen cars hit the track for the first practice session only to spill fluids all over the place. When the smoke clears, the result is usually a load of engine oil or gear lube all the way around the track. Usually, the leak is unknown to the driver and the mess always seems to be square in the middle of the groove.

Overfilling fluids is a common cause of leakage and often errors in the venting system create the trouble. Fluid management and proper venting practices are simple. With a few tips your team can avoid being the practice killing culprit. How many times have you seen team oil down the track at the first race or practice of the year? Unfortunately, major track oil downs seems to happen every year - at every track and at every division. Luckily, a British Petroleum Gulf Coast top kill operation isn’t needed. Simple construction tips and standard care get the job done. If nothing else maybe some conversation on the topic will save a few tracks from the dreaded oil downs.

Since most late models run quick change rear ends it is easy to find the proper fill level as site plugs guide the way. Rear end pumps and auxiliary coolers can complicate fill levels so it pays to fill the system with a predetermined amount of fluid. Knowing the exact amount to fill your rear end speeds gear changes at the track and eliminates the chance of over filling. The next time you drain your rear end simply measure the amount of fluid. With the results you can then pre-package the correct amount for a quick refill.

For rear ends, a tank with a reservoir is a great idea. Rear end heat is excessive and controling the fluid and heat is a real issue. Mounting the tank up high with a line that allows gravity to return fluid back to the rear end is recommended.

Your rear end breather system, while simple, needs a few tricks to keep your rear end fluid in the car. A baffled vent tank provides added insurance. A roll bar mounted or sheet metal mounted tank version will work on any late model. Mounting your rear end vent tank as high as possible is a good move. Gravity helps any fluid that runs up the line to drain back into the rear end.

Simple things like using a 3/8” minimum rear end vent line help as well – smaller vent lines are prone to clogging. Be sure that the vent hose runs in an S shape but avoids droops in the line where oil can collect thus blocking the air from traveling to the vent. Your vent hose must run continuously uphill from the rear end to the vent. Any hose sag could clog the vent system and you will end up with rear end pressure build up and leaks at every gasket.

You can use a standard vent on the rear end without the baffled reserve tank. Going this route saves a few ounces of weight and if everything in your rear end and in your filling process is done correctly a vent without a reserve tank will work fine. For me – the insurance of a baffled reserve tank on the rear end is a wise choice. The small cost and weight difference give you added insurance.

Rear end heat can be very intense as noted by the fine stench in your garage after a 100 lapper. The overall oil volume in your rear end is small and it does not take much overfilling to create leakage. The heat experienced in a rear end leads to high expansion rates so a baffled tank wins out compared to saving a few ounces with a vent that does not include a reservoir. Vents without reserve tanks work great for venting axle tubes and transmissions.

Engine venting is another easy to design system yet again we see cars oil down the track every year due to overfilling the dry sump tank or improper venting. With a dry sump system a sealed system at the engine seems best. Valve covers are unvented and the typical vents are replaced with a number 16AN line connecting the valve cover with a return back to the vented dry sump tank.

A dry sump breather tank should include internal baffles and plenty of vent area. Running your vent line with out sags wil prevent oil from collecting in the low spots in the line ensuring a free flow of air for proper venting. The sump tank shown includes a drain valve for easy maintenance.

Measuring your dry sump tank to the correct level is simple. A dip stick works fine but you do need to guard against any oil that is in the pan. With a dry sump the pan should have minimal oil but it is good practice to verify the pan is dry and verify that your sump tank level is in the safe zone..

A number 16 AN line from a valve cover back to the sump tank is a proven venting method. The venting is done at the dry sump tank and the engine is “sealed”. Your #16 return line needs to run downhill from the valve cover to the sump tank. At the sump tank, a line is run to your dry sump breather tank and again gravity needs to be considered. The line from the sump tank to the breather needs to run uphill in a sag free fashion.

Since transmissions generate little heat, in comparison to engines and rear ends, a simple vent can be used without a reservoir. The idea is to simply vent transmission pressure due to heat expansion. If you mount your vent as high as reasonable a simple tank less vent will do a great job of keeping fluid in your transmission. That said - taking the simple step of running your vent line without line sag is a great idea. A baffled tank is always a good idea but at the transmission the added insurance is not a requirement as compared to the engine and/or rear end.

A vent without a reservoir works fine on transmissions and axle tubes. Lower pressures and less heat generated in these areas allow the lightweight and inexpensive simple vents to function properly. As with all vents be sure the vent hose is free of line sags so that oil doesn't pool up and impede the venting process.

While you radiator cooling system is completely sealed, an expansion tank will help your car run cooler and ensure you are getting the most from your cooling system. Installation is simple. A ¼” NPT is recommended for an air line bleed. A ½” line is connects to your water pump. The 1/8” fitting allows for venting when your cap pressure is overcome and can be routed to a visible place such as the windshield to alert your driver to a heating problem. The reserve tank gives you the extra capacity as the car reaches the maximum safe water temperature. Routing the vent hose to the windshield gives the driver early warning allowing you the opportunity to identify and repair cooling system issues before they take you out of the race.

Roll bar or panel mounting of reserve tanks works on nearly any car cooling system. Remote vent tanks often include a billet cap filler neck for added security and durability.

A cooling system expansion tank can help you car run cooler. Note the billet filler neck for added cooling system reliability.

Venting your fluid systems properly will add to the longevity of your drive train and help you to avoid embarrassing oil downs.. The tale tell strip of leaking fluid follows you to your pit area for all to see and with simple common sense vent installation you can keep your fluids where they belong.

Go Forward – Move Ahead

Jeff Butcher
Courtesy of JOES Racing Products
8/01/10
http://www.joesracing.com/

Make or Brake

2010-08-16T15:27:00.000-07:00

When I was helping my Dad work on racecars, at the age of 12, he taught me that 4 tires work better than 3 for the best corner speed. The same thought applies to braking – 4 tires work better than 2. Ensuring that your brake system is set up properly will gain you speed throughout the race. Teams that spend the time and think out the variables will beat their competition by out working them and the cost is generally effort over big dollars. Getting the most from the rear brakes will make your car faster and easier to drive. With more braking power your car will be there at the end every time.

To get the most from your brake system you will want to get the rear brakes to do as much of the work as possible. Often teams and drivers run a disproportionate amount of front brake as pushing the window on rear brakes can make the car loose on corner entry. While too much rear brake can cause entry problems, there are some basic ideas that will allow you to run more rear brake. The goal is to take pressure off the front brakes. If your car constantly has front brake rotors that are glowing red then perhaps the cure is to get the rear brakes to do as much of the work as possible. Maximizing your rear brakes is a key ingredient for long lasting speed.

Feeding your brake system with cool air will help your components last and make your car faster at the same time. For this application a single hose gets the job done, but two hoses are often a good idea. The odds are stacked in your favor if you spend the time to saturate your brake components with plenty of cool fresh air.

A proper brake balance bar set is a simple place to start. Following the manufactures brake balance bar set up sheet will prevent many problems. Often I have seen brake balance bars that allow the rear master cylinder to engage before the front. When this occurs the car will be unstable on corner entry and regardless of how much front brake you dial in the car simply will not be fun to drive. Read the manufactures brake balance instructions thoroughly. You can check your car easily as the brake balance bar should be perpendicular to the frame when the brake pedal is depressed. If your balance bar is perpendicular to the frame at zero brake pressure then it is likely that the rear brakes will engage first. Whenever the rear brakes engage first you can bet handling problems that are impossible to overcome will follow.

Another common brake balance bar set up problem is proper clearance at the clevis. Refer to your manufactures instructions but in the end the master cylinder rods should be parallel and the components should have enough clearance to prevent binding throughout the brake balance adjustment range and through full pedal motion. Without proper clearance the brake balance adjuster can bind up during the race at full rear or full front bias making for a tough night.

Drivers play a role in maximizing rear braking as well. Brake smashers will require more front brake bias whereas smooth braking drivers can run more rear brake. By spacing out the time between lifting off the throttle, rolling in, and then applying smooth braking pressure provides the opportunity for teams to get more from their rear brakes. Smooth drivers that are easier on tires often get the most from their brakes.

Selecting the right friction material on your pads will help you with your goal of running more rear brake. Heavy brake users almost always end up with harder pads on the front whereas smooth drivers can use softer front pads. Finding the right combination for your car, driver and brake system can be a trial and error process. You can speed the process by working with your pad manufacturer or the parts supplier at your track. Typically, your parts supplier will know what competing teams are purchasing. Your team can tailor choices based on the appropriate variables and your crew usually knows if your driver relies on heavy brake pressure. If you build your system right you can win races with a heavy braker or with a smooth driver. If you have a brake smasher encourage using less brake pressure but remember that it is hard to change a driving style.

Rotor and caliper size comes into play – if you run lightweight components you will build brake temperature very quickly and can overstress undersized parts. Initial stopping force may seem fine but if you go through center on the heat range then the components become too hot and the heat is not dissipated properly due to the lack of mass. Warping and glazed pads are common results when under sizing brake components. When the heat induced brake fade occurs, the result is a natural adjustment of adding more front brake bias. For short tracks I would always choose the extra weight associated with a good brake system verses compromising braking efficiency and longevity. The weight savings offered by brake components that are too light is not worth the negative results.

Proper brake ducting is a must. For short tracks I would worry less about aerodynamics and drag and focus on keeping the brakes fed with plenty of fresh cool air.

Locating your brake ducts towards the center of the nose will feed your brakes with the most air. As you move towards the outside of the nose the air moves around the car and not through your brake ducts. Mounting the brake ducts as close to the radiator opening pulls in the most air.

Pulling air from the center of the nose as close to the radiator opening as possible improves airflow to your brake system. If you place your ducts too close to the edge of the nose air goes around the car instead of through your duct work. Keeping your brake system cool is a priority over the minimal negative aerodynamic effects. For short tracks good brakes prevail over any aero advantage.

In line fans are an efficient and inexpensive way to keep your brakes cool. For short tracks fans are a must. They are lightweight and with a flip of a switch they can be turned off if needed.

Rear brake ducting is not always needed but I think it is a good idea. Fresh air to both the front and rear brakes helps the components last longer and can prevent seal damage, fluid boiling and pad glazing. As we focus more on rear braking power then proper ducting comes into play.

Adjusting your car with a brake balance adjuster during the race can be your ticket to victory lane. When you have a tight car dialing in more rear brake can be an easy cure. A loose entry is often fixed with a few turns to the front. Selecting a brake balance adjuster that has an easy to reach handle helps drivers to make bias changes under race pressure. Adjusters with ball detents ensure that the bias adjustment stays put and the detents assist in monitoring the front to rear bias setting.

Using a brake balance adjuster system with an easy to reach handle and ball detents helps drivers to maintain the desired brake bias setting under race pressure. This model has heavy duty flexible connection hardware that eliminates binds at the balance bar. The lightweight construction bolts to your car fully assembled due to the mounting hole layout. Be sure to check your manufacturer's instructions for the proper brake balance installation.

Choosing high quality fluid in the smallest containers possible is another critical braking rule. As soon as a bottle of fluid is opened it begins to deteriorate. Moisture in the air reduces the boiling point nearly instantly so it is a good idea to use only new bottles when filling your system and toss out partial bottles right away. Once opened – brake fluid will never be as good as a fresh bottle.

Bedding brakes is an often overlooked area. Rotor bedding and pad bedding are to separate processes. Be sure to clean new rotors removing any oils or foreign materials. Rotors need to be brought up to operating temperature slowly and then returned naturally to ambient temperature.

When bedding rotors I recommend taping off most of the duct work and ask the driver to bring the brakes up to temp with several stops. A few stops at easy pressure and then several at medium pressure. Just simple brake stops without being overly aggressive. Upon returning to the pits I get the car on stands and rotate the wheels every few minutes to prevent the pads from sitting in the same rotor spot during the cooling period for even heat dissipation. Proper rotor bedding will provide for longer lasting rotors and reduces the chance of heat cracking. Once the rotors have cooled completely your driver is ready to use the brakes at their discretion.

For pad bedding follow the manufactures instructions but be aware it is a needed step. Bedding pads properly cures the pads and preps them for race conditions. Bedding improves stopping power and prevents pad failures. When bedding pads on used rotors, be sure to remove the existing pad material off of your used rotors. This is especially true when changing pad compounds. A vibrating or DA type sander with medium grit sand paper will work fine. Cleaning off the existing pad material from used rotors allows your new pad material to mate to the rotor for consistent performance.

With a few minutes of time you can improve lap times by helping your car to stop efficiently. Using all four tires to get your car deep into the turns is much better than using just the front 2. By spending the time to set up your brake system correctly, you can use effort verses money to gain long lasting speed. Stop and take the time to use the braking action to help your car go.

Go Forward – Move Ahead
Jeff Butcher
Courtesy of JOES Racing Products
07/1/10
http://www.joesracing.com/

Caster Creativity

2010-07-19T14:27:00.000-07:00

Why do we need a caster? The most direct answer is for directional stability. Without caster our racecars would wander, in an unstable fashion, on the straights and be hard to handle at high speed corner entry. Positive Caster allows the front wheels to trail behind the caster line for true tracking. Extending a line from the top ball joint though the bottom ball joint creates the caster line or caster angle. If the line extends forward of the lower ball joint and contact patch you have positive caster – behind is negative caster and both are measured in degrees. Positive caster allows the wheel to trail behind the line for stability. The most common and easy to understand example is a shopping cart wheel. As soon as you move your shopping cart forward - the front wheels spin and trail behind the positive caster angle.

Caster is measured in degrees. When a line is extended from the top ball joint through the bottom ball joint the caster line is created. Zero caste would be when the upper and lower ball joints create a line that is perfectly vertical. Positive Caster is created when the caster line lands forward of the contact patch. Caster and Caster split can be adjusted to find more speed and stability. A common example of caster is a shopping cart. As the shopping cart is pushed forward the front wheels spin back and trail behind the caster line.

Caster creates stability as the geometry created forces the wheels back to straight. The front wheels are “encouraged” to stay straight as turning them involves lifting the car weight. Expensive street cars often have high amounts of positive caster providing them with a superior and stable feel. The drawback comes in the form of added steering effort. The invention of power steering has allowed for more caster to be added. When power steering fails it is easy to see the negative effects. As soon as the dripping wet driver gets out of the car and asks for help opening a beer due to his arms being worn out it becomes clear how power steering has allowed higher amounts of caster.

In stock cars, we can use caster to help our cars going beyond simple directional stability. Caster split is often used as a chassis adjustment. Running more positive caster on the right than on the left is common. The question is how much split and how much positive caster should you run?

Caster split and the appropriate amount chosen is one of those chassis adjustments where there is not a magic amount or a right or wrong answer. If you understand the effects of caster split you can make your own decisions based on your track, driver and goals. Commonly crew chiefs run 3 degrees positive on the right side and 1 degree positive on the left side. At times it may pay to run 4 or 5 degrees on the right and .5 degrees positive on the left. It all depends on what you are hoping to accomplish for your specific chassis needs.

An often overlooked element relating to stock car caster is that the more positive caster you run the more “beneficial” camber gain you will get. As the car rolls you will see more negative camber gain on the right side and more positive camber gain on the left in lock step with running additional caster. Camber gain through travel is typically a good thing but like all adjustments you want to avoid going too far. If you are aggressive with A-Arm lengths that create high amounts of camber gain you want to be careful that you do not get to aggressive with caster. As always balance applies.

You can find a "speed secret" by understanding that more caster beneficially adds to negative camber gain on the right front and more positive camber gain on the left front. You can check this effect by measuring your camber gain at your current setting and recording the numbers. Next - add caster and check your camber gain again and you will see the benefits visually right in the shop. With the knowledge you can tailor your set up package to overcome obstacles presented by your car, track and driver.

To visualize the benefit of the caster induced camber gain it pays to think in extremes. If you are running 3 degrees of positive caster on the right this would be in the normal range. For our visualization, picture adding caster until the caster line is adjusted an exaggerated amount until it becomes completely horizontal. At this hypothetical and exaggerated point, the result would be pure camber change instead of directional change. The benefit is that with more static caster, the right front wheel would gain more negative camber as steering input is increased. The left front wheel gains more positive camber as the wheel is turned. Cool, we get more camber gain when we need it most by running more caster through a left hand turn! Even experienced crew chiefs can be unaware of the relation to caster and beneficial camber gain in left hand turns. Personally, I find understanding the camber gain from caster to be a true “speed secret”.

Running more caster on the right side verses the left is an adjustment tool that can help cars turn left. The amount of caster split can create benefits as the wheels are turned. More split will “de-wedge” the car at maximum steering input helping the car to turn in the middle. As the steering wheel is un-wound - wedge is added back helping the car to hook up better on exit. Wedge is added back as the wheels return to straight or even back through to the right. You can easily see this change when you have the car on scales. The next time you weigh your car and you have recorded your race ready numbers simply turn the steering wheel 10 degrees left and you will see your scale numbers display less wedge when the wheels are turned left.

You can use turn plates to help measure caster. Using a quality caster camber gauge the turn plates allow you to turn the wheels exactly 20 degrees for precise caster measurements. You can also use the turn plates to visually see the caster induced camber gain when running higher amounts of caster. Simply check the camber gain with the wheels straight and compare the camber gain numbers to your results with the wheels turned 10 degrees left.

Based on the prior paragraphs it would make sense to run high amounts of caster and plenty of caster split yet understanding the concept will create speed whereas just throwing in aggressive settings could set introduce problems – it pays to understand your changes in advance. Too much of a good thing leads to trouble. There are many variables to consider when it comes to caster amount and split. You must consider other geometry choices such as A-Arm length to avoid ending up with too much camber gain. Too much split can make the car pull too hard to the left making the car tough to control in traffic and on corner entry.

You can thank power steering for creating options with high amounts of caster. Power steering overcomes the steering effort and in the past high amounts of caster was simply not possible as the effort required wore out the driver in a handful of laps. Prior to power steering it was quite common to run negative caster on the left front to reduce steering effort.

For less experienced drivers, I recommend running as much caster split as you can get away with. Something in the neighborhood of 4 positive on the right and 1 positive on the left will help your rookie driver. The idea is that the split will help them to catch the car when it gets loose preventing them from spinning out. As the rookie drive unwinds the wheel wedge is automatically added back in giving the rookie a little help anticipating the loose car before they go for a ride. The split gets wedge back in the car quickly as they correct back to the right giving them security and a helping hand. For rookies, I might compromise my faster caster set up to ensure they finish races. Giving rookies caster split builds their confidence and helps to prevent them from getting behind on the steering.

On most stock cars the top A-Plate is set back to build in the positive caster that most people run. Using slotted A-Arms and slugs makes for quick and consistent adjustments at the track or in the shop.

For experienced drivers, that have a good feel, I might reduce the caster split. The chassis premise is that you know your good driver and you can allow him or her to drive the car without interference from overdone geometry. Again, there is much to consider and other chassis goals would easily override this choice. The experienced driver feels the car and sometimes wants the control in their hands as they anticipate with confidence. In this case, they want to turn the wheel for the desired effect verses being forced into a geometry change that happens outside of their steering input control.

I would push the window on caster amounts and splits on tracks that are smooth and with sweeping corners. If the driver can consistently turn in and unwind the wheel smoothly then adding caster and split can help find speed due to the geometric benefits discussed.

All that said – caster and caster split is very much car, track and driver specific. In much of the country our short tracks are worn out, bumpy and the corner transitions can be abrupt. For rough tracks where drivers are constantly sawing on the wheel, too much caster and caster split can cause the car to be erratic. All the directional change from a steering wheel that is being turned back and forth quickly will upset the car. You can imagine that turning the wheel quickly back and forth would inconsistently put wedge in then out, back and forth steering input would add camber gain then abruptly take it out.

At rough tracks or if your driver nervously saws on the wheel – you will definitely create too much of a good thing resulting in a car that never knows quite what to do and stability is lost. Many of the races my cars won were on rough tracks and I commonly ran 2 degrees positive on the right and .5 degrees positive on the left. The idea was to keep the consistency in the car over the bumps and through quick back and forth steering input. I truly believe this to be one of my speeds secrets at rough tracks. Maybe my competition was being aggressive with their front end settings causing their cars to fade later in the race on the worn out surfaces. That is why they throw the green and checkered flag as there is not a right and wrong here but simply a competitive choice.

Your team can analyze your track, car and driver to see if the benefits of added caster and caster split would overcome obstacles that you face. Used properly there is plenty of speed to be found in the correct caster settings. Your job is to understand the changes through chassis roll. Through understanding you can use caster to create speed and your additional “planned” choices will give you an edge over your competition.

Go Forward – Move Ahead

Jeff Butcher
Courtesy of JOES Racing Products
6/01/10
http://www.joesracing.com/

Ackerman

2010-06-11T11:07:00.000-07:00

Rudolph Ackerman invented Ackerman Steering back in the days of horse drawn carriages. Monty Ackerman is my neighbor and an excellent basketball coach of 10 year old kids. While we can give Rudolph credit for the Ackerman Steering theory, Monty can help us to illustrate how the theory is applied.

When my kids were 10ish - my neighbor Monty was kind enough to volunteer to coach basketball. Monty had figured out the right way to teach kids and was a perfect role model for the little ones. He set a fine example for us bigger kids too. As a parent, I wanted my kids to work hard in hopes that they would become the next Michael Jordon. It seems in my enthusiasm, I would take youth basketball too seriously and applied my cheers in a less than perfect manner. I still remember today the glare from Monty when I vocally displayed displeasure with the teenage referees. Oh, Monty is a mild mannered man and while very rare, I know I had his glare coming. It is funny to look back and vividly see how too much of a good thing was a detriment. It is a bit embarrassing to me now but my support for my kids clearly went over the line. I wonder how many other parents go a little too far at the quarter midget track.

My goal in the basketball gym was to be supportive of my kids but, in implementation, I went way too far. Live and learn - sorry Monty! While Monty has nothing to do with the Ackerman Steering theory, he has everything to do with doing things in a balanced manner. His wonderful family exemplifies balance. When using Rudolf Ackerman’s principal, it pays to understand that everything has a time and place and using the “right” amount of steering encouragement will help your car go faster. Knowing when to use the Ackerman principle is even better.

Typical stock cars have a slotted adjustment on the Left Front for Ackerman Adjustment. The fixed bolt on the right shown here is planned out by your car builder in conjunction with the rack forward and aft mounting location. With the slotted LF adjustment moved back the tie rod end moves closer to the ball join center line the steering geometry speeds up how rar the left front spindle turns. Adjusting is simple yet chassis engineers should utilize "just enough".

Ackerman Steering as applied to stock cars is simply using geometry to make the LF tire turn farther and faster than the RF tire as the car is turned to the left which is known as Pro-Ackerman. The simple idea is that since the radius at the inside of the track is shorter than the outside it follows that the LF will follow a sharper radius than the RF. The sharper inside radius can create the need for more degrees of steering at the LF - that is the idea anyway. If you imagine a car with the steering wheel locked fully to the left it would drive in a perfect circle under power. The circle created by the LF would be smaller than that of the RF. Thus, more degrees of LF steering can make sense. The idea is similar to how rear stagger uses the LR tire and a smaller LR diameter to match the smaller arc found on the inside radius of the track.

You can think of stagger, rear steer and Ackerman in the same chassis category If you match up the Ackerman Steering theory and rear steer you could overcome handling characteristics at a given track. But - excessive stagger, Pro Ackerman and rear steer could be a recipe for disaster so moderation applies.

Anti-Ackerman can sometimes be used to your advantage as well. With Anti-Ackerman the LF turns less than the RF through a left hand turn. At times, we can use this geometry to make our cars faster.

The question is when does more LF steering (Pro-Ackerman) make sense? My answer is on smaller low speed track. If your track has a sharp steering transition in the center you might find a speed gain by using Pro-Ackerman. If your track is large with smooth sweeping corners then Pro-Ackerman will produce more negatives than it is worth. Remember our pal Monty – we want to avoid too much of a good thing. With Ackerman it is our goal to not go overboard. Under using Ackerman is better than using too much nearly every time. I wish I could go back in history and use a little less “enthusiasm” at the gym.

Pro Ackerman is shown in the drawing as the LF tire turns more than the RF. The idea is to match the LF arc to the smaller radius found at the inside of the track. Be sure to keep in mind the geometry changes as the car turns left while remembering to consider the steering changes as the wheel unwinds back to the right. Ackerman should be used in moderation but it can be the chassis seasoning tha makes your set up "just right".

On a stock car Ackerman is adjusted by using the slot on the LF spindle. With a rack and pinion steering system the tie rods run slightly forward from the rack out to the mounting point on the spindles. As you move the tie rod mounting point closer to the ball joints at the LF you speed up how fast the LF turns and you increase how much it turns. The concept is the same with a drag link and steering box.

A standard Pro-Ackerman amount is 2 degrees in 10 degrees of steering. In other words, if you turn the RF 10 degrees the LF would move 12 degrees. It pays to think about how the LF turns when using Pro-Ackerman. As you turn left, the LF turns more than the RF. As all things have an equal and opposite reaction you should understand that the LF turns back faster at corner exit as well. You can use the Ackerman effect to your advantage in the middle while turning left and on exit as you unwind the steering wheel.

In the northwest there are two tracks of similar quarter mile size yet, my thoughts on applying Ackerman are completely different. Wenatchee Valley Speedway was rebuilt by racing legend Garrett Evans. Garret is a racer and he rebuilt Wenatchee into a personal shrine to include new pavement and high banked sweeping turns. The playground for the kids and awesome viewing areas are added bonuses. The other track for comparison is South Sound Speedway which was revamped by the Behn Family. Butch Behn is an old school promoter and took a worn out old speedway and made it very cool. The million dollar stainless steel self cleaning toilets purchased from the city of Seattle for a few hundred bucks are a comical yet clean example of Butch’s wisdom. Both Wenatchee and South Sound are unique tracks. Similar size - but, completely different. These two tracks make good examples for describing when and how to utilize just enough Ackerman Steering geometry.

At Wenatchee, I was not a fan of Pro-Ackerman. In fact, I would prefer Anti-Ackerman when racing at the Wenatchee quarter mile. Wenatchee has a smooth entry into the corners and the car rolls through the middle if you have the car right. But, even with a fast car, the dynamics of turn 4 at Wenatchee could create a loose condition on exit. Pro-Ackerman would exemplify the problem. On exit and under power the rear tires would effectively push against the toe out created by Pro-Ackerman on exit. The scrub of front tires resists the power of the rear wheels causing the car to break loose late in the Wenatchee corners. At Wenatchee – if you could turn the car in the middle and get a straight shot off the car would hook up and be really fast. Pro-Ackerman could and does make the car loose at late exit as the LF front tire is turned too much under hard acceleration. For this reason Anti-Ackerman is a better plan at this particular track. Anti-Ackerman would slightly toe in the LF on exit. The small amount of Anti-Ackerman induced toe in would help the driver to unwind the steering wheel at late exit point. The right place at the right time applies here and the Anti-Ackerman affect would help the driver be smooth and hooked up on exit.

South Sound presented unique challenges and I would look at Ackerman in a different way. It is interesting to think about how tracks that look similar from the grandstands invoke a chassis set up mindset that is completely different. The South Sound challenge is that the driver needs to turn the wheel aggressively and quickly in the center. At Wenatchee you can drive through the center with a comfortable amount of steering input. At South Sound, drivers have to get after turning the wheel in the middle. The corners are not quite as rounded and the transitions are more abrupt. The groove relies on a big time pivot in the middle. I think the chassis challenges are that at Wenatchee hooking the car up at late exit was my goal.

At South Sound a strong pivot in the middle was comparatively more important. If the car pivoted in the middle it would take a nice set and be hooked up on exit. All tracks need a good pivot in the middle but at Wenatchee a good pivot can lead to late exit looseness. At South Sound a good pivot makes for a longer straight away and more over all speed.

The result is that Pro-Ackerman can help in the middle but might come at the expense of the exit. The trick is to use the Ackerman theory without creating the drawback or condition inherent in a given track. At the end of the day – zero Ackerman is better than too much. That said – the right amount can help cure a corner condition if the amount and timing are right. Ackerman has no affect on the straights and the geometry change increases with steering input. This idea can help you to have a stable entry as Ackerman change increases the more you turn the wheel. At entry the affect is minimal.

Depending on the track you can add extra Pro-Ackerman for qualifying. The thought is that you may be able to add “too much” Pro-Ackerman for 2 laps. The added LF toe out can build heat quickly in the LF for a qualifying run. Trial and error apply here but you could make the car loose on exit if you get to aggressive. If LF temperature is a problem at your track or if you run a high amount of wedge then a quick addition of Pro-Ackerman for qualifying can sometimes find you more speed.

Turn plates can be used to measure your Ackerman. Turn the RF tire 10 degrees and note how many degrees you have on the Left Front. IF the Left Front ends up with more than 10 degrees you have Pro-Ackerman. If the LF ends up with less than 10 degrees you have Anti-Ackerman.

Ackerman can be classified in your mental adjustment section with rear steer and stagger. The concept is that you are matching up the roll out of the left and right side tires by using one of these three adjustments. If you combine rear steer, stagger and Ackerman you can build a chassis package that line up the best benefits of each. You should guard against using too much of any one of these adjustment types and if you are being aggressive with all three you could be asking for trouble late in a run. If you time the dynamic movements of Ackerman and rear steer could find you a rocket ship set up. Go too far and your rocket will become an evil boat anchor.

Stagger is felt all the way around the track as the tire size is the same on the straight and in the turns. Rear steer occurs as the car rolls and Ackerman changes as depending on the degrees of steering input. You can imagine matching up the geometric change created by rear steer and Ackerman. Again – these options are best on shorter low speed tracks but they do have their place anywhere.

Thought about the Ackerman affect is usually confined to when the car turns left. In practice, it is equally if not more important to think out what happens to the car as the steering wheel unwinds. Often, Pro-Ackerman is used has a crutch to help the car turn through the center. Many times racers would be better off if they used other adjustments to help the car turn through the center coupled with using Anti-Ackerman to help keep the car hooked up on exit. I will take a car that is a touch snug in the center with a solid exit every time.

To achieve the most speed I think of stagger, rear steer and Ackerman as chassis seasoning. Just like a touch of salt on a good steak you can make your car feel better by adding a touch of seasoning to an already fabulous steak. Add too much salt and you are bound to upset the meal. While Rudolf invented Ackerman – we can learn from Monty and apply the benefits of Ackerman in a calculated, moderated and balanced fashion.

Go Forward – Move Ahead

Jeff Butcher

Courtesy of JOES Racing Products

4/28/10
http://www.joesracing.com/

Set Up Routine

2010-05-19T15:05:00.000-07:00

Pointing all four wheels the same direction is the way to find consistency and speed. Often I am asked what will happen if the rear end is out of square or if the bump steer is out of whack. The answer is, “I have zero idea”. When adjustments in your car are not right - there is no way to predict what will happen. I imagine the car will be erratic and it is likely it will feel different every time you get close to a corner. When you get to the track your car should be prepared. Completing every adjustment to your specs gives you the confidence to change wedge, stagger, shocks and springs without worrying if the car is loose because the rear end is crooked. Having the car set up with your numbers recorded is a needed part of your team’s efforts to build more speed each week and over the course of the season.

After a dominating performance in Phoenix, regarded engine guru Jim McFarland asked me, “So Jeff – your team just won the race. Do you really know how you did it?” Jim asked me this at the point in my career where I was starting to see success and was eager to learn. His simple question had a profound effect on me and I continue to learn from the question in the racing arena, in business and life in general. What Jim meant was that while it is great to celebrate a win, “do you know how you won and could you repeat the steps necessary to do it again?”

Jim taught me that having a plan that is sustainable is the way to increase the learning curve and was the key to ongoing success. Jim’s message was to enjoy success in the short term while understanding the adjustments and set ups allowing you to win again. We have all seen a one hit wonder and it is likely that those teams didn’t take the time to answer Jim’s question. Understanding your choices creates long term successes whereas winning by accident is like putting a monkey at a type writer until he spells a word. Keep the monkey off your back by understanding your chassis decisions. The concept is simple – plan to win. Plan to win in a repeatable fashion.

A set up plan will help you to build a race winning effort. In order to perform the set up routine the car needs to be completely ready to race. Full of fuel, everything done, full of oil, lead bolted down. Basically – after you finish the set up routine, the car goes in the hauler. When you reach the track it is ready to roll out of the hauler and onto the track. All fabrication projects are done and all projects are finished. Race ready means just that – ready to race.

I make sure everything is wrench tight before I take any measurements. At times crews measure with jamb nuts or bolts loose to speed the measuring process. When bolts/jamb nuts are tightened they can move rendering your measurements useless. It takes only seconds to loosen bolts/nuts and all measurements need to be taken with your components wrench tight.

Here is how I go about setting up an Asphalt Late Model in the order that I feel is best. I perform the set up process the same way each time and the car doesn’t leave the shop until my numbers are exactly right and written down. You may have another type of car but the concepts likely to be similar if compensate for your specific kind of racing.

Ride Height

I set the car on stands and use set up blocks to get the car up in the air with the wheels held at my ride height position. I do this on a level spot and mark the 4 tire locations on the floor so I can be sure the process is the same. If my floor is out of level I have already spent the time to shim the floor so everything is spot on. I spend the time to get the heights exactly right. Make sure to start with the race air pressure you plan to run along with your desired stagger.

Set the Front End

I set the lower control arms perpendicular to the frame and make sure there is a straight line that runs from the outer lower ball joints through the inner pivots. I then set the caster at the top as it seems most late models have the a-plates moved back to allow for adjusting on caster at the A-arm.

With the caster/camber, track width and toe set you can start the bump steer process. It is best to let the driver turn the wheel verses having them turn themselves over the bumps so I recommend running .002 out on the RF and .005 out on the LF. Setting the bump is time consuming but it pays back in consistent performance.

I then set my camber and adjust the toe with the car up on set up stands. From experience I would set the toe 1/16th in while on set up blocks because when weight was applied it seemed to come out about right. With the toe set, I would get going on the bump steer. I re-check the toe after I put the weight on the car and if I move the toe I re-check the bump steer. When weight is applied I get close to my 1/32 of toe out. Personally, I run .002 out on the right and .005 out on the left which is not much so I spend the time to get it right. It is okay if you use different numbers but because I chose to run a very small amount I made sure it was right and kept working until I hit those numbers exactly. Many car builders/chassis guys recommend more bump out and the amount you run is fine as long as it is repeatable and you understand what happens to the car under varying conditions. For me, I like the driver to turn the wheel and I see zero benefit of the tires turning themselves over the bumps. Most of our short tracks are rough thus my “choice” to run nearly zero bump steer.

Setting the caster and camber before stringing the right side allows you to line up the RF and RR Contact patches while taking your camber setting into consideration. A billet caster camber gauge has the machined precision needed for repeatable and accurate measuring.

Using a digital gauge for bump steer gives you accurate readings with out the need for doing math or watching 2 needles wind around wildly. This gauge has a reverse display for easy viewing and the billet tool is superior to sheet metal and tubing.

Square the rear end

My goal in squaring the rear end is to make sure that it is parallel to the rack and the inner pivot points of the lower A-Arms. I choose to run the lower control arms perpendicular to the chassis and make my caster adjustments on the top. In the end, the rear end needs to be square to the chassis and common sense prevails. I do square to the inner pivots at the front to eliminate the bends found in the mild steel that your car has been made from. Of course we start with a rear end housing that is straight.

First I clamp a perfectly straight edge to the bottom of the car 90 degrees to the straightest frame rail at the midpoint in the wheelbase. I verify that my inner pivots are parallel to the rack. On occasion I have to space the inner pivots a bit to account for frames that have bows in the mild steel. In the end, the Inner Pivots are parallel to the rack and the rack is exactly perpendicular to the frame. The Inner Pivots must be parallel to the rack or setting the bump steer will become a compromise.

Toe plates make quick work of setting your toe. With today's precision components I recommend running less toe out as compared to the past. If you have a rack and quality rod ends I would run 1/32nd or toe out to 1/16th of toe out. 1/8" or 3/16ths was the standard before but with better components we can run less and reduce rolling resistance for more speed.

I spend a ton of time getting my straight edge parallel to the Inner Pivot Line. Once I know my reference

straight edge is parallel I make sure it is 90 degrees to the frame allowing for the frame bows that are common. The frame rails are for reference and on average are square but I square to the front Inner Pivots and the straight line I created from that extends through the inner pivots through the outer lower ball joints. By squaring to the inner pivot reference line I am removing the variable of bows in the frame rails. With my straight edge perfectly located, I make peen marks in the bottom of the frame so I can set up my straight edge quickly next time. The marks come in handy when you need to check things at that track as I always carry the straight edge with me. While I maintain square to the frame I go the extra mile to and use the front inner pivot reference line.

I set my trailing arm lengths and adjust my trailing arm and top link angles. I set the J-bar heights and lock everything down. I line up the right side and ensure that my trailing arm and top link angles are correct. Most car builders line up the right side but you need to verify as if they want the RR set in ½” or something then you need to set the housing there to make sure your trailing arm angles line up with the brackets as intended by your car builder.

Line up the right side

Now that I have the straight edge to rely on I can quickly hook my tape and for fast 1 man measurements. I then set up a string on the right side of the car and line up the right side tires. I set the string at my frame height – some people do this different but frame height is something I can repeat the process and the method gets the contact patches in line. I set the RF straight and move the housing until all the string touches all 4 sidewall points on the right side. This method takes into account the camber setting you choose to run in the RF.

With the right side lined up I hang plumb bobs behind the housing as far out near the hubs as possible. A nut on the end of a string will work fine to hold the string tight. I hook my tape on the straight edge making sure the tape is running 90 degrees to the straight edge and take a measurement at each hanging string. I adjust as needed and check again. I repeat until I have it right on. Some people stop when they get within 1/32nd. I keep going until it is right on! Once I have everything tight and the rear end is square to my reference straight edge I recheck my right side string. If the right side no longer lines up then I move the housing until it does and start the rear end squaring again. Sometimes you have to go from the right side string to the rear end squaring multiple times. I only stop when the right side is lined up and the housing is exactly right.

Once complete I take an adjustable carpenters square and measure from the under slung frame rail to the RR brake rotor and record the number in my set up book. As long as the car isn’t bent I can get the left to right location with a quick measurement. By using the adjustable carpenters square, I have a nice quick check method to keep the housing located properly when track changes get fast and furious. The brake rotor is a straight and reliable reference point so the results are repeatable.

Moving on I get the lead in the car and set up my shocks and springs. Of course the car is already full of fuel and fluids. Once the car is at the minimum legal weight I move the lead until I have reached the allowable left side and my desired rear weight. For late models I set the lead and all weights with the driver in the car.

I set the stagger and adjust the wedge making sure the ride heights match what was used on my set up blocks. Every possible adjustment is recorded on my set up sheet and when I reach the track all changes are noted. At the end of each event I review my changes and record my thoughts about their success. I highlight adjustments where I felt I learned something new or if I overcame a particular problem successfully. I track my less than perfect decisions too as it is another opportunity to learn. I place my review comments in the same place in my set up book as over time I can review the notes and my knowledge base continually changes based on race experience.

Review

Set the ride height on set up stands

Set front inner pivot line straight through the lower ball joints

Set the caster at the top

Set the camber

Set the toe

Set the bump steer

Set the trailing arm and top link angles

Set the j-bar heights

Line up the right side – recheck the trailing arm angles

Square the housing to the inner pivot line

Load and adjust the lead – left side and rear weight

Install the springs and shocks

Set the stagger and air pressure

Set the ride heights

Set the wedge

Double check the front toe and adjust bump steer if needed.

Set the sway bar

Download your Free Chassis Set Up Sheets and Car Prep Sheets at the JOES Knowledge Center

Remember to understand and record your changes. When you win you will know how you got there and will find your way to victory lane again. Answer Jim’s question along the way and the monkey’s will stay clear of your back and jump on the backs of those that make accidental choices. A plan to win prevails and is a “choice” that is yours to make.

Go Forward – Move Ahead

Jeff Butcher

Courtesy of JOES Racing Products

3/23/10
http://www.joesracing.com/

Under Pressure

2010-03-18T14:14:00.000-07:00

Emotional pressure to find speed will be reduced if you manage your tire pressure with a plan. Every set up out there relies on the contact patch and getting the desired pressure at the point the rubber meets the road. Several important factors need to be considered for optimal tire pressure.

To achieve precise tire pressure readings you must have an accurate tire pressure gauge. Starting with the right gauge is paramount. Nearly all gauges are more accurate in the center of the range. For example; a 30 PSI gauge is going to be most accurate between 10 and 20 PSI. It will still work at 5 or 25 PSI but the percentage of error increases. For a 60 pound gauge you will get good results between 20 and 40 PSI. Just as before it will work fine at 15 or 45 PSI but the accuracy percentage goes down.

Racing Tire Gauges with a Glow in The Dark dial face are a big advantage when it gets dark. There is a difference in glow coatings and better quality gauges have coatings that glow longer. You can recharge a Glow in The Dark Gauge quickly by placing it near any light source.

Since accuracy is best in the center of the range, you should choose a gauge that fits the pressure ranges for your type of racing. Gauges found for $10.00 dollars at the local auto parts store are designed for passenger cars and their percentage of error is too high for racing purposes. If your passenger car has 30 PSI instead of 32 PSI it is really not too big of a deal but on a racecar 2 pounds would be the difference between winning and kissing your sister. Choose a quality gauge that has less than a 2% accuracy tolerance. Obviously, better accuracy allows your team to slice information for repeatable performance.

Larger tire pressure gauges such as this 4" gauge offer more accuracy. Larger gears allow for precision machining and the larger dial creates more resolution and better viewing angle. Rubber bumpers should always be included with racing tire gauges.

Digital Gauges
A quality digital gauge can give you better resolution yet you can be fooled by the digital display on a low quality version. Low quality digital gauges may post a number on the display but the accuracy must be supported by quality sensors for the display reading to be reliable. Digital gauges should have a backlight for easy night time viewing and the numbers should be large and easy to read. Digital, by itself, does not guarantee that the gauge will be more accurate. You may find a practical improvement as digital gauges remove the variable of viewing angle. Analog gauges can add to accuracy percentage error due to the viewing angle - the individual user’s interpretation of the needle verses the printed hash mark can cause a variation in results. A quality analog gauge will have minimal viewing angle error.

Digital Gauges can provide more accuracy but digital alone isn't the only factor. Quality racing gauges like the one shown is very accurate. Gauges with sensors designed for passenger car use are inexpensive but their low quality sensors are less than the standard required for racing.

Paying more for one digital gauge verses another does not guarantee accuracy but it can be a factor. There can be an accuracy correlation to gauge head size. If the display is very small then that could be a clue that the electronics contain low cost sensors. Digital sensors intended for passenger car use simply do not provide the resolution needed for racing. If a digital gauge rounds to half pound or even full pound you most likely find improved accuracy and quality with a gauge that reads in 1/4 pound or better digital increments.

Analog Gauges
For analog tire pressure gauges you will find many options. Gauge faces that have Glow in The Dark coatings are a big help when it gets dark. There is a difference in coating quality so take note of the manufactures that utilize longer lasting Glow coatings.

Analog gauge head size is a factor in assessing quality. In general, a 4” gauge will be more accurate than a 2” gauge. Larger mechanisms typically have more precision as the larger gears have the mass for easier machining. The longer throw on a 4” pressure mechanism offers smooth and steady needle movement resulting in improved accuracy as compared to a 2” version. With a larger gauge face the needle is easier to read and interpretation error is reduced as the larger circumference provides an expanded scale and improved visual perception of the enhanced scale graduations.

Liquid Filled Analog Gauges
There is a myth that liquid filled gauges are better. The mere presence of liquid does not ensure better quality. Liquid filled gauges may or not be good quality but the liquid alone is not the factor that guarantees accuracy. Liquid filled gauges work great to reduce needle vibration. If a gauge were to be mounted on a machine that vibrates then the liquid would help to reduce needle shake or bounce. Since tire pressure gauges are not used in a setting where vibration is an issue, the liquid serves only as a gauge damper. The liquid does absorb shock as the needle movement is controlled during gauge inflation. This dampening effect is desirable. Quality analog gauges have internal dampening systems without using liquid. Liquid is one way to provide dampening but dampening methods that do not utilize liquid are equally if not more effective.

Tire Gauge Care
Regardless of the type of gauge you use, it pays to take proper care of your precision tool. All racing gauges, whether digital or analog, should have a rubber bumper for protection. Ideally, you would never drop a tire gauge. Dropping tire gauges even one time can cause accuracy error potentially voiding the manufactures warranty. If you drop a tire gauge and that does not a rubber bumper then the shock is transmitted directly through the analog mechanism or digital sensor. Permanent damage can be the result. Rubber bumpers on tire gauges of any type are a must.

Using tire gauges properly is as important as selecting the right gauge. Over pressuring the gauge can and will damage your gauge. Let’s say a racer purchased a 30 PSI gauge to be in the center of the range for racing tires. On the way to the track the racer’s trailer gets a flat and our racer uses their racing gauge to check the trailer tires. The subsequent 60 PSI pegs the needle. In an instant it is more than likely that permanent damage has occurred to the racing gauge and the over inflation has destroyed the calibration. Care must be taken to not over load analog or digital gauges even one time. Tire gauges are precision instruments. Racing tire pressure gauges lead a hard life and the rough treatment introduces a decline in accuracy. Storing gauges safely during transport and on race night will provide for better long term performance.

Calibration
Many gauges have a fixed calibration and can not be calibrated in the field. Fixed calibration is held nicely for long periods of time if gauges are not dropped and are used within the required range.

If you have a gauge that can be calibrated you need to take it to a certified testing house or send it back to the factory for periodic calibration. Neither of these options is ideal. For racing purposes the most practical method is to simply purchase a second gauge and store it for the sole purpose of checking the calibration of your main gauge. Upon purchase – compare the two new gauges on and verify that they obtain the same reading on the same tire. If there happens to be a small difference simply record the difference and periodically verify that the gauge you use matches your master gauge and the original comparison. Use the master calibration gauge only for testing. Keeping a test gauge as a master is the most practical way to verify the accuracy of the gauge you rely on. You can compare your master gauge against you track gauge weekly as part of your set up routine.

If you use two gauges on one tire and both gauges give you the same result it is likely that they are accurate. While possible, t is unlikely that two gauges would be off by the same amount.

Adjustment
You can use tire pressure and your accurate pressure readings to adjust your car. For Bias Ply tires the air pressure can be adjusted to help your car get through the turns. Thinking out the adjustment options can help you maximize practice time or provide handling adjustability during pit stop races.

Using an accurate tire gauge will help you match your contact patch for adjustability. Thinking about how air pressure affects contact patch size, stagger and sway bar load will give you more options to find the fastest set up.

It has been my experience that you can not stretch bias ply tires so it is important to buy tires that are the right size to begin with. Crews sometimes over inflate tires in an attempt stretch them. Measurements taken right after a tire is over inflated can show a larger circumference. The reality is that as soon as the tire gets hot the tire tends to return to the factory size. Consistency in your pressures at each corner on the car is critical too. Adding 5 pounds above your standard pressure to the RR in an effort to meet your stagger numbers is not recommended.

Purging your tires and using nitrogen can eliminate a "bad set" of tires. By reducing the moisture content in the tire through purging air is replaced my nitrogen. Moisture causes your tires to grow inconsistantly. Keeping the humidity in the tires consistant will help your tires to maintain their size. Filling the tire with nitrogen and draining it 3 times gets most of the moisture out. After 3 purges, the gain is minimal. A purge tool will allow you to preset the bleeder so you can clip it on and not worry about atmospheric air re-entering the tire after you have spent time on multiple nitrogen purges.

With Bias Ply tires I recommend staying within 2lbs of your standard per tire to dial in stagger. If you can’t get to your desired stagger within a 2 PSI window then your pressure and spring rate changes will be so dramatic that having the right stagger will not overcome the pressure induced spring rate changes. Over inflated tires create too much heat and premature wear. Check your tire sizes after mounting them and if they are not the right size then ask your supplier for another set. I am more likely to drop the left side tire pressures to help with stagger adjustments verses over inflating the right – it is a balance but over inflated tires do heat up in the center. Over inflation can cause over heating and stagger variations so it should be avoided.

To help your car handle here are some Bias Ply pressure tips

Car is loose everywhere:
Add Pressure to the RF which loads the sway bar for more cross weight.
Drop Pressure to the RR which reduces stagger, adds cross weight, and makes the RR footprint larger for more grip.

Car is loose off:
Reduce pressure at the RR which makes the RR footprint larger for more grip, adds cross weight, and reduces stagger.

Car is tight in the Center and Loose off:Drop the LR tire pressure. Drop the LF Pressure. The added rear stagger will help the car turn in the center. The larger LR footprint will help on exit. With both left side pressures being lowered the cross weight change will be minimal. The larger LF footprint will create more grip in the center helping the car to turn. Cars that turn better in the center have a better angle for the exit so often curing the center automatically improves exit issues.

Air pressure on bias ply tires is fine tuning tool and the adjustments work best when the car is already handling well. Fine tuning can be achieved and pit stop adjustments are more beneficial if your tire pressure gauge is accurate. Proper care and selection of tire gauges is the key to producing race winning accuracy.

Go Forward – Move Ahead

Jeff Butcher
Courtesy of JOES Racing Products
2/5/10
http://www.joesracing.com/

Corner Chemistry

2010-02-25T10:48:00.000-08:00

Who is right - the driver or the crew chief? Since I spent my racing career as a crew chief I would like to say crew chief yet I know corner chemistry comes for understanding when to allow the driver to prevail as well as knowing when to let the crew chief earn his reputation. Teams would be much better off to focus on communication and leave the ego and need to be right for congress.

Our goal is to have fast race car that can win every time it hits the track. Racers are competitive and the desire to win can create tension. Time is short during practice and the intensity relies on good chemistry to avoid communication strain.

While this article relates to the driver and crew chief as separate people, many of the concepts and thought processes apply if you are a driver that fills the crew chief role on your own. Curt Spalding of AllStar Performance is a successful dirt driver that is regarded as an excellent chassis guy. Curt points out that many short track racers act as their own crew chief. For those of you in this category, it pays to break down the corner as if you were explaining handling issues to another person. When considering adjustments it is beneficial to get out of driver mode and think through the corner section by section.

The best driver/crew chief combos have learned to communicate in a respectful fashion and have practiced how to transfer information to accelerate the decision process. The word “team” applies and the set up for the week begins in the shop. Communication in the shop has the luxury of time so it pays to think about alternate adjustments while in the relaxed atmosphere of the garage and prepare some options if the baseline set up comes up short.

Crew chiefs can help their drivers by “accepting” driver feedback. One time I was helping a new driver and I think I could have listened better. The track was old, flat, and bumpy - just plain wore out. Portland Speedway doubled as a drive in Movie Theater and it was always funny to see the movie speaker stands in the infield. Anyway, at one time Portland was a track where I really struggled as a crew chief and through hard work and plenty of trial and error I found some corner magic. My “found” set up was proven with two different drivers and I think my teams won about 7 races in a short span during our tour stops. We were the car to beat – good times. Our set up was certainly different and it was fun to have the outside the box ideas win consistently.

When I went to Portland with a new driver I had my proven set up and the confidence that we would go there and with a great chance to win. We got there and the driver whined about the car the through the entire practice and I was so bent on past success that I didn’t adapt to his feedback. I “knew” I was right and the car would be fast. I think we finished 25th 2 laps down. I learned a lot that day – so much for being right. The driver has to be comfortable in the car and the past doesn’t turn the steering wheel. I should have cultivated his feedback and “fixed” the car so it was drivable for him and his individual talent. He was a winning driver and the car was a winning car. Communication issues took a winning effort and made it 25th. Given another chance, I would have mounted the wheels on the roof to make the driver happy. From that day forward my goal was to hear the driver and make him comfortable in the car.

So how do you build driver and crew chief chemistry? Respectfully listening would be a good place to start. From there it pays to be business like in your approach to driver feedback at the end of each practice session. A routine that is followed creates a business like approach will reduce emotion allowing for the information transfer to be complete. Helping the driver to be relaxed will help him to provide digestible information. Aiming for digestible information transfer is something to think about – it is hard to fix a car if the driver says it is loose in, pushes in the middle and then snaps loose off. Break down the corner and go in sequential segment order after every practice session. Tire temps are worthless when the driver has every bad corner condition going on at the same time.

If a car is loose on entry then nothing else in the corner makes any difference. How can the car be good in the middle if the driver is afraid to turn the steering wheel? If the entry is bad the middle will be a challenge too and the loose in condition just about always causes a push in the middle. Focus on the entry first and manage each section of the corner in order. I like to break the corner into 6 categories and work on making the car feel good at point 1 first. I then go to point 2 and so on. If I get to point 3 and make an adjustment that makes point 1 unacceptable then I must start over. The corner sequence has to be followed. If point 1 is off the rest of the turn will be less than perfect.

My first 5 corner points are the Braking, Turn In, Middle (Apex), Acceleration and Exit. Below are my definitions for these areas but your team can use their own terminology if it helps to get everyone one the same page? My 6th corner section is overall comfort and drivability. A focus on a drivable car saves equipment and makes drivers very happy.

Point 1 – Braking

The braking area is the corner entry point were the driver gets off the gas and is hard on the brakes. The car begins to turn with a small degree of steering input. NOTE: The car must never be loose getting or it will be a handful for the driver. Drivers can adjust for cars that are tight in the middle or loose off. Loose in means the driver will just have to go slower.

Chris Stephenson is shown entering the braking point at Sun Valley Speedway. Chris is able to take the car in hard setting him good position for the rest of the corner.

Point 2 – Turn In

The Turn in is the point in the corner where the driver turns the wheel and pulls the car towards the bottom. Maximum brake pressure is transitioning to minimum brake pressure and by the end of the area brake pressure is at zero. Keep in mind that at every track these areas change and the end of the turn in area is where zero braking is found regardless of the actual geographical place in the corner.

Brad Dahmer is shown pulling the car aggresively to the inside line. A stable entry allows Brad to pull on the wheel with confidence setting him up for a good run to the middle.
Point 3 – Middle (Apex)

The middle is the point in the corner where the steering wheel is turned to the maximum amount. The car will roll through the center point. Brake pressure is at zero and the driver picks up the throttle to some degree which will vary from track to track.

Jason Knaus nails fast time at Lacrosse Oktoberfest. Notice how the LF tire is lower than the LR tire in comparison to the white line – driver’s should aim for feeling the LF lower than the LR. Jason’s car is really cutting through the middle just about guaranteeing a hooked up exit. The middle is the point in the corner where the steering wheel is turned to the maximum amount. The car will roll through the center point. Brake pressure is at zero and the driver picks up the throttle to some degree which will vary from track to track.

Point 4 – Acceleration

The Acceleration area is the part of the corner after the point where the car has taken a “set” and is pointed for maximum exit speed. The driver gets on the throttle in can see the exit.

Michael Hasitngs is shown getting on the throttle. The car is pointed after rolling through the middle creating a fast exit. The Acceleration area is the part of the corner after the point where the car has taken a “set” and is pointed for maximum exit speed. The driver gets on the throttle in can see the exit.

Point 5 – Exit

The exit area is where the car transitions from partial to maximum throttle. Some tracks have a second apex where the car can become loose under full throttle. The car is still turning and the straight is clearly in view.

Lee Smith Action Photos
Jay Smith is killing the exit and his car is launching down the straight. Stock Car guys would enjoy this much grip! The exit area is where the car transitions from partial to maximum throttle. Some tracks have a second apex where the car can become loose under full throttle. The car is still turning and the straight is clearly in view.

Point 6 - Driver Comfort

Driver comfort is a paramount goal. Many times you can have a car with knife edge speed. These cars are hard to drive and often the added speed disappears when the tires get hot or in traffic. Often I have dialed out knife edge speed in favor of a car that is more drivable. Sometimes the knife edge can be used for qualifying but for late models a set up that allows the driver to drive aggressively will result in more speed over the long haul. If you have to compromise and an earlier corner segment is off a bit it is ok to tackle the corner condition that makes the car uncomfortable for the driver.

Keeping the car comfortable is your paramount goal. Michael Hardin is using all his skill to save the car from knocking down the fence. Steering clear of knife edge set ups saves equipment and makes racing in traffic much more fun for the driver.

Here is an example of walking the driver through the corner breakdown process - if you act as your own crew chief the breakdown is basically the same:

Entry:

Crew Chief: Can you drive into the corner and feel the car is stable?

Driver: The car gets in good.

Crew Chief: How about when you hit the brakes hard? Still ok – no loose in feeling?

Driver: Yes – it’s getting in good even if I over drive it in.

NOTE: I train my drivers to make sure the car gets in the turn so they can drive aggressively. My teams know loose in is just not allowed and we will go to any length to make sure the car gets in deep and with a stable attitude every time. I am happy to make the driver nuts asking repeated questions about corner entry as we must be sure any possibility of loose in is eliminated. Yes – this is worth repeating several times!

Crew Chief:
Ok – we are getting in good. How about the Turn In to the corner. Can you turn the wheel with out fear and pull the car to the bottom aggressively? Does the car take a set and cut well?

Driver: Yes – I can turn it hard on the Turn In – all good.

NOTE: I teach drivers to feel like the LF is always slightly closer to the white line than the left rear in the middle. If drivers turn the wheel and get the car on the white line with the LF lower on the track then the LR you know the car is cutting well and the angle to the exit will allow the driver to hammer the throttle.

Crew Chief: Ok how does the car turn in the middle?

Driver – The car picks up a push in the middle. It just doesn’t cut. When I pick up the throttle it gets tighter and then when I get to the exit it snaps loose.

Crew Chief – Ok, let’s work on the middle. How do you feel about a quarter inch of additional stagger and raising the J-bar an inch?

Driver – It’s already snapping loose off – won’t that make it worse?
Crew Chief – let’s get it rolling through the middle. If we get it to cut through the center it will be pointed down straight. The wheel won’t be turned as much so it will hook up when we approach the exit at the right angle. Let’s focus on the middle first and see if the exit gets better when the car turns through the middle better.

NOTE: A car that is just a little tight after rolling though the center is easy to drive and fast. A car with a push in the middle is no fun. A little snug can help with a solid and stable exit. A car that pushes will make for a loose exit that gets looser lap after lap.

There are a million scenarios and your team can work the corner conversation focusing on each segment in sequence. Move back to the start if an adjustment upsets a prior segment.

Teams should also keep in mind the big picture when it comes to chassis adjustments. Sometimes you have gone too far and the so called adjustment rules no longer apply. During these times you end up doing the opposite of what the book says. If the car has a push it is common to use less RF spring. But what if you have gone down to a 5 pound spring in the front and the push is still there? In some cases more RF spring would help the car turn better. If you have gone to an extreme or then the opposite approach should be considered. Your choice to use a softer RF spring to cure a push is based on going softer than a predetermined baseline. Maybe the baseline was off? Be aware of those times when adjustments are not making sense. Perhaps you have gone through the adjustment center and you may need to go the other way with your thinking.

If your team spends the time to find common terminology while taking a systematic approach in communication cornier chemistry will automatically improve. Breaking down the corner into segments will make it much easier for the drivers to communicate what they are feeling.

Be completely aware at all times that the car must get through each section in order. A car that is loose in will just about always push in the middle. A car that pushes in the middle is often loose off. Drivers can explain a push then be worried about the car being loose sending their chassis adjustments off in the wrong direction. The cure is to break the corner down and only move on to the next section when the preceding section is spot on. If a change sets back a prior corner section then start the process from the beginning. Corner chemistry will be built due to your systematic approach resulting in more chances to spray Champagne.

Go Forward – Move Ahead
Jeff Butcher
JOES Racing Products
11/09/09
http://www.joesracing.com/

Why We Race

2009-11-30T13:24:00.000-08:00

A shimmering golden door hides a giant corporate machine that produces the next racing star of tomorrow. Once the door is opened the legendary machine guarantees racing fame and a long money filled career. Mesmerized, parents forget the comforts of home and stand in an endless line in hopes of placing their offspring in the proficient golden gadget located near a 2.5 mile oval Florida shrine. Reputation convinces parents to try and they are certain the elusive hardware will do all of the work instantaneously transforming their child into the next racing hall of famer. Nearly all youngsters would be better off honing their skills at their home track but Jeff Gordon, Tony Stewart and Kasey Kahne are rumored to be products of the wonderful machine. Jeff, Tony and Kasey know the golden door is a myth, yet history shows that the racing gods in Daytona Beach create new legends in lock step with the fall of an aging and once bright star.

Parents believe that when a young kid is given the key to the golden door the corporate machine can magically stamp out the next budding star of tomorrow regardless of their experience level. Many kids with whitened teeth and hair from the cover of Fashion Quarterly enter, but only one in a million emerges with the needed poise and skill of a true champion. With what seems to be an ever younger child inside, the pristine machine shakes, steams and vibrates working magic and applying mythical power to the chosen few. At last, a shot at the big time – it is all so easy or so says the legend.

Years ago I was at my home race track in Monroe Washington. Evergreen Speedway was located smack downtown and the grandstands doubled for racing and cow judging at the yearly fair. Richard Petty, Bobby Allison and Cale Yarborough were the racing gods of the day – corporate America allowed few gods back then. Legends in the era of black and white photography earned their time in the sun with actual grit, determination and plenty of beer.

By the age of ten I had been to the Evergreen Speedway many times. My dad would load me into his Chevy van with blankets to sit on and an Igloo cooler packed with his two beers hidden under a layer of ice and our PBJ sandwiches. Dad’s van was a true California special complete with crushed velvet seats and a stereo system that could rattle the windows out of an Army tank. Since we lived in Washington State, and not California, Dad’s ride really turned some heads. BF Goodrich T/A radials and 5 spoke mag wheels were the perfect accent to the airbrushed scallops that ran down the sides of the highly customized Chevy van. Riding to the track in style was a required part of racing back when I was ten. Mini vans weren’t allowed in the parking lot then. Little did I know I was learning why people race while chatting with my Dad on the 40 minute trip to Monroe.

We were regulars at Evergreen so even at ten I knew my way around. We sat in the exact same spot every week and nobody would even think of invading our turf. Eagerly, I would lead the family to the base of the grandstands turning left to look up at our favorite spot - 8 rows down from the top, 7 seats to the left of the isle and just past the start finish line. From there we had a perfect view of turn 1.

Turn 1 was where all the action took place and early in the year the turn 1 pond was still full - a beautiful combination of soupy water mixed with authentic northwest mud. Our bellies ached from laughter when drivers spun into the pond creating a giant brown splash. Thoughts of the billowing puff of steam filled the long Saturday night drive home with plenty of laughter. On special occasions, a rookie push truck driver would park too close to the pond and a muddy tsunami would cover his freshly waxed truck – real racing right here at home complete with material for America’s Funniest Videos.

Saturday nights weren't complete unless a couple unexpected racers got a shower in turn one. Racers that landed in the turn-one pond were usually unharmed. Mud on thier faces and bruised egos caused more damage than thier cars ever saw on the track.

Drivers and cars that landed in the pond were usually unharmed. The mud on their faces, a uniform dripping with puddle water, and egos that were more wet than bruised came standard with the admission price. The turn 1 puddle taught me plenty about why we race – it would just take me years to understand.

I fondly remember my favorite local drivers from back then. Real drivers that inspired me to get out of the bleachers and work on racecars were my idols. They had greasy uniforms, tussled hair and bad mustaches that would make them look more like adult film stars than racecar drivers. My visions resemble an old Elvis movie creating a dramatic contrast to current victory lane scenes with Kasey Kahne and his Budweiser Dodge sponsored by the Dodge Dealers in Gatorade Victory Lane at the Powerade Winners Circle celebration. Over the chaos of the celebratory noise you could hear Kasey say, “Which hat do I wear now?”

According to legend - in Kasey’s interview - he would utilize skills learned in the mythical machine. He would announce in his politically perfect voice; “I want to thank all of my sponsors, we had a really good car, the team worked super hard, the engine shop gave us a great engine and I am really proud of my team, my engineer, my PR guy, my mom and my dog”. It goes without saying that his dog is named “Charger”.

Amazing results - maybe the golden door really works! Sorry Kasey - I could have picked on anyone but since we are both from Washington I figure you would give me one freebie or maybe you would let me off the hook because my comparison to new and old is just “one of them deals”.

From our family Evergreen bleacher spot we could hear the announcer, well sort of. The thunder of the race cars muffled some of the words but back then my hearing was not yet hampered by the 100’s of times I would be in a closed garage with unprotected ears being bombarded with 8000 RPM’s and an engine guy that said he was setting the timing. I was never sure if the timing was set correctly or if it was just the engine tuners weekly playtime.

When ever the announcer mentioned my favorite figure eight driver I would perk right up. The loud speaker would crackle like an old scratchy LP - “….and starting on the pole - Dirty Dan the Sewer Man”. Funny how 35 years makes a reference to a sewer sound romantic.

Dan Knot was a racer. He raced for the pure fun. To him – Daytona was a post card with a white sandy beach and a bikini girl with oversize sunglasses. Mythical corporate machines not required. My Dad learned to be a chassis guy on Dirty Dan’s team and in true racer tradition he passed on all his knowledge to me. Dad taught me plenty.

Dirty Dan the Sewer Man somehow made a reference to a sew sound romantic. Dirty Dan (Knott) raced for fun - we all could learn from Dirty Dan.

My Uncle Bob turned wrenches on the Sewer Man’s car and he simply loved being around the track. Uncle Bob was a mechanic by trade. He could diagnose an engine simply by holding a screw driver over the intake - no need for one of those big fancy red boxes with a TV screen on it. Uncle Bob could simply listen to the engine and with the experience of real grease under his fingernails he could have you back on the road for a few bucks, a cold beer and a have a nice day smile – those were the days!

Dirty Dan had plenty of company. Ben Chandler, The Wizard, would add a certain color to the festivities making sure everyone in Monroe had something to cheer for. Crazy Carl Zaretske would smash the gas on and off through the turns of the Evergreen Figure 8 track. Carl had his trademark driving style. Whomp, whomp, whomp – you could hear the throttle pedal go to the floor about 8 times in each and every turn. To Carl, being smooth was saved for flirting with female groupies in victory lane.

Crazy Carl Zaretske was instantly recognized with his maroon 57 Chevy and the hand painted No. 2 on the side. Crazy Carl would stomp the gas on and off through every turn as he muscled his way to the front.

Why would Dirty Dan, Uncle Bob and my Dad race so hard when the mythical golden door and corporate machine was not even on their radar? Was it the time in the shop away from real life? Maybe it was the relaxation of building a mechanical marvel – figure eight cars were pretty cool! In what other sport can you dress in tacky oil stained uniforms and be rewarded with a crazed crowd that cheers wildly at every wreck, fist fight and photo finish? Perhaps it’s the camaraderie? The junior writer from the Seattle Times would just say it was for the love of the sport - he had no idea - the night before he was covering a high school chess tournament. Being low man on the totem pole meant he did all the bottom of the barrel assignments. Journalism at it’s best!

Maybe we race as the universal goal of competing creates a common racers’ bond – a bond so powerful that Saturday night at the track is more important than friends, weddings, anniversaries and kids birthdays. Respect strengthens the holding power of the Saturday night ritual and even the toughest competitors and bitterest of rivals treasure the compelling power of the racing bond. Every true racer feels remorse - but wouldn’t think of showing any sign of emotion - when their enemy’s auto show perfect machine meets with an untimely concrete collision.

Racing is so unique that it has its own language – mess with us and we will fire a warning shot - fool with us and we will take off your head. True racers can spend an entire evening in the shop and speak volumes with out uttering even one audible word. In a racer’s shop, there is a poetry of information that is often spoken with a single head nod, a curled eyebrow or a subtle shoulder shrug. Clattering wrenches keep rhythm with the cycle of the week – Saturday night comes each and every weekend during racing season.

Drivers too have their own silent language. Chrome horns spank the child in front of them and hand gestures wave a thousand messages to those passing by. A subtle right turn leaves a tire mark on the competitor’s door – a rubber zero clearly communicates the opinion for the duration of the night. Those who push the window too hard are given a firm squeeze into the outside wall shortening one day and lengthening six nights.

From the comfort of the crushed velvet seat in my Dads’ van and the fabulous puddle in turn 1, I learned that we simply race for fun. True racers know that just having fun is reason enough to sacrifice normal behavior in exchange for another Saturday night fix. Since we are all still ten at heart, why look for the fickle and elusive golden door and corporate magic? If we want clean fun we just need to remember Dirty Dan - he had fun – he found gold right here at home.

Go Forward – Move Ahead
Jeff Butcher
JOES Racing Products, Inc
10/09/09
http://www.joesracing.com/

Roll Center Magic

2009-11-30T09:14:00.000-08:00

Dialing in your Front Roll Center could be the magic difference that makes your car prevail in the center of the turn. But, is it really magic? I think that many times we over analyze Roll Center when really it is just another adjustment. We throw springs at the car and make shock changes. We adjust the bite and stagger on a whim. Changing the Front Roll Center at the track is crazy talk – or is it?

For perspective – we often move the Rear Roll Center in a care free trial and error fashion. If the car is loose it is common for teams to simply move the Rear Roll Center down by lowering the panhard bar or j bar an inch or two. Teams on TV or at your local Saturday night track move the Rear Roll Center just for fun and then move it back if the driver doesn’t like it. We move the Rear Roll Center up and down and really do it with out over thinking.

When it comes to the Front Roll Center - it seems we have to consult witch doctors from Zimbabwe before we can think about making a change at the track. The misconception is that if a team were to change the Front Roll Center at the track then an ancient taboo would curse the team for the entire season.

The Front Roll Center is a point in space that is derived from the LF and RF Instant Centers and thier relationship to the contact patch.

Really, Front Roll Center adjustments at the track are easy if performed with a little thought and reasonability. There is no mystery and while we are happy to move the Rear Roll Center all over the place we seem to be afraid of Front Roll Center adjustments at the track. In actuality, you could consider lowering the Front Roll Center at the track to rid the car of a nasty push just the same as you would raise the panhard bar or j-bar to cure the condition? Really - you can. Just do it. If the driver likes the change then your team has found some new speed – if not then undo the adjustment with the same amount of thought as you put into moving the j-bar/panhard bar.

To help us become okay with making Front Roll Center trackside changes it pays to have a basic understanding of Roll Center both front and rear. Rear Roll Center is easy to understand as there is a physical part such as a j-bar or panhard bar for us to see. The Rear Roll Center is easy to calculate. Rear Roll Center is the average of the inner and outer mounting point heights at the center of the left and right mounting locations. Rear Roll Center may be easy to understand but in the end we just move it to adjust the car and then move it back if the driver complains. So simple.

The Front Roll Center can be confusing because on paper there are a bunch of lines going every which way. When the car goes through dynamic roll the lines go crazy as the pivot points move quickly which can give racers a headache – static front roll center is hard enough to comprehend but the data gets insane when you roll the chassis. But – what if we simplify the way we think about Front Roll Center? What if we view Front Roll Center like we view Rear Roll Center?

To simplify the Front Roll Center thought process it helps to understand the creation of the so called magical point. Front Roll Center is a calculated point verses a physical place. To find it you must first locate the Instant Center both left and right.

The RF Instant Center is found by drawing a line through the center of the RF upper A-Arm ball joint extended out though the center of the A-Arm inner pivot point on the frame. Another line is drawn from the RF outer ball joint center though the lower control arm frame pivot. The lower control arm line is extended out until it meets the upper control arm line. Where these lines intersect is called the Instant Center. The LF Instant Center is found in the same way.

Instant Centers are much easier to visualize than Roll Centers. The Instant Center is simply the point where the upper control arm pivot point and the lower control arm pivot point lines intersect.

After the Instant Centers are located you can now find the Roll Center. From the RF Instant Center you draw a line back to the RF contact patch center. From the LF Instant Center you draw a line back to the LF contact patch center. Where these two imaginary lines cross is the Roll Center.

Car designers spend a ton of time figuring out mounting points and control arm lengths to come up with their idea of the optimal Roll Center. That said – Roll Center is just a point in space and there is little preventing you from moving the Roll Center around to find more speed. Sure, you shouldn’t go crazy but you can make reasonable and common sense adjustments quickly at the track.

For example – let’s say your car has a push and you tried raising the Rear Roll Center to free the car up. The driver didn’t like the change and now you want to try something else. You could adjust the bite, add stagger, soften the RF spring etc. OR – you could lower the Front Roll Center. You could just change the Front Roll Center by thinking out the variables just like you do at the rear. At the track, you could simply raise the RF A-arm inner pivot point. Raising the RF inner pivot would move the RF Instant Center down resulting in the Roll Center moving down and over to the left. The result is similar to having a softer RF spring through the timing of chassis roll.

Increasing the angle at the RF upper A-Arm raises the Front Roll Center and moves it to the right.

In order for the Front Roll Center track adjustment to be practical, it pays to worry less about the detail of the specific Roll Center location and focus on the Instant Center and your goal for the chassis adjustment. If you use a RF A-Arm frame mounting plate that is slotted for height adjustment you can use slugs to ensure you have repeatable and documentable changes. The idea is that you when move the rear roll center down a half inch you have something solid and repeatable to record in your set up book. For the Front Roll Center adjustment you can simply record that you moved the RF inner A-arm mounting point up a half inch with a slug. By understanding Roll Center and all the magic lines you can use your understanding to simplify the process at the track allowing for easy and practical changes. Changing a slug is pretty easy for a trial run and it is easy to repeat. If the driver doesn’t like the adjustment you can simply bolt the original slug back in and look for the next piece of hardware to move in your quest for more speed.

When would you try raising the RF A-arm pivot which results in a lower Roll Center? All adjustments are about timing. When and how does the car roll and what effect can we have on the timing of the chassis roll to make things occur at the right point in the corner? The ultimate goal of knowing the specific time in the corner to have the suspension move is the ultimate set up secret. If we truly knew how and when things move in the corner we would always have the fastest car! Since we don’t truly know - we gather all the information we can find from drivers, pyrometers, data acquisition or whatever and apply our experience to cut down the trial and error process. Even the guys on TV, that have unlimited access to money and engineering, are still in the position of using trial and error.

You can think about a trackside Roll Center adjustment if you wanted the car to experience stiffer front springs under braking yet have the front springs feel softer in the center of the turn. In the end – your decision making is just like the rear roll center process. When do you decide to move the rear j-bar up or down verses making a spring change? A Front Roll Center adjustment thought process is basically the same thing. Just move it!

We can easily move the upper pivot point of the front A-arms to reach a desired goal. Again, trial and error is part of the equation but the mystery of the Front Roll Center shouldn’t stop us. Moving the A-Arm pivots at the track is easy if you have the right hardware. Slotted A-plates and slugs work great.

Using and A-Arm slug to adjust your A-Arm inner pivot points gives you an easy and repeatable way to adjust your Front Roll Center right at the track.
You can move the lower points too, but you bring in rack location issues and bump steer corrections. If you take the time in your shop and know which rack spacers and lower pivot slugs to use at the track you could bolt in the new slugs quickly giving you more options. Your options need to consider camber change curves, static settings and bump steer effects. Changing the lower angles relieve you of camber curve considerations but are more time consuming so a focus on the upper A-Arms may be the best trackside compromise?

A slotted A-Arm plate allows you to use slugs to make Front Roll Center Adjustments at the track giving you another weapon in your adjustment arsenal.
Lowering the RF A-Arm inner pivot raises the Front Roll Center and moves it to the right. Negative Camber is added and may need to be reset.

Raising the RF A-Arm inner pivot lowers the Front Roll Center and moves it to the left. Negative camber is reduced and may need to be reset.

Lowering the LF A-Arm inner pivot raises the Front Roll Center and moves it to the left. Positive camber is reduced and may need to be reset.

Raising the LF A-Arm inner pivot lowers the Front Roll Center and moves it to the right. Positive camber is added and may need to be reset.

An adjustable ball joint uses shims to change the A-Arm angle for quick Front Roll Center adjustments right at the track. A-Arm height an angle adjustments can be made just at the ball joint or in conjunction with inner pivot slug adjustments.

To further illustrate the point, I think that Front Roll Center is a design parameter that involves plenty of engineering and thought. I also think that if you have a basic understanding of Roll Center geometry that you can short cut the thought process at the track and simply focus on the LF and RF Instant Centers. At the track – you can easily visualize the effect on the RF instant center if you raise the RF a-arm inner pivot ½”. At this point in time you car is already “engineered” and you can just make the adjustment. By focusing on the Instant Centers you can readily make repeatable adjustments without having to worry about a bunch of imaginary lines. You can understand Instant Centers and their location quickly and easily. The reality is that Front Roll Center is simply a derivative of the Instant Center locations. Instant Centers are simple even through dynamic roll. Why complicate your trackside thought process with imaginary lines? Save the heavy thinking for the engineering room. At the track - just give it a try!

By understanding the Front Roll Center parameters and the imaginary points you can simplify the process and easily document which slug you are using to adjust your a-arms up and down. Focusing on Instant Centers makes it possible at the track. With this simplified thought process you can add another weapon to your adjustment arsenal and make adjustments that gets you ahead of your competition.

Go Forward – Move Ahead
Jeff Butcher
JOES Racing Products
10/01/09
http://www.joesracing.com/

Three Link Lessons

2009-10-14T10:17:00.000-07:00

Have you ever driven a fork lift or other hot rod that had the steer wheel in that back instead of the front? Rear steer rigs turn quickly and the term “push” just would never apply. Understanding your three link suspension can give you adjustment tools to help you roll through the center of the turn or help to hook you up on exit.

In general your static rear setting should be dead square. In your shop you need to spend the needed time to ensure that your rear end is exactly square. Once your rear end is square it helps to record the measurement from a brake rotor to the frame as well as from the trailing arm brackets to the frame both left and right. Keeping these measurements on hand will allow you to make track changes with the confidence that you are maintaining a square rear end setting.

All of my shop set ups include a rear end that is absolutely square. It is always my goal to maintain a square rear end and use all the other adjustments to find the right set up. I always feel that changing the square is a crutch that can create late race handling problems and potentially make your late race tires under perform.

Clamp on aluminum trailing arm brackets allow you to set the trailing arm angles to help your car turn through the center. You can arrange your three link set up for over steer or under steer through chassis roll. Experienced crew chiefs use the three link set up as part of their set up package.

While I try to avoid messing with the rear end square it is an amazingly effective adjustment. Drivers always provide instant feedback and a rear end square adjustment is felt instantly. If you have a car that is loose in that condition must be fixed. Drivers can adjust their line for a center push or exit loose but entry loose means you simply have to lift sooner.

If you toe in your trailing arms at the front you can use the J-Bar to help over steer the rear end to cure a push in the middle. In this example, mounting the frame side of the J-Bar higher than the pinion side moves the rear end housing to the left as the chassis rolls. As the housing moves left the RR trailing arm gets longer and the RR tire moves back helping the car to turn.

If I have exhausted my reasonable loose in adjustment ideas I might choose to shorten the RR trailing arm an 1/8” to help cure the loose in condition. Often moving the RR ahead cures the loose in condition but you run the risk that the fix is short term. It is possible that you could get a late race center push or the loose in condition could return after the tires heat up and wear a bit. Experience at a given track plays a big role here.

On some days it seems that the push in the center won’t go away. Again, I try to avoid messing with the rear end square and go through all of my other ideas before moving away from square. To place this concept in perspective I would say 95% of the races I have ever been around in involved a square rear end. I would say I got a nice handling improvement about half the time that I moved the rear end and saw some or little improvement the other half. Hey, sometimes you miss the set up and it is what it is.

If the car has a push in the center then I might shorten the LR trailing arm 1/8”. It would be rare that I would recommend going more than an 1/8” and really I will stick with the thought that square is best 95% of the time – maybe even 98%.

You can think out your rear link set up and by understanding how and when the car rolls you can use the trailing arms to help dial in your set up. When using trailing arm angles to help your set up it pays to truly understand the movements at each section of the corner as well as think about any drawbacks that rear steer or under steer might create.

To help the car turn through rear steer you can run the RR trailing arm uphill a ½”- 1” at the front. As the car rolls the RR trailing arm will push the rear end housing back on that side. The uphill RR trailing arm adds anti-squat to the car which helps forward bite under acceleration so I like to run some uphill angle in the RR trailing arm. Maybe a ½” up is a starting point.

To really add over steer at the rear end housing you can mount the front pivot point of the RR trailing arm towards the center of the car. With the trailing arms toed in at the front you can use the J-Bar mounting angle to help steer the rear end through roll. If you run the frame side of the J-bar is higher than the pinion side the rear end housing moves left through roll. As the housing moves left the RR trailing arm gets longer and pushes the RR tire back producing rear steer that will help the car turn.

If you want the rear end housing to under steer then mounting the RR trailing arm level and perpendicular to the rear end housing will produce the desired result. As the car rolls the RR Trailing are will shorten pulling the RR tire ahead.

When it comes to trailing arms I try to avoid linkage arrangements that go though center under roll. In other words – if the trailing arm starts on an uphill angle I do not want it to go past level and then head downhill. If the travel was enough to create a down hill angle under full roll I would make an adjustment as this can make the care unstable. I want to avoid having the RR tire to move back and avoid having the trailing arm travel through level which would cause the RR to begin moving forward.

Typically, I like run the LR trailing arm up hill about ¾” to 1”. There is much debate on this but I like to have a little anti-squat in the car to promote bite under acceleration. If you run a high amount of wedge then level may be a better idea. Since the left side is lifting in the corner the angle increases and the LR trailing arm shortens and keeps moving in the same direction. Again, when it comes to trailing arms I try to avoid linkage arrangements that go though center under roll as going through center can create an unstable car.

Mounting the LR trailing arm with the inner pivots towards the center of the car coupled with the J-Bar running downhill from the pinion to the frame will pull move the LR tire back during roll promoting under steer.

By thinking out the trailing arm angles in conjunction with the J-Bar angle you can guide the rear end housing on the path that helps your set up through the turn. Running the J-Bar higher on the frame side will push the rear end housing to the left through roll. If you run the frame side lower or level the rear end housing will move right through roll. Using the J-Bar mounting angle to in conjunction with trailing arm angles both up and down and left to right gives you another tool in your arsenal helping you to achieve faster lap times.

A slotted pinion mount allows you to quickly set the J-Bar angle. Running the J-Bar higher on the frame side as compared to the pinion side moves the rear end to the left through chassis roll. Understanding how the rear end moves gives you adjustment options to dial in your set up for added speed.

Using trailing arm brackets with multiple trailing are mounting holes gives you additional adjustment options. The clamp type aluminum brackets allow you to mount the trailing arm left to right mounting location where ever you want. You can fine tune the trailing arm location and trailing arm toe settings by using spacers to set the left/right angle to meet your needs.

I recommend running the top link with a fair amount of anti-squat built into the adjustment and a downhill angle of around 4 to 7 degrees. If you run a track where the car is tough to hook up you can get some added bite to the LR under acceleration if you mount the top link closer to the LR wheel. If a track you run is consistently tight then mounting the top link closer to the RR will free the car up under acceleration.

A top link mount that is slotted will allow for ultimate fine tuning of your top link anti-squat settings. Top link mounts with multiple holes also work well. Adjusting the anti-squat for your car, driver and track can maximize exit grip getting your team to the finish line first.

Top link mounting ears with multiple holes or slots will give you more room for adjustability. You can choose mounting ears that have the adjustment holes offset behind the center line of the rear end housing which will add more anti-squat under acceleration. Keep in mind that anti-squat only takes advantage of the available grip through the use of mechanical leverage. Excessive amounts can cause a loose in condition or wheel hop. Occasionally the driver might report that the front wheels feel light under acceleration at the late apex point – if so you should dial back the top link angle and anti-squat for driver feel.

As a general guideline – more anti-squat in your three link suspension works best if you run low amounts of wedge. As wedge numbers increase then you should consider lower amounts of anti-squat. Again, you can make adjustments based on your set up. I prefer low amounts of wedge in an asphalt late model and most of the races that landed my teams in victory lane had 49% to 53% of diagonal. Based on those lower wedge settings I would run a fair amount of anti-squat. Typically, I would run the LR trailing arm up an inch on the front. By using the trailing arm with plenty of angle I could reduce the angle in the top link creating a more stable entry while maintaining the anti-squat I desired. If you run 60% diagonal then running the top link and trailing arm closer to level is a good starting point.

Using your three link suspension to dial in your car is a viable adjustment option that can be performed quickly right at the track. The teams that experiment with the proper three link set up can find the set up that launches their car off the corner with more acceleration to get to the checker first.

Go Forward – Move Ahead
Jeff Butcher
JOES Racing Products
09/01/09
http://www.joesracing.com/

Driver Performance

2009-09-11T13:28:00.000-07:00

A fresh driver that is fitted comfortably to the car will have more energy to beat the competition during those long summer races. Paired with a fast car the driver that prepares to win can place himself above the crowd in simple fashion.

The first step is to ensure that your driver is comfortable in the seat. It may take a few tries and some extra fabrication but the effort is well worth it come lap 125. Seat position is extremely important and spending the time complete with ample driver feedback is essential. Pedals should be within easy reach to allow for a relaxed leg position. Shifters should be ergonomically located with radio switches in easy reach.

Mounting the steering wheel as close to the chest as possible will prevent back strain and keep your driver up on the wheel for the entire race. A larger steering wheel creates more leverage so I always recommend the largest steering wheel that will fit past your driver’s mid-section. Utilizing an adjustable steering column allows the driver to adjust steering position right from the seat allowing for fine tuning and ultimate driver comfort.

Using an adjustable steering column mount will allow the driver to adjust the steering column with a quick adjustment right from the seat, allowing for optimal driver comfort.

Using the largest steering wheel possible will increase leverage and make the car easier to turn late in the race. Mounting the steering wheel as close as possible to the driver's chest relieves pressure off the lower back.

A large drink holder will provide needed liquid helping to keep your driver in good condition throughout the event. A drink holder with a bite valve prevents siphoning so that a cool drink is available the entire night. Be sure that the drink canister is thoroughly cleaned after each event verses leaving un-used sports drink sitting in the container all week.

Be sure to clean the drink holder after each race verses letting liquid become rancid during the week.

Head rests and leg supports should be fitted to keep the driver relaxed. Care should be taken and an exit route should not be hampered by cockpit amenities. Vision is a top priority and easy access to mirrors will help your driver to see at critical moments. Side mirrors and wide view rear view mirrors are needed to increase driver awareness. Some people debate the side view mirror. In my view there is zero debate – you absolutely need a side view mirror.

Mounting the pedals so that the driver's legs stay relaxed will relieve fatigue and give the driver the energy to stay up on the wheel for the entire night.

Driver preparation begins with exercise and a pre-race meal habit that is designed for performance. Good nutrition is a full time project and eating right only on race day comes up short as compared to a proven meal regiment.

Daily hydration would include 80 ounces per day of water or sports drink. Competition hydration should start at least 48 hours before race day. On the evening before race day drink 16 ounces of your favorite sports drink before bedtime.

Eating quality food and skipping the fast food line will help you and your crew to stay sharp. Making a shopping list and a quick trip to the grocery store will put reasonable nutrition at your finger tips.

On race morning drink another 16 ounces of sports drink or water. If it is a day race drink an additional 16 ounces 2 hours prior to the event. For night races drink 16 ounces of sports drink 2 hours before the event and add and additional 16 ounces in the middle of the day. To assist in the hydration process, drink the liquid in large gulps verses sips.

During the event it is important to maintain hydration. 4 to 8 ounces should be consumed every 20 minutes. During the race a sports drink with a carbohydrate component will help maintain energy from green to checker.

Post race hydration is an important element helping the driver to recover and proper post race hydration starts a healthy cycle for the following week. With in an hour after the race drivers should drink 24 ounces of water or sports drink and continue through out the week with ample liquid intake. Drivers that sweat excessive amounts should replenish with 24 ounces of liquid for every pound lost during competition.

Caffeinated beverages should be avoided in the 48 hours before a race. Alcohol should be avoided in the 48 hours before race day as well. Cool water is absorbed by the body more efficiently than warm water – somewhere around 55 degrees seems to work best.

Proper race nutrition will help keep your driver in winning position. Foods high in carbohydrate provide the needed energy for endurance. The science states that carbohydrates fuel muscles and they breakdown it smaller sugars providing the energy for optimal performance. The sugars glucose, fructose and galactose are stored in the body. These sugar stores prevent muscle tissue breakdown during competition.

Energy bars, energy drinks and fruit are a good source of carbohydrates. Pasta, rice and bread contain needed carbohydrates and racers looking for an edge should load up 48 hours prior to grueling races. On race day a solid meal 4 hours before the race will provide valuable energy and give the body time to reap the benefits. A complete meal should be followed up with a sports drink one hour before the race.

Eating food high in protein completes the racers diet. Foods such as Beef, chicken, fish, milk, cheese, peanut butter and eggs are the choice of top racers. Champion racers eat a balanced diet of high protein foods to stay sharp. Protein repairs and rebuilds muscle fiber and assists in carbohydrate storage.

Fat is a needed ingredient in the sports diet but fatty foods should be avoided on race day as the body takes a long time to covert fat into energy. While tempting, racers should avoid donuts, burgers, meats, fries, chips and candy bars on race day. The fat content takes the body a long time to digest and the slow digestion diverts energy at game time.

Racers should stick with proven foods on race day. Each body is different and experimenting with a new food routine on race day or even the day before could lead to nausea and discomfort at the worst time. All athletes should pay attention to their bodies and only eat foods that they know will agree with their system.

Eating right just on race day will not produce competition results. A solid routine starts early in the week and peaks on race day. Exercise will assist the body in converting food into energy and a fit driver will excel regardless of the conditions. Helping your driver to be healthy is as important as the winning set up. Keeping your driver up on the wheel for 200 laps will create more wins. Really, the entire crew will be more efficient if they prepare their bodies with as much effort as they place on the racecar.

Below is a loose meal plan that has been tailored to be practical for racers. Olympic athletes follow a strict diet that would simply be too hard to follow for most racers and their teams. The suggestions below are designed to be obtainable for the racing crowd.

Sunday (Recovery Day)

Breakfast - Eggs, non fat milk and English muffin w/peanut butter

Lunch - Tuna sandwich, celery, pretzels

Dinner - Flank steak, red potatoes, peas, salad, apple juice

Monday

Breakfast - Grapefruit, whole grain cereal, non fat milk, cheese stick

Lunch – Turkey sandwich, oven baked Tostitos, apple

Dinner – Boneless/skinless chicken breast, pasta, string beans, salad

Tuesday
Breakfast – Oatmeal, low fat cheese, non fat milk, orange

Lunch – Roast beef sandwich, pretzels, yogurt

Dinner – Fish, brown rice, broccoli, mixed green salad, V-8 juice

Wednesday

Breakfast – Eggs, English muffin, orange

Lunch – Burrito, apple, V-8 juice

Dinner – Boneless/skinless chicken, corn, pasta, salad, juice

Thursday

Breakfast - Cream of Wheat, strawberries, toast with peanut butter, orange juice

Lunch – Burger, grapes, sports drink

Dinner - Pork chop, brown rice, peas, salad w/shrimp, apple juice

Friday

Breakfast – Eggs, toast with peanut butter, grapefruit, V-8 Juice

Lunch – Chicken salad sandwich, apple, pretzels, sports drink

Dinner – Spaghetti with tomato and meat sauce, garlic bread, cauliflower, salad, water

Saturday (Race Day!) - Recommended competition day food suggestions per the American Dietetic Association:

4 hours prior to the race

Fresh fruit
Fruit and/or vegetable juice
Bread
Pasta with tomato sauce
Baked Potato
Energy Bars
Cereal with low fat milk
Low fat Yogurt
Toast with peanut butter, lean meat or low fat cheese
30 oz of a sports drink

2 hours prior to the race

Fresh fruit
Fruit or vegetable juice
Breads
Low fat yogurt
Sports drink

1 hour prior to the race

Fresh fruit
Fruit or vegetable drinks
12 oz of energy drink

Within 1 hour after the race

Energy bar
Sports drink
Fruit

Within 2 hours after race

A complete meal

Between meal Snack ideas:

Fruit (Blueberries, apples, oranges, bananas, grapes, strawberries, raspberries, peaches), celery, pretzels, oven baked chips, soft corn tortillas with non fat cheese, low fat low sodium crackers with peanut butter, low fat yogurt, whole grain cereal with non fat milk, peanuts, almonds, sunflower seeds, non fat cheese sticks, Wheat Thins, Ritz, and Triskets.

A driver and crew that are well fed on a diet other than hot dogs and beer will be able to prepare the car and find ideas to keep the driver comfortable in the car. Proper diet and hydration will allow your team can take advantage of the winning set up by keeping the driver up on the wheel when the competition wears out. Eliminating fast food and replacing high fat foods with a reasonable diet requires simple pre-planning and can be easily adapted by any team. A quick trip to the grocery store will make quick trips to victory lane a repeatable healthy habit.

Go Forward – Move Ahead
Jeff Butcher
JOES Racing Products 8/1/09
http://www.joesracing.com/

Setting The Bar

2009-08-10T16:00:00.000-07:00

Evolution in racing has created new set up options. Installing and adjusting your sway bar correctly will help you to achieve repeatable speed. Whether you run a standard 1 1/8” bar or a 2” big bar you team should have a reproducible routine to ensure the bar is loaded as anticipated every time.

Whether you use a standard one-piece bar or a three-piece big bar, your sway bar will work more efficiently if you mount the link that connects to the lower control arm at 90 degrees.

Upon arrival at the track and with your car race ready it really pays to set up your scales on the most level ground you can find. Shim the scale pads if needed and mark the pad location so that you can weigh the car at the track in the same spot. Once the scales are set up, weigh the car and record any difference that might be created due the track ground not being level as compared to your shop set up. By establishing a baseline at the track, you will be able to make adjustments and use your baseline to maintain proper loading of the bar, ride heights and wedge. An established baseline will help to get you back to your desired numbers even after many trackside changes. Check the sway bar at the track, with the car on the scales, and note any difference in preload as compared to when you set the bar in the shop.

With a standard 1-1/8” bar and your car in race ready condition I recommend setting the sway bar on perfectly level ground. Race ready means that the next thing your car does is head right on the track. Full of fuel and everything set. Your shop should have marked places on the floor so that the car is weighed in the same level place each time. Spend the time to make the scale pads are perfectly level in your shop.

Setting the bar on the scales allows you to verify that the wedge is set to the desired number every time. With a standard set up and 1-1/8” bar setting the bar with the driver in the car works best. When the driver is in the car you make your adjustments accounting for the 12 pack of beer and large pizza your driver consumed during the week. Set your ride heights, stagger, air pressure, front to rear balance, and wedge. Be sure the fuel tank is full. If you run high rebound adjustable shocks make sure to open them up for the set up routine or have a set of dummy shocks of the same brand that are used only in the shop for set up purposes.

Personally, with a 1-1/8th inch bar I recommend loading the bar ½%. Many teams choose to run the bar neutral which is just fine. I always felt that the ½% preload helped the driver get into the corner. If your driver is smooth, and your corner transitions are modest, then neutral can help keep the care free in the middle. You can create your own preload setting and adjust as needed at the track but having a routine is the goal.

With a big-bar Mike Leary of Leary Racing Shocks recommends adding wedge to the car by preloading the bar. Leary sets the wedge in the springs and then adds additional wedge with 3-6 turns of preload and sometimes has winning success using 9 turns. There is some debate here as some chassis experts think big bars are too sensitive and they prefer to run them neutral - Chuck Carruthers is in this camp.

With a big 2” bar there is debate on how to establish a set up routine. I see teams that have their crew jump on the front bumper to get it down to the stops where they then set the bar. This may work for some teams but I think there are too many variables for this procedure to be consistent. Even with a big bar set up, I recommend setting the bar at ride height. Mike Leary of Leary Racing Shocks likes to use the big bar to add wedge to the car. Mike recommends setting minimal wedge in the springs and then adding 2 to 4 percent of additional wedge in the bar to reach your desired wedge total.

If you are running a bump stop set up west coast set up guru Chuck Carruthers recommends pulling the springs and letting the car sit down on the stops. Chuck then sets the bar neutral with the car on the stops and with the driver in the car.

The one time it might make sense to have your crew stand on the bumper is when you are running a LF coil bind set up. Setting the bar with the coils bottomed out provides for fixed compression against a solid surface. If you run coil bind in the front, Carruthers recommends loading the bar 3-5 turns once the coils have reached the bind point. Coil bind set ups are really reserved for teams that can afford testing to work out all the bugs.

Using a frame rail slider system to mount the sway bar allows you to move the sliders for perfect sway bar alignment with the lower control arms reducing binding and increasing consistency.

Mounting your sway bar properly is very important. Ensuring that attachment points run 90 degrees and are free from binds helps to keep your car fast. Awkward angles can create binding through travel making car performance unpredictable.

Utilizing bushings to support the sway bar in the bar eyes is a vast improvement over letting the bar grind against old style steel sway bar eyes. Installing slider sway bar mounts on both frame rails allows you to adjust the bar location so that your bar stays lined up even if you switch to different length arms giving you more adjustability in your car. Some sway bar arms have multiple holes to connect to the lower control arm. Shortening the sway bar arm increases the effective bar rate and with the slider bar mounts you can move the entire bar to keep the links 90 degrees for optimal performance.

Using sway bar eye bushings keeps your bar running smoothly and eliminates binding. A swivel eye self adjusts for perfect alignment. This swivel eye is removable allowing the bar to be dropped out the bottom for quick sway bar changes.

Swivel adjustment eyes allow you to use a ratchet to load the bar making for quick and easy adjustments. The swivel system allows you to preload the biggest bars with ease. The swivels prevent binding and self adjust keeping in line with the bar. Quick sway bar changes can be made as the swivel eye unbolts allowing the bar to be dropped out the bottom.

Adding preload to a sway bar effectively increases its rate. If your team feels you need a bigger bar you can wind in some load to see if you are going in the right direction before spending the time to change out the entire bar. Moving the sway bar links just one hole has a profound effect and is another adjustment option.

If your car is a little loose on entry then adding preload to the bar can help to settle it on entry. A bar that is neutral or set slack can, at times, cause a loose entry condition. A quick preload adjustment can be made during practice and your driver can give you an instant report. My feeling is that race teams should do everything in their power to avoid a car that is loose on entry. If your car is tight in the middle the driver can compensate with a different line to help minimize the push. With a loose entry condition the only thing the driver can do is to slow down. Loose entry should be avoided at all costs and in this condition winding turns in your sway bar may be good fix.

Choosing the right bar is difficult. The best way is to consult with your chassis builder and simply watch what your competition is doing. At many tracks it remains to be seen if the new big bar concept is better than the traditional bar set up. Most crew chiefs agree that the big bar set up is good when you hit it. The offsetting factor is that the big bar concept is finicky and you can be out to lunch as soon as the smallest variable is introduced. For less experienced drivers a standard bar set up is going to produce more feel helping them through their learning curve.

Whether you use a standard bar or a big bar establish a routine so that your sway bar is set the same way each and every time. When you preload a sway bar the increase in rate is exponential as you add turns of load. Teams should experiment with the car on the scales and record the wedge number increase with each turn. Charting the wedge change with each turn of preload only takes a few minutes and it will give teams the information they need to make precision changes at the track.

The bottom line is that a smooth operating sway bar that is installed free of binds will make your car faster. The precision parts available today offer an advantage. In the past, one piece sway bars were simply bolted in and taken for granted. Your team can find consistency and extra speed by tuning up your sway bar installation coupled with a sound routine for loading the bar.

Go Forward – Move Ahead

Jeff Butcher
JOES Racing Products, Inc
7/1/09
http://www.joesracing.com/

Short Track Aerodynamics

2009-07-06T13:49:00.000-07:00

Short track racers can create more down force than their competition by spending the time to take advantage of the leeway permitted by fiberglass bodies. Corner speed can be improved by the teams that massage the body panels and push the limits of the rules. Depending on your division, there may be significant down force gains due to the lack of templates and/or enforcement. Cup teams have to live with the Car of Tomorrow and have less room than ever to stretch body panels. Short track late model teams have plenty of room to achieve maximum down force.

Down force is your friend. Just about all late models run on tracks that are under a mile in length. Corner speed is enhanced by applying every trick to create down force as drag is of little consequence for short tracks. Occasionally, race teams have asked me if they should lay the rear spoiler down on larger tracks to reduce drag. In general, you want the maximum spoiler angle allowed up to about 75 to 80 degrees on tracks 1 mile and under. More spoiler angle creates down force at the rear wheels helping to launch you off the corner. With the good initial run off the exit the engine horsepower gets your car off to a good start and the added drag on the straight is not worth considering. If more spoiler angle lets you get the throttle to the floor sooner then you will go faster and the effects of drag on the straight are not enough to take away the solid start off the corner.

Keeping your spoiler in the wind with plenty of spoiler supports will add consistent down-force at the rear wheels, helping to launch you off the corner.

Using your rear spoiler for down force is critical. You want to guide air off the roof and down the rear window with a smooth transition to the deck lid. Sometimes bodies have a sharp transition from the rear window to the deck lid area. If your rules allow you want to push up the deck lid to create a smooth transition to the rear window.

A smooth transition from the rear window to the deck lid area will reduce turbulence and allow the air to stick to the deck lid, flowing smoothly over the rear spoiler. Push the rear window up where it meets the deck lid as high as possible.

Fiberglass bodies allow for many options to create down force where you need it. You should consider your goals before mounting a new body. For example; if your car or track has a tendency to be tight (push) then you can help the problem by stacking the body to the front. Moving the body an inch forward is going to increase front down force significantly. If your car or track is consistently loose then setting the body back an inch is the way to go.

When mounting your body your goal is to have smooth and rounded transitions. If you can imagine airflow and think of air as wanting to stick to or follow your body lines. Sharp inside or outside body angles should be avoided at all costs as they create turbulence disrupting the air flow. Long rounded transitions allow the air to follow along the body and assists air in its natural tendency to follow surfaces.

During the next television Cup race pay attention to how the cars appear to track in comparison to the wall. You can visibly see how the bodies are mounted on an angle as compared to the centerline of the chassis. Engineers have discovered that they can pull the left front over and over hang the right rear quarter panel over the tire. Extending the RR out and keeping it in the wind creates down force on the RR which helps the car be more stable on corner entry. Skewing the RR quarter panel out keeps the spoiler in the wind on corner exit planting the RR for improved acceleration. Over hanging the body at the LF creates added down force on the tire that has the least load. With the front body panels offset to the left the car cuts better though out the turn. With a fiberglass body you can easily move your mounting points and mount your body on an angle for added speed.

Sealing the nose to the ground is paramount to making speed. Eliminating front lift and giving air the right start over the entire body equals more speed. This car has a "down force" body. If your rules allow, the wide panels and extra length are worth the investment.

The main reason a Big Bar Soft Set up works due to today’s bodies – they simply create way more down force than the vintage Camaro fiberglass bodies. If you go to a Sprint Car race on the dirt ask yourself which is faster; a winged Sprint car or a non winged Sprint car. On your late model your fiberglass body has significantly more surface area than a Sprint Car wing. Your assignment is to use the entire body to your advantage.. Sealing the nose piece to the track is the key to your Big Bar Soft Spring set up. Sealing the nose forces all of the air over the body. Any air that leaks under will cause lift and down force is lost. Making an adjustable valance will allow you to keep the nose down on the track with a combination of track conditions and car set ups.

An adjustable front valance will let you drop the nose right on the ground with a quick track adjustment. Getting the nose down for a perfect seal is a high-priority down-force item.

Your body should be a rigid structure at race speed. Any panels that are flapping are slowing you down. Flapping panels create unwanted turbulence and upset the airflow in an unpredictable fashion. If your front windshield and rear window deform in the wind you need to add supports until they are rock solid. Your rear spoiler needs to be solidly mounted and the use of several spoiler supports is a good idea. Fender supports should be used and attached at multiple points on the body to hold panels firmly in place.

If your hood deforms and flaps at speed not only are you losing down force but you are also diverting air away from the cowl intake potentially cutting critical air to the carburetor resulting in a loss of horsepower. Take the time to make sure your body panels are solid in the wind.

Using body braces to hold your body panels in place will give you a rigid foundation for maximum down force and air flow. This nose peice is clost to vertical at the sides. If you can, stretch the nose peice side panels out and let them angle back to the headlight which will make you more downforce.

The nose piece is a critical element. If your rules allow then pull the nose piece out at the front of the tires as far as possible. If allowed stretch the bottom of the nose piece out along the bottom edge. The idea is to create a sleek angle verses having a bulldozer at the leading edge. An angle from the top of the hood to the track equals down force. Even the sides of the nose piece can be stretched out. If the sides are perfectly vertical then you are leaving a few extra pounds of down force on the table. If the nose piece angles out from the headlight down to the bottom edge you create surface area for air to push down on and more speed is found. If your rules enforcement is soft then add a splitter to the lower lip of the nose piece which will add front down force.

The fender wells are another area where attention to detail pays off. You can trim the fender wells at the right side of the car to fit closely to the wheels. On the left you can keep the front edge close to the tire but you must provide ample clearance from the top of the tire extending around the fender opening to the ground. It is critical to leave an escape route for air that gets trapped under the hood. If there is not enough escape area to relieve the air pressure from under your car will see lift and could be unstable at speed.

Exchanging down force for drag on a short track is nearly always a good idea. That said – be sure to avoid any parachutes. Make sure the front side of the wheel wells extends to the outside more than the opening on the backside of the wheel well. Be sure the windshield posts are slightly outside the window posts at the quarter window.

If your rules allow, you can use your body braces for a few extra pounds of down force. As the tires spin at speed they create wind. Placing panels or body braces to catch the wind from spinning tires equals more down force. While small improvements add up for added down force a major gain is found if your rules allow a “down force” body. The extra wide panels and longer length are the source of valuable surface area. More surface area equals more down force. If your competition has a down force body and you have a template body it is truly and unfair advantage.

Finding extra down force is like removing weight from your car – you discover improvements a few pounds at a time. After discovering the big gain areas you can tackle the small areas. A few pounds of down force here and a few there can really add up. Make sure the leading edges of everything on the underside of your car are rounded. Allowing air to move freely under the car adds to the down force numbers. If you can make sure the rear bumper cover is rounded at the bottom edge to allow air out from behind the car.

Go Forward – Move Ahead
Jeff Butcher
Courtesy of JOES Racing Products
5/31/09
http://www.joesracing.com/

A-Arm Science

2009-06-05T09:33:00.000-07:00

Rolling through the center of the turn at maximum speed requires a suspension that is free of flex yet moves smoothly with out binding. A-arms have improved dramatically and choosing the correct A-arm will help you to create suspension systems that are faster and more consistent.

There are many things to consider when selecting the A-arm for your car. For dirt cars many racers have utilized arms that split at the bolt in ball joint allowing the a-arm to be opened for installations where the A-arm wraps around the frame mount. The split causes additional flex and high quality versions should be considered. The split A-arm utilizes a bolt in ball joint. Many top teams are switching to low friction screw in ball joints for better performance.

We built this fixture for this test which can apply from 0 to 1500 pounds of force right at the ball joint emulating the conditions seen on your car. We can also set up the fixture to cycle A-arms repeatedly for destructive testing.

Buying an A-arm shaft with simple drilled holes is a less expensive option yet using an A-arm with slots gives you repeatable adjustability. Successful teams keep an inventory of A-arm slugs on hand and pre-measure the caster at each increment in the shop. Pre-measuring lets teams experiment at the track with the confidence that the caster readings will be spot on. Utilizing the slugs creates a precision locating method helping to dial in the set up with quick caster changes right at the track.

Billet A-arm spacers help to maintain your settings when making changes at the track. These tapered shims keep your A-arm shaft straight preventing binds.

Machined A-arm spacers have replaced the days of caster camber washers falling all over the ground. A-arm spacers can be purchased in straight or tapered styles helping to keep A-arm shafts straight eliminating binding.

To further speed the job many teams use a A-arm nut plate that holds the backing nuts allowing use of one ratchet on the front side. Crew members appreciate avoiding the hot headers while holding an end wrench at an awkward angle.

Beyond choosing a slotted version or the basic single hole version, special attention should be paid to the tolerances between the steel A-arm and the shaft. The tolerance is critical as not enough clearance leads to binding and galling. Too much clearance creates unwanted movement and caster change especially under braking. At times excessive clearance can lead to chattering and an unstable car. In dirt applications too much clearance can allow dirt to crawl between the housing and the shaft and the grinding action causes premature wear, sticking and increased friction. Quality A-arm manufactures hold the tolerance for optimal performance.

4 Bearings spread out the load and this version has a machined bearing housing to keep the shaft in perfect alignment for lower friction.

As the suspension rolls and rides over bumps the A-arm is worked up and down continuously. For more consistent performance many teams are going to bearing style A-arms to eliminate friction. Teams are finding that with roller bearing A-arms that they can sometimes run slightly less spring rate due to the reduced friction. A-arms last longer as the bearings prevent the wear created by the steel A-arm tube contacting the shaft. Heat expansion from the headers and brakes can negatively affect standard A-arms if manufacturers do not use proper clearance. Bearing A-arms effectively eliminate the heat issue.

Bearing Style A-arms reduce friction for smooth roll and repeatable performance on the track. This version has a machined bearing housing allowing racers to replace just the steel tube section for quick adjustments or crash repair.

The smooth action of the bearings builds consistent suspension roll and increased corner speed is obtained over a long green flag run. The tight tolerance and low friction of bearing style A-arms eliminates variables allowing crew chiefs to make chassis adjustments with the assurance that the suspension is rolling up and down in a repeatable free flowing fashion. Removing the binding found in less expensive A-arms creates speed as the adjustment decisions are not chasing inconsistencies. Each crew chief decision becomes more effective and every racer should strive to eliminate variables for consistent speed week in and week out. Quality A-arms are powder coated for a premium finish where as less expensive models are spray painted which quickly wears off.

Adjusting the car with A-arm length can be very successful. Shorter RF A-arms create more camber gain and might help you to improve your tire sheet readings. Shortening the RF A-arm moves the front roll center up and to the right. At times the quicker reaction of the RF suspension, due to a shorter A-arm, can improve lap times. Experimenting at your track with A-arm length is just as effective as making a spring change. New A-arms on the market allow you to change the steel A-arm tube section while leaving the shaft bolted to the frame. These new designs speed trackside changes and reduce costs as racers can carry different A-arm tube sections without the added expense of extra shafts.

Big Bar Set Ups generally use longer A-arms than conventional set ups. Camber gain adjustments that line up with your Big Bar Set Up is a critical piece to the puzzle. At times teams jump between a conventional set up and a big bar set up. The A-arms with a bolt on section speeds the A-arm changes that are needed.

Utilizing low friction ball joints with your bearing style A-arm further enhances free movement of the front suspension. Some low friction upper ball joints are adjustable giving racers another adjustment. Fine tuning A-arm angle with the upper ball joint allows for quick roll center adjustments and easy experimentation. Adjustable upper ball joints can be used in conjunction with slotted frame A-Plates. Slotted A-plates allow the inner pivot of the A-arm to be moved up and down and slugs secure the inner pivot in place. The A-Plate slugs are manufactured for precision adjustment in the up/down axis offering another roll center tuning tool.

The weld on this A-arm is suspect. With out a proper weld bead flex and cracking can occur. High quality A-arms use thick wall .095 tubing and are TIG Welded.

Some A-arms flex more than most race teams think. Prominent teams test the flex of new A-arm brands before they end up on their car. Manufactures that use thick wall .095 tubing know the slightly more expensive tubing reduces flex as compared to .083 which is commonly used. TIG welding is another feature that will reduce flex. Poor quality wire feed welds make for limp noodles verses a rigid A-arm system. Be sure to inspect the weld quality before purchasing A-arms for your rocket.

Shaft type has an effect on flex. Choosing lightweight aluminum for the cross shaft comes at a price – aluminum flexes more than steel and racers should consider if the few ounces of saved weight in an aluminum cross shaft is a good trade. Our test results show that the steel shaft attached to a 9.5” A-arm flexes .110” at 600 pounds of force where as the aluminum shaft flexes .150” at the same force.

For this test we used our custom flex testing fixture applying force ranging from 200 lbs to 750 lbs. The dial indicator illustrates the flex difference between top brand A-arms and less expensive imitations.

A-ARM Flex Chart
.

9- ½” Bearing Steel Shaft No Name Brand

Flex at 200lbs = .060, at 400 lbs = .100”, at 600 lbs = .135”, at 750 lbs = .155”
.
9- ½” Bearing Steel Shaft Quality BrandFlex at 200lbs = .040, at 400 lbs = .075”, at 600 lbs = .110”, at 750 lbs = .130”

9- ½” Bearing Aluminum Shaft Quality Brand

Flex at 200lbs = .056, at 400 lbs = .105”, at 600 lbs = .160”, at 750 lbs = .200”
.

9- ½” Alum. Shaft (no slot) Quality Brand

Flex at 200lbs = .056, at 400 lbs = .105”, at 600 lbs = .160”, at 750 lbs = .200”

9- ½” Steel Shaft (no slot) Quality BrandFlex at 200lbs = .050, at 400 lbs = .075”, at 600 lbs = .110”, at 750 lbs = .130”

9- ½” Steel Shaft (no slot) No Name Brand
Flex at 200lbs = .090, at 400 lbs = .125”, at 600 lbs = .185”, at 750 lbs = .225”

Our fixture for this test was designed to apply varying pounds of force. The flex chart shows the movement associated with applying lateral pressure at the ball joint center line. The fixture is rigid and the frame mount is the same as you would see on your car. The goal in building the fixture was to emulate what your A-arms see in your racer.

Teams that reduce friction and flex will take another step forward. Racing continues to evolve and teams demand better pieces to find speed. Luckily manufactures are stepping up to the challenge.

Go Forward – Move Ahead

Jeff Butcher
Courtesy of JOES Racing Products
5/1/09
http://www.joesracing.com/

Rolling Resistance

2009-05-18T11:45:00.000-07:00

Finding speed a little at a time is the way to the front. A few horsepower here, less drag there coupled with a good shock change might add up to half a tenth on a good day. Reducing rolling resistance is one of those speed secrets that works continuously but it is hard to measure in the real world. Still – if your car has less rolling resistance common sense dictates that your race car will be faster.

Cup teams go to great lengths to measure improvements in rolling resistance. Several Cup crews have travelled to a hidden hill to test their ideas relating to reducing rolling resistance. The teams drag the car up to the top of a steep hill and set up to test roll the car down the steep grade to determine how far it will roll with out the help of the motor. They let gravity propel the car until it rolls to a complete stop. Teams test different roll resistance ideas celebrating the smallest improvement in free roll distance.

While your team may not be able to test rolling resistance on a secret hidden hill you can try some of the latest rolling resistance tricks. Running your hubs “wet” with low friction bearings and seals will reduce rolling resistance and increase car speed. You can really feel the difference based on the effort of pushing your car through the pit area. Oil filled hubs are the new rage and coupled with low friction seals you get many benefits. One spin of the hub with your hand is enough to illustrate the reduction in friction.

John Zaretske of JZ Motorsports likes to run oil filled hubs for improved speed. Low friction seals and bearings combined with 85/90 weight gear oil result in hubs that spin freely. John also likes the maintenance aspects of running oil filled hubs. Zaretske says: “Rebuilding and re-greasing standard bearings is an all night job – with oil filled hubs I can quickly drain the oil and inspect the fluid just like I inspect motor oil in a screened filter. Each week, if the hub oil is clean, clear and free from metal particles I just refill with 4 ounces of new fluid and I am ready to race”. John goes on to say: “in the rare event I need to replace my oil filled bearings, the job is much faster because I can just pour in the oil instead of making a time consuming mess packing bearings with old school grease”.

When running the hubs wet it is important to add the right amount of gear oil. 4 to 7 ounces is recommended by the car builers we surveyed and your team should monitor the fill level to ensure proper coating of your bearings. High quality synthetic lube is required.

You can experiment with the right amount of oil if you run your hubs wet. Zaretske recommends 4 ounces but other builders and hub manufactures may have their own recommendation. Our survey of car builders resulted in a recommended hub oil fill range from 4 ounces to 7 ounces utilizing synthetic fluid. As running hubs wet is a new speed secret you should keep an eye out as the fill level recommendations will change based on testing, fluid type and the evolution of manufactures specifications.

Weekly draining and refilling of "wet" hubs is simple. Fresh oil helps your parts and their longevity. Using a locking hub nut will ensure that your hub maintains torque even at lower torque settings.

Chuck Carruthers of Chuck Carruthers Industries says that only 5% of his customers are running hubs wet. Carruthers states: “Using Teflon coated bearings with 4.25 ounces of 50 weight synthetic gear oil gains 6 to 8 coast down horsepower”. Chuck prefers traditional wheel bearings and pays the extra cost for the Teflon coated version. Chuck feels the low friction roller ball style bearings are risky in long races. Carruthers says; “we get plenty of friction reduction from Teflon coated roller bearings and would rather avoid the added wear seen in roller ball bearings”. At Carruthers Industries they are careful and run the minimum amount of hub oil to ensure parts are coated but avoid running too much fluid as excess fluid in the hub can actually add heat. Chuck says “you want enough fluid to coat the bearings but any surplus fluid can foam or even impact how heat transfers and dissipates through the hub”.

Low friction roller bearings or Teflon coated tapered bearings will lower your rolling resistance where you need it most. Roller ball bearings should be inspected often and need continuous maintanance.

With the “wet” system and Teflon coated bearings Chuck recommends running 15 to 20 ft pounds of torque on the front hubs. He advises that you can run less on the rear as the brake heat is less intense. Chuck says 10 to 12 ft pounds on the rear hubs works great. Reduced preload on the bearings reduces rolling resistance creating more speed. Chuck reminds us “be sure to use a locking hub nut to ensure your torque setting stays put from cold to hot”.

We temporarily installed a clear cover to show the fluid level with 4.25 ounces of oil at 2 degrees of negative camber. A quick spin coats the bearings and races evenly.

Carruthers pays attention to detail and has made a special hub adapter for measuring hub torque. Chuck advises: “When our customers are doing their own work we have them torque the hub nut to our recommendations with a good foot pound torque wrench – we give them the setting and they simply torque down the hub nut and lock it down. For the cars that we maintain in our shop we go the extra mile and use a hub adapter that connects to a high quality inch pound torque wrench – the adapter connects to the torque wrench at the hub center. We add oil and give the hub a spin ensuring the hub and seals are lubricated. We then use our inch pound torque wrench with our custom made centering adaptor. We adjust the hub nut until we have 28 inch pounds of drag torque when rotating the hub with the torque adapter at cold temperature. When the hub is hot we know that there is minimal torque on the hub providing for optimal reduction in rolling resistance. At race temp we see about 3 to 4 inch pounds of drag torque with our custom measuring device”. Care should be used with this process as if the specs are not followed exactly you could end up with too little torque resulting in failures. Weekly inspections and pre-race checks are needed when pushing the edge in this fashion.

Rubber seals are the source of friction. You can easily feel the dramatic difference in spin effort from low friction seals as compared to traditional rubber seals. The added expense can be offset if your hubs have a seal retainer system.

While at the 2008 PRI show a confidential source explained the secret testing their team performed relating to floating rotors. Since my confidential source did not want to get fired by his team he wants his name kept out of this article. The secret tests performed by his high profile team revealed that running floating rotors added 6 horsepower on the chassis dyno. Making 6 horsepower due to brake efficiently – seems crazy! The HP gain is due to the floating rotors finding center through out the heat expansion range. The T-nut set up and rotor flange allows for a bit of movement that absorbs rotor warping and isolates it from the hub resulting in less brake pad drag. You get the horsepower gain and the brakes run cooler due to less pad and rotor contact. Drivers report smoother braking with reduced pulsing adding to the efficiency of the braking system. Here we go – a little more speed created by removing unwanted friction.

Using a floating rotor with a T-Nut package allows the rotor to expand through the heat range. The movement allowed by the rotor flange is isolated from the hub resulting in less drag. This hub has a seal retainer system that lets you remove and replace expensive low friction seals with out damage.

Another way to reduce rolling resistance is to square your rear end. There are many thoughts on rear end set ups but I like to keep this simple. I make sure my rear tires run nearly parallel and make sure the rear end is set square in the car. When building a rear end I make sure both tires point straight ahead and then I toe in the RR tire 1/32 of an inch. I figure at speed and under load that the RR will pull back that much and when it counts the rear end is perfectly square. A square rear end will not have any drag as compared to running toe out with the tires dragging all the way around the track. We know Cup teams play around with rear toe settings for aero advantages but for short track racing a square rear end will be more consistent and it will reduce your rolling resistance.

Equally important is the front toe setting. It is common for short track racers to run 1/8th inch or so of toe out and this spec has been around as the standard for a long time. I think the thought process is different now as compared to a few years ago. Today I recommend rethinking the toe out setting in the front end. Our components are simply manufactured better today and there is less free play in the front suspension pieces. A-arms are stronger, racks are better, rod ends, ball joints and tie rods are all built with tighter tolerances. I would recommend running 1/32nd of toe out or even zero toe out in the front. With the tires pointing straight ahead you can find more speed and eliminate tire drag from excessive toe out.

Ackerman should also be considered. Ackerman is sometimes used as a chassis adjustment but the Ackerman effect and additional degrees of steering at the left front tire creates drag. Keep in mind the amount of tire drag you are adding to the car if you have Ackerman toeing out the LF tire as you turn. Excessive Ackerman can sometimes cause a hitch when the driver picks up the throttle. As the power is applied to the rear tires they have to push against and overcome the Ackerman drag on the left front. Depending on the situation the car may break loose or simply not leap off the corner due to the Ackerman drag. Ackerman can be a great adjustment but thinking out the rolling resistance considerations may find you additional speed.

Aerodynamics is another area where rolling resistance gains can be found. Air likes to follow body surfaces and air needs smooth transitions to prevent unwanted turbulence. When ever possible create smooth and rounded body transitions verses letting air fall off of sharp corners or cliffs. When massaging air try to mold the body to allow air to follow surfaces avoiding surprise edges or cliffs.

As race cars have evolved reducing rolling resistance may help make up some of the power limitations created by crate motors, 9:1 compression motors, and carburetor rules. Embracing rolling resistance and massaging your car with a friction free approach may “find” you 15 to 20 new horsepower. If you are running a 400 horsepower crate motor you could end up with a net 5% improvement in power! Even with unlimited horsepower the teams that work hardest on reducing rolling resistance will create horsepower that just might be the nudge you need to get you ahead at the photo finish.

Go Forward – Move Ahead

Jeff Butcher
JOES Racing Products, Inc.
3/31/09
http://www.joesracing.com/

Shock Specialists

2009-03-17T10:24:00.000-07:00

Shocks are an important tuning tool that create feel in your car. With the variety of shock brands, components and types partnering up with a shock specialist can help you to navigate through the vast array of component offerings.

To increase our shock knowledge, we have interviewed two successful specialists in the shock field. Mike Naake of Naake Suspension Specialists and Mike Leary of Leary’s Shock Shop offer their suggestions and experience. Both “Mike’s” provide shock hardware, setups and technology to prominent racers across the country and are authorized service centers for many of the major shock brands.

With so many shock choices on the market how can you help racers choose the correct type?

Leary:
It is important to buy the most tunable shock within your track or organization’s rules. If your rules allow for compression and rebound adjustment the additional initial investment will translate into speed. If your rules dictate twin tube designs then the more economical hardware can be maximized through tuning. When rules allow we want our teams to utilize the options that are made available in pressurized mono tube shocks.

Naake:
Rules and budget are part of the equation. We tailor our shock packages to meet the needs of each racer. After a complete interview of each team we determine if pressurized mono tube shocks will work best or if the economics of twin tube shocks meet their needs. Once the shock type is selected we continue the interview to learn more about the goals of each team and build packages based on their input. Understanding driver tendencies and track characteristics allow us to tune shocks for more speed.

What is the racer benefit for partnering up with a shock specialist?

Naake:
Drivers and Crew Chiefs can communicate what they want the car to do and we can create an option based on the feedback. We can customize and offer a linear/digressive piston, digressive linear piston, double digressive piston, and another piston designed specifically for rough race tracks. Our knowledge is based on feedback from many teams and the information base gained over the entire group would be impossible to gain within a single team.

Leary:
With shock manufactures offering ever expanding part options for their shocks i.e.: pistons, shim stacks, shafts with different bleed options, etc, it is almost impossible for the racer to stay on top of his shock program. As shock specialists we are continuously being educated on latest product offerings from the shock companies we support. Racers also benefit from our experience – we are testing all the time and the knowledge gained by working with several teams helps us to understand the changes needed for each individual team. Our shock dyno runs full time creating unique shock packages even for teams competing at the same track.

What is a Mono tube shock?

Naake:
There are two types of late model/sprint car mono-tube shocks, emulsion and De Carbon style. An emulsion shock is typically a mono tube shock with gas and oil in the same chamber. The oil and gas mix creating foam. This is not a desirable situation in any hydrologic system, especially a racing shock absorber. Christian Bourcier de Carbon invented the mono-tube pressurized gas shock absorber. A De Carbon style shock absorber has a dividing piston that separates the nitrogen and oil. De Carbon mono tube shocks with gas pressure and a dividing piston perform better than twin tube shocks. Mono tube shocks cost more to manufacture yet the added expense results in better and more consistent performance.

Naake uses this photo to illustrate the base valve action on the mono tube compression stroke. As the shaft displaces the shock oil the base valve smoothly opens to allow for the shaft volume. Shim stacks can be seen flexing to meter the precise amount of shock oil.

The Naake mono tube rebound stroke photo illustrates shock oil flow and you can see the internal forces and valving action. The mono tube gas separating piston is clearly shown at the top of the shock.

What is a Twin tube shock?

Naake:
Many tracks and weekly racing series’ rules require a twin tube shock. They do this to keep the racers’ costs down. A twin tube shock has an inner tube that the piston runs in. At the bottom of the inner tube is a base valve. The function of the base-valve is to make 30%-40% of the compression force and replenish the oil in the inner tube on the rebound stroke. If a base valve is not performing with enough force in a twin tube shock that could result in cavitation or what we call in a twin tube design “dumping”. Dumping is when too much oil moves out of the inner tube too quickly and on the rebound stroke it is not replenished fast enough resulting in a momentary dead spot on the rebound stroke. The dumping can be verified on the rebound opening stroke of a constant velocity test on your shock dyno.

Naake uses this photo to show the low pressure gas filled bags utilized in twin tube shocks. The low pressure bags prevent foaming and deform to account for shaft displacement. The Base Valve adds 30 to 40% of the compression force.
Naake points out twin tube shocks have an inner tube that the piston runs in. The twin tube rebound view shows the base valve metering oil from the outer oil reservoir.

Why run a base valve?

Leary:
Base valves are of most benefit on heavy cars and when low gas pressure is used. For most late models we run without base valves in mono tube shocks to save cost. As you run high compression it can make sense to add a base valve to help prevent cavitation on the back side of the piston. When running a base valve the shock valving needs to be tuned to line up with the compression forces that are metered through the base valve.

Naake:
A base valve is an optional component on a mono tube shock and works great with low pressure. Some series that allow mono tube shocks do not allow base valve to be installed. A base valve shock will have a much smoother feel to the driver than a non-base valve shock. Of course, a base valve in a shock adds to the cost. We are big fans of base valves when rules allow. The added control of the oil displaced by the shaft gives us more choices with our rebound adjustments as cavitation is eliminated through transition from compression to rebound.

Is shock oil important?

Leary & Naake:
Shock oil is a part of the shock that most racers overlook. Many manufactures use inexpensive hydraulic oil in their shocks. Inexpensive oil can vary through out the temperature range. You may start the race with a shock that has a 5 valving on compression and rebound. Inexpensive oil may react dramatically with heat and effectively make the 5 shock you built in the shop perform like a 3 shock on the track. Using thin synthetic oil reduces the viscosity change allowing for more consistent shock performance from ambient temperature to race temp.

Using a drip cup for shock rebuilding keeps the oil contained and your workplace clean. An organized shock building station is a must if you are servicing shocks on your own.

Leary tested several 5 shocks from different companies. This graph shows that a 5 shock valving varies significantly from brand to brand. Understanding the brand valving differences will help you to make the proper adjustments when using competing brands.

What Shock tips can you give to our readers?

Naake:
We hear a common myth that bag shocks blow out due to rough track conditions or sudden high velocity compression. In my experience, I just do not see this at all. The only bag failures I have seen are due to errors in assembly or a bag had a small puncture prior to assembly.

You can perform a simple hand test of your twin tube style shock. Fully extend the shock. Position the shock so that the shaft end is up. Compress the shock about a half an inch. If you feel any slack or a dead spot, it is an indication of air in the system. This can be caused by the shock being low on oil, either from the shock having an oil leak or from not enough oil placed in the shock during assembly. It could also indicate a leaking gas bag. We perform this test on all twin tube shock prior to running a dyno test. If they don’t pass the hand test, they are guaranteed to fail the dyno test.

Leary:
You should have your shocks dyno’d when they are new to get a baseline, and then should be re-dyno’d after a crash and halfway thru the season. A shaft bent 3 or 4 thousandths or a tiny dent in a mono tube shock body, will change the shock dramatically. In this day in age, it is almost impossible to build your own shocks without testing them on a quality dyno. Using the proper tools such as, shock wrench, shock vice and drip cup will make the building process easier and protect your investment. Keeping your shock work area clean and organized is pivotal to building successful shocks.

If you are going to work on your own shocks then using the proper tools such as a shock vice will help you to build winning shocks.

What shock adjustment tips can you suggest?

Leary:
Most of the handling of a pavement car is controlled in the first 2 inches of shock movement. I like to use the rear shocks to control the entry of the corner, left side shocks and RF for the middle of the corner and the fronts for exit.

I avoid using the compression side of the shock for handling adjustment. I would rather use springs to control compression adjustments. The one exception is possibly the compression on the left rear – by increasing the compression at certain speeds, you can gain bite off the corner. It can make the car think is has more LR spring on exit without changing the corner entry like a spring can.

On a conventional spring setup, the shock settings will work differently than with a soft spring set-up. The more front spring rate, the less compression you need because the spring is doing the work. With a soft front spring set up, you need to use compression to control the speed of the front end movement because you have a 200 lb spring trying to hold up an 800 lb corner.

If you tie down the left rear shock on a conventional set-up, I’ve found you will tighten up the entry of the corner. I believe it keeps the left rear weight from transferring to the RR as fast, which gives you that loose entry feeling and keeps the weight on the LR tire.

With a soft spring set-up, if you tied down the LR, it usually will loosen the corner entry. Because of the rapid weight transfer to the RF of the car, we can overload the RF tire, which can cause a soft push on entry. By delaying that transfer the RF tire has a chance to “grip” the track, so the driver feels the car is looser on entry.

With either conventional or the soft spring set up, the rebound on the RF can help that “tight in the middle” feeling. By stiffening the rebound on the RF it holds weight on that tire and helps it maintain grip – it also keeps the RF from transferring weight to the LR as fast, which will cause the car to pick up a push. The downside of holding down the RF is you can lose some grip off the corner, because you are delaying that weight transfer to the LR.

When we have soft front springs, we need the rebound on the LF shock to help the sway bar to keep all that weight transfer to the RF. That is why we see the extreme tie-down LF shocks. It is important to balance your front springs/sway bar and tie-down in the LR shock. We build LF shocks at 1 inch of travel anywhere from 600 lbs of force to 1000 lbs, depending on the set up.

Changing the sweeps on externally adjustable shocks makes a big change. Leary uses this dyno graph to illustrate the dramatic effect of using sweep adjustments.

Naake:
To help free up the car from the center off a quick adjustment is to add gas pressure to the RR shock. By adding up to 200lbs (if you have the right hardware) the car can take on a better attitude and become more stable on exit. This fix is quick and can be removed quickly if the driver is still looking for a better exit.

With today’s set ups we like to maintain rebound in the front shocks. If the car is tight, and if the team has the right hardware, we try to go with high frequency pistons to relieve the tight feeling. In short, there is an o-ring behind the shaft band that delays the metering of oil through the bleed holes for a brief moment and then shuts the bleeds off just as quickly. Our teams can work with us to discuss these options to find more speed – our goal here is to let your readers know that there is high tech hardware out there that goes beyond generic answers. We have proven results in gaining front grip off the corner with the high frequency hardware available. Remote canisters provide another layer of adjustability when allowed.

While high tech is cool sometimes a basic answer works well. If your car is tight then more compression in the RR will help the car turn in the center. You can try a bit more rebound in the LR to free it up. You can take a little compression out of the LF or tie down the RF to help the car turn. Extreme rebound in the front shocks is good in many cases but too much low speed control can reduce front grip. With extreme front rebound you need some bleed to allow the tire to follow the track surface.
When rules allow a remote shock canister gives you more compression adjustability options. Base valves can be built into remote reservoirs and the housing needs to be protected from damage. Using a canister mount allows for quick adjustments when practice time runs short.

Summary:

Butcher:
Shock science and hardware is constantly changing and the application of the set up tips is very dependant on the track, driver and location in the turn. Many times a standard shock tip will change 180 degrees based on moving the car a few feet in the corner and the tips above need to be applied with full understanding of shock mechanics – both Mike’s will change their adjustments based on real world data. When it comes to shocks it is all about timing and transitions. Shocks might hold or delay movements but in the end the springs carry the load. Bumps, braking, throttle and rolling through the middle all provide information that will be analyzed independently by your shock guru. Be aware that you may have soft front springs but you also must consider the overall front spring rate based on the giant sway bar that could be in your car.

Go Forward – Move Ahead

Jeff Butcher
Courtesy of JOES Racing Products
www.joesracing.com

Resources:

425.267.9199

916.771.0109

Tires & Temperature

2009-01-26T12:13:00.000-08:00

You spend piles of time figuring out how to make more horsepower, optimizing shocks and building lighter cars which all come together where the rubber meets the road. Every speed secret on your car is applied at the contact patch so creating the optimal footprint is the meeting place for all of your hard work. Tires are the single most important aspect of speed as every adjustment from motors to springs relies on the grip you manufacture at the contact patch.

Measuring tire temperatures accurately will provide the information you need to produce even grip and maximum friction where it matters most. Using pyrometers correctly provides valuable information. Often, a tire sheet is handed to the crew chief and the numbers on the paper sets in motion a flurry of adjustments. The thrash begins and springs fly. Orders are barked and the crew moves quickly to get the car back on the track with hopeful anticipation of new found speed. Temps are taken to see how the new adjustments worked out and too often the intended chassis improvements are 180 from what is needed. The driver reports the car is even worse than before the recent round of adjustments. Did the missed set up attempt occur due to a poor choice on the chassis adjustment? Or - were the wrong changes made due to poorly measured numbers on the original tire temp sheet?

It is worth noting that tire temps and pyrometers are one of the few ways that you can analyze real time data right at the track. If the temperature measurements are taken correctly, chassis specialists can calculate the best changes that will perform for the length of the run. Using up important practice time and valuable practice tires with wrong way adjustments is expensive. Choosing the correct pyrometer to produce scientific information and assigning the crew member that is dedicated to precision is paramount.

To dissipate heat racing tires are very thin. Thick tire rubber holds in heat and the potential for blistering increases. Tire engineers balance the rubber thickness with tire compounds to produce a package that considers car weight, corner speed, track abrasiveness, outside temperature, intended lap use and several other variables. Since the thickness of tire rubber can vary you need a pyrometer with an adjustable tip length probe. We want consistency and measuring tire temperature down at the cord is the best way to ensure accurate and repeatable numbers. If your team is measuring tire temps at varying depths then the information on the tire sheet is going to set in motion changes that could slow your car down.

Pyrometers must be used constantly - scientifically. Rubber is a poor conductor of heat yet it is a great insulator. If you are trying to assess camber temperature curves then you want to know the inside, middle and outside temps based on your camber setting and corner performance. If you measure the inside location at the rubber surface, the middle location and mid tread depth and the outside at the cord your temp sheet is going to have more inconsistency than Michael Jackson has had cosmetic procedures. The cord heat is insulated away from the outside elements and the most heat will be found beneath the rubber and down at the cord. Scientifically – it makes sense to measure all 12 locations at cord depth where the purest temperature is located.

Adjust your pyrometer probe so that the adjuster stops the probe penetration just before the probe reaches the tire cord. Using the stop on the adjustable tip will allow your crew to quickly and consistently get down to a consistent depth near the cord each and every time. Your temp sheet will provide scientific quality information due to the repeatable and consistent probe depth.

Reading rubber temperature down at the cord is best as the friction of your tire pulls and stretches the tire rubber. The stretching effect creates heat just like when you bend a coat hanger back and forth. More friction creates more contact rubber stretch. Measuring down near the cord displays the data resulting in efficient chassis adjustments.

If you have a pyrometer with a fixed tip you can make it work but you introduce depth variables. How many times have you seen a temp sheet that showed you needed to take out RF camber and sent the car back out without an adjustment. A second temp reading shows you have too much camber – I will bet probe depth variation is the issue. With a fixed tip your crew needs to “feel” the cord to ensure the probe is at a repeatable and consistent depth.

Your probe tip is made of thin steel which heats up quickly sucking the heat out of the pin hole made in the tire rubber. Be sure to move quickly. If you leave the probe in one spot in the tire rubber and watch the display you will see the temp rise and then begin to fall as the heat is sucked out of the test location. You need to record the maximum temp in each probe location. High quality pyrometers lock in the maximum temperature automatically increasing accuracy. Utilizing a temp lock feature gets you around the car in nearly half the time.

I am often asked if Infra Red pyrometers are good for tires. You certainly can use Infra Red pyrometers for tires but it is a quick check and the information is simply less precise than using an adjustable tip probe. IR pyrometers measure the tire surface. The surface temperature is impacted by engine heat, brake heat, puddles etc. Camber in the front tires places only a few inches of the tire on the ground at the low speeds encountered when travelling back to the pit area. The track surface is cooler than tire operating temps so the tire surface area in contact with the ground pull heat from the strip in contact with the track at a different rate than the rest of the tire – this difference skews your camber curve readings. The rubber down at the cord is insulated for a longer period giving you more time to measure temps relative to on track performance and probes can reach down past the surface for a better look.

When using IR pyrometers for tire temps bear in mind that the surface recordings will be much cooler in comparison to probes and you will lose the fine detail that can be found with probe type pyrometers. IR pyrometers are great tools for measuring track, header, brake and cockpit temps. Using the right tool for the job is usually sound advice.

To ensure the best relative tire temp readings follow these steps:

1. Use a properly adjusted pyrometer probe tip to measure down at the cord.
2. Get to the car quickly – speed matters!
3. Record the highest temp at each location with an automatic max temp feature or by manually witnessing the highest temperature. Move around the car quickly.
4. Start at the same tire each and every time and record the individual Inside, Middle and Outside for all 4 tires. Consistency is the goal.
5. Record track temp and outside air temperature on your tire sheet to monitor the difference that these variables have on your tire temps – over time you will be able to forecast better compensating adjustments.
6. Keep in mind that tire temps are of more value on a car that is handling well and with tires that are in good shape. Tire temps on cars that are in left field are about as valuable as politicians’ promises.

Using your scientific tire temps you can evolve my rule of thumb tips shown below. My tips are based on a car that is set up properly and just needs fine tuning. Your team should adjust the suggestions below based on your real world testing and document your own pre-determined adjustment to form your own game plan. Creating a game plan in advance will allow you to quickly asses your adjustment options improving your decision making when things get hectic at the track.

Camber Adjustments.
Your tire sheet temperatures suggest a camber adjustment is needed but knowing the adjustment amount is an educated guess. My rule of thumb for adjusting camber is a 1/8” shim for 12 degrees of temp difference between the inside and the outside. A 1/16th shim is a good start for 6 degrees difference. Trial and error starts somewhere and your team can modify my rule of thumb based on your actual conditions. Strive to find and document a pre-determined shim thickness associated with the degree difference across the tires on your car.

Starting Cold Air Pressure.
Air pressure and tire temperature work hand in hand. If you take precision tire temp measurements you can gain an advantage over the competition by adjusting your cold air pressures before the race based on data you have collected over time. You can adjust your pre-race air pressures to a finer degree if you record outside and track surface temps in conjunction with your tire temperatures. If it is really hot out and you have tire temps that are 20 degrees higher than your last trip to a given track you can adjust the cold temps for better race performance. The rule of thumb that I used on a 2900 pound touring late model with bias ply tires was 1 degree of pressure gain for every 10 degrees of additional tire heat. You can visualize that there would be more pressure gain in the heat of summer verses a cool spring. Testing dictates your actual heat induced air pressure compensations. Adjusting your pressures based on recorded results will help you to optimize pressures for more speed on a long green flag run. Understanding the correlation between pressure and temperature will help you to optimize pre-race pressures during those times when your race set has residual temperature from practice and the race is going to start before the tires cool completely. Strive to know the actual temperature induced pressure gain based on your driver, track and conditions.

Air pressure adjustments.
Inflating each individual tire properly means better grip, more wear and more speed. With accurate tire temps my rule of thumb is to adjust individual pressures 1 pound for every 5 degrees of over or under inflation shown as hot or cold center temps on my temp sheet. Your team can tailor the starting point of this rule of thumb to your actual situation. Your team may decide on 1 pound per 4 degrees or something different but the goal is to find the pressure needs for your car and tires. Establishing a baseline for inflation pressure adjustments will help you to dial in the winning set up and add consistency to your set up process.

Measure and record your tire temps with a quality pyrometer. Use the scientific data to form a pre-race game plan. Use your game plan to make the right call when it matters most. By using science you can take the black magic mystery out of your tires by building consistency in your adjustment process.

Go Forward – Move Ahead.

Jeff Butcher

Tools Courtesy of JOES Racing Products, Inc www.joesracing.com

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Camber and the Tire Contact Patch

2009-01-26T10:40:00.000-08:00

Drivers like cars that cut into the turn. Optimizing your camber and understanding the tire contact patch will make for a faster car that stays fast through out the race. With today’s highly engineered tires, bump stop set ups and high level competition adjusting camber for maximum grip will help you win.

Camber is simply the tilt of the tire. Standing in front of the car if the top of either of the tires tilts towards the engine it is negative camber – if the top of the tire tilts away from the engine it is positive camber. To measure camber a quality all billet camber gauge will have the perfect surfaces to provide accurate and repeatable readings.

A billet caster camber gauge has the machined surfaces for accurate readings.

Camber is essential to match the contact patch to the bank of the turn balanced against your Upper A-Arm and Lower Control Arm lengths. Even if the corner were flat we would want camber. We need camber to work with the Upper and Lower Control Arms to achieve proper camber gain through suspension travel. Camber coupled with gain will optimize the tire contact patch taking advantage of the tire construction parameters.

Think about the changing camber angles in your race car through travel. We adjust the suspension and camber to achieve reasonably even tire wear producing tire temperatures that are balanced. That said, what we really want is the entire foot print of the tire on the ground under full corner load by using correct camber to match the spring load of the inner and outer sidewall. Too much camber loads the inside side wall too much and not enough camber loads the outside sidewall too much. If you want your car to cut through the center of the turn then it would make sense to have all of the available rubber firmly in contact with the ground.

Tire Contact Patch Explained

For this tire contact patch exercise think of a trampoline – we are going to compare a trampoline to how a race tire works. Imagine a trampoline to create a mental illustration of how the tire contact patch is stretched. Think of the trampoline outer frame as the tire bead. Now think of the tire side wall as the trampoline springs. Compare the trampoline surface to the tire rubber contact patch and visualize how tightly and evenly the trampoline surface is stretched by springs towards the frame. Our goal is to have the tire contact patch stretch evenly and tightly just like the trampoline surface. The tire bead is very rigid and creates a sturdy frame. The side wall of the tire is a spring that absorbs loads. By using camber to maximize the power of the sidewall springs the contact patch stretches flat and stays in full contact with the ground producing more grip.

The ideal amount of camber is achieved when the inside sidewall sets into the track to provide maximum pull at the tire contact surface. The stretch pulls evenly from the inside sidewall to the outside sidewall. The correct camber setting will utilize the entire contact patch. If you have too much camber the inside of the tire will not have enough initial surface area to pull the contact patch across and the spring of the outer sidewall will not be engaged. Not enough camber and the contact patch will deform and ball up at the inside edge – the contact patch rolls up and off the ground as the inner side wall spring needs more loading.

We use pyrometers to measure the tires on the inside, middle and outside. When the pyrometer shows a hot temp on the outside of the RF we add camber. Too hot on the inside RF and we take camber out. There is an exception that goes against the common thought of taking out camber when the pyrometer shows a hot reading on the inside. When would you add camber even though it opposes the pyrometer readings? Understanding the tire contact patch will help you set the camber through the exception.

With your trampoline comparison at the front of mind visualize the RF tire surface as it rolls through the turn. Think about the part of the turn where cars choose to cut or push. At this full tire load point, if you do not have enough camber, the contact foot print will not be stretched tightly between the two sidewalls (like in our trampoline comparison) and the pyrometer will show excessive heating on the inside of the tire and the exception occurs. In this condition we add camber even with higher inside RF temps. The excessive heating on the inside generally indicates to take camber out – thinking outside of the numbers may be in opposition to typical camber adjustments.

This exagerated view of a contact patch buldge illustrates how too little camber can show a hot reading on the inside. Understanding the contact patch will help you to make the right adjustment.

You may indeed need to take out camber of the RF due to the excessive inside readings but before you do inspect the tire and look for the exception. Look for rolling at the outside edge. If you see scuff marks extending to the outside sidewall this is clue one. If the outside edge looks rounded this is clue two. Now the important clue – closely inspect the inside of the RF tire about 1” inch from the inside edge. Look for a strange wear area that is about ½” wide that looks different than the surrounding rubber. It will look grainy, be cupped or perhaps mimic wind blown sand on the desert. Remember – it is more effective to dial in camber with new tires. Worn tires may have been misused and can provide false readings. Added attention should be paid to tire temps when you bolt on a new set and high quality pyrometers should always be used. Tire Temps make the most sense when the car is close. Feedback from temps can be erratic if the car is way off.

Exception Explained

If you do not have enough RF camber inside sidewall will be under loaded. The outside sidewall gives way and folds in deforming the contact patch. The deformed tire footprint pulls up off the track surface – as the deformed contact patch reaches the inner sidewall it is forced back down creating a protruding bulge as it curves back to the inner sidewall. Remember the trampoline comparison, we need the contact patch stretched evenly from the sturdy outside bead, through the outside sidewall spring, tightly across the contact patch, through the inner sidewall to the firm inner bead. In this exception adding camber at the RF will load the inside tire wall with the ability to firmly hold the inner edge of the tire foot print. The rolling or protruding of rubber at the inside edge is due to inadequate static RF camber. Don’t be fooled by this short term and artificial temperature. The extra temperature is created from the deformed contact patch bulge as it curves back to the inner sidewall. The bulge rubber will quickly grind off permanently damaging the tire. and the true pyrometer reading will show up! Proper camber will give the inside of the tire the maximum grip allowing the contact patch to stretch trampoline tight all the way across. Proper camber will allow the outside side wall to be pulled in by the contact patch rubber connecting the inner and outer sidewalls in unison and with equal load.

Camber - Old School

Camber gain through travel is related to your static camber, your Upper A-Arm and Lower Control Arm lengths. Consider the amount of travel your front end experiences. If you have an old school set up verses a Bump Stop Set Up there is less overall travel and the Upper A-Arm will be short. With Bump Stop Set Ups there is more travel from your static ride height and much longer Upper A-Arms slow camber gain.

For a pavement touring late model old school thinking was about 1 degree of camber gain per inch of travel. This guideline was a rough starting point with traditional set up and would be adjusted as needed to actual conditions. With a 17 ¾” RF Lower Control Arm a typical Upper A-Arm would range from 7 to 8.5” +/-. The increased angle of the Upper A-Arm provided for camber gain from static to maximum load. With standard suspension travel and a static camber of 3.5 degrees negative you would achieve about 5 to 6 degrees of camber in the center of the turn. Gain would be 1.5 to 2.5 degrees of camber through travel. Every car and track is different and these ball parks give are a simple view of old school camber

Camber - Bump Stop Set Ups

Bump Stop Set Ups require Upper A-Arms to be considered in an entirely different way. Longer Upper A-Arms slow down camber gain so it is wise to measure your camber with the car on the bump stops emulating the center of the turn. Static ride height is of zero value on a Bump Stop Set Up – as soon as you reach race speed the car is down on the stops and never sees static height again until you load it back in the trailer. Since shocks with mammoth amounts of rebound hold the car down on the bump stops the ride height static camber is not even worth checking. Bump Stop Set Ups use much longer Upper A-Arms, such as 8” to 12”, yet the Lower RF Control Arm is still around 17 ¾ on a touring late model.

When using bump stops be sure to consider your A -arm lenghts and angles.

The Goal

Your goal in identifying the proper camber is to find the optimal camber amount that creates maximum tension across the tire surface by equally loading the inner and outer sidewall. Dialing in the camber for the conditions will help the car turn. Too much RF camber and the inside edge will not hold – not enough and you will get balling up at the inside edge.

To set camber with your Bump Stop Set Up I would pick a repeatable ride height down on the stops that represents your best estimation of ride height in the center of the turn. A repeatable middle of the corner ride height number will make a better week to week reference point then trying to chase a ride height that varies based on how you adjust the shock body etc. For a Bump Stop Set Up I would start with 4.5 degrees of negative camber at the RF at my mid corner reference point and would not even care about static ride height camber. I would dial in the optimal camber with my pyrometer and tire inspections. I would look for consistent tire temps on short runs with new tires and longer runs with the same new tires. Adding or subtracting from my initial set up would be based on the feedback the car provides. The left front starting setting would be 3 degrees positive with the car on the stops and I would experiment there.

Tire Temp Tip

From experience my fastest cars had RF inside temps that were 10 to 14 degrees hotter than outside temps. The small amount of extra inside heat ensured that I was just reaching over the edge giving me the best shot at a fully stretched contact patch. I made sure to verify the temps on both short and long runs with new tires. The LF has less load so 12 to 16 degrees hot on the outside temp showed me LF outside tire wall was digging in with everything it had.

Go Forward – Move Ahead.

Jeff Butcher
Courtesy of JOES Racing Products

Bump Steer & Bump Stops

2009-01-23T14:07:00.000-08:00

Under maximum corner load, where races are won, excessive Bump Steer can slow your car down and make it more difficult to find the optimal set up. Understanding Bump Steer will increase corner speed and give you more options in finding the winning set up.

What is Bump Steer? Bump steer is the toe in and toe out of your front wheels created by the up and down movement of your suspension. Really – bumps aren’t even needed! When the nose lifts under acceleration do you want the wheels to turn in or out on their own? What about when you are under heavy braking? Do you need the Right Front wheel to go one way and the left the other? Think about when the car transitions between compression and extension – we want the driver to steer and not have to correct for the inconsistencies caused by improper front end settings. When the suspension oscillates over bumps the last thing we want is to have the tires turn themselves due to excessive Bump Steer.

Bump Steer is caused when the swing arc of the suspension is not matched to the swing arc of the tie rod. Different swing arcs of the tie rod and suspension are what causes Bump Steer. To match the arcs you must follow a few simple design principles that were considered by your car builder.

Stock car suspensions are comprised of an Upper A-arm and a Lower Control Arm. Your frame sets the inner pivots and your spindle and ball joints set the outer pivots. Your car builder thought long and hard about all of layout dynamics to engineer the hardware that allows you to properly position components to attain Zero Bump Steer (Fig 1).

(Fig 1). Your car builder carefully engineered the pivot points, angles and lengths. Setting the Bump Steer is like Blue Printing the suspension to exactly match the design specifications.

The layout, lengths, and angles of the upper A-Arm work together with Lower Control Arm to encompass what engineers refer to as an Instant Center. To help understand the Instant Center you can visualize a triangle (Fig. 2). Draw a line from the center pivot of the top ball joint down to the center pivot of the lower ball joint. Now draw a line from the center of the top ball joint through the inner A-Arm pivot and extend it towards the middle of the car. Complete the triangle by drawing a line from the center of the lower ball joint through the inner pivot of the Lower Control Arm and extend it to the spot where it meets the Upper A-Arm line. The intersect point of the two lines is the Instant Center of your suspension. The RF and LF have independent Instant Centers.
(Fig.2) Your pivot points work together and intersect at the Instant Center. The illustration shows the RF suspension from the front view.

With your triangle drawing (Fig 2.) you can imagine a very long tie rod – one so long it would not fit on a late model as we know it. Connect your imaginary long tie rod with a mental bolt at the Instant Center. Extend your imaginary tie rod out towards the spindle and connect it to the center of the line between the upper and lower ball joint. With this layout you can see that the imaginary tie rod would follow the same arc through travel as the suspension (upper and lower control arms) and the car would achieve zero Bump Steer.

Matching the arc of your actual suspension to the arc of the tie rod completes a design scenario that points your tires straight ahead through suspension movement. To apply the matching arc concept to the design of your late model you will need to consider three design principles for ZERO BUMP.

Your outer tie rod pivot must fall on a line drawn through the upper and lower ball joints.
Your inner tie rod pivot must fall on a line that is drawn through the Upper A-Arm pivot and Lower Control Arm pivot.
The angle of the tie rod must create a line that when extended intersects with the Instant Center.

Race cars are made from welded steel that bows and twists from the heat of welding. Rack plates, steering box mounts and spindles all can have variations that we need to account for by utilizing shims to locate the pivots considering our 1-2-3 design elements. Setting the Bump Steer is like blue printing an engine – you are simply going the extra mile to match your car exactly to the car builder design specifications (Fig 3.).

(Fig 3.) Typically Stock Car tie rods follow the Lower Control Arm line. In our drawing we are illustrating that you can mount the tie rod elsewhere as long as the outer tie rod end falls on the Ball Joint Axis line, the inner tie rod end falls on the Upper A-arm and Lower Control Arm pivot line – and the angle of the tie rod ends intersect with the Instant Center.

Often rack plates are mounted too low for direct mounting of the rack. To achieve the proper pivot points detailed in our 1-2-3 instructions we may need to space the rack up (Fig 4). Using CNC machined billet rack spacers adds to the precision or simple washers can be used if you have the correct thickness on hand. Shims may also be needed on the spindle side to account for caster changes or spindle variations.

(Fig. 4) Mounting the rack at the proper height allows for zero Bump Steer.

To measure the Bump Steer you need a precision Bump Steer gauge and you will find a digital version speeds up the project. Suspension settings need to be racing ready and the proper components need to be fully installed and tightened. All front end settings need to be set – exactly. Tackling the Bump Steer measuring process should only begin when the car is truly race ready. Prepare your car in the following order and consult your car builder for their recommended front end specs. Make sure you have the right parts on your car!

(Fig. 5) A Precision Bump Steer Gauge that is billet rigid and utilizes one dial indicator will do the math for you for a faster and more accurate Bump Steer process.

Prepare the car to measure your Bump Steer per the following Check list:

1. Set the tires – air pressures and stagger.
2. Set the ride height.
3. Adjust the camber.
4. Adjust the caster.
5. Match your tie rod lengths per the1-2-3 instructions.
6. Center the steering by centering the inner tie rod ends with the Lower Control Arm inner pivot per the 1-2-3 instructions. Lock the steering in place to ensure solid measurements.
7. Set the toe.
8. Record a reference point while your car is on the ground and at your design ride height. Measure from the floor to the lower grease fitting or other repeatable spot such as the sway bar mount on the lower control arm – remember to write the number down.
9. Place the car on jack stands matching your ride heights and adjust for the jack stand height. The goal is to maintain your suspension angles while on jack stands matching the ride height on the ground.
10. Bolt on the Bump Steer plate to the hub and set it to level. Jack the suspension to ride height and note where the dial indicator touches the Bump Steer plate. Setting Bump Steer is a trial and error process and noting where the dial indicator touches the Bump Steer plate indicator marks will allow you to return to your ride height quickly after attempted adjustments.
11. Jack the suspension fully through compression with bump stop set ups (or at least 2”) and through at least 2” of rebound travel. Write down your results and refer to the Quick Shim Guide (Fig. 6).
12. Shim as needed.

To help you shim your way to proper Bump Steer here is a Quick Shim Guide that you can use after taking an initial Bump Steer measurement (Fig 6):

Quick Shim Guide

Toe out in compression & toe in on extension.
Reduce shim thickness at spindle or lower the inner tie rod end by lowering the rack or drag link.

Toe in on compression & toe out on extension.
Add shim thickness at spindle or raise the inner tie rod end by raising the rack or drag link.

Toe in on both compression & extension.
Lengthen the tie rod.

Toe out on both compression & extension.
Shorten the tie rod.

Toe out on compression. Toe in on extension and then toes out with additional extension.
Reduce shim at spindle and shorten tie rod.

Toe in on compression. Toe out on extension and then toes in with additional extension.
Add shim at spindle and lengthen tie rod.

Bump Steer is stated as X amount of Bump Steer (in or out) in 1” of travel. The starting point for measuring Bump Steer is your static ride height. In today’s world of bump stop set ups the reward for zero Bump Steer is even greater. Bump stop set ups allow for more travel – in fact bump stop set ups use all of the travel! More travel multiplies Bump Steer geometry errors and spending the time to get it right does mean more speed and more importantly it produces a fast car all the way to the end. Why fade when you can win? Is improper Bump Steer one of the reasons why some cars slow down at the end of races?

If you have excessive Bump Steer you are un-necessarily heating your tires and wearing them out. The tires go over the bumps in a very fast manner and those millions of in and out toe oscillations generated by too much Bump Steer produces un-wanted tire heat and instability. You can think of it nearly as a toe vibration – in and out – back and forth in rapid motion. Remember, the movements occur through travel not just from bumps. Braking, acceleration, roll, transition all create movements that will magnify Bump Steer. Get rid of Bump Steer and let the driver turn the wheels verses letting the tires turn unpredictably on their own!

So – now that we see the Bump Steer light it is time for the golden question. How much Bump Steer should we run? It’s a matter of opinion and every set up guy has their magic formula. My answer is as close to zero as possible. What ever Bump Steer amount you use should be a recorded and repeatable number that is adjusted verses being an accident. Repeatability in race set up is the way to go.

A small amount of Bump Out is stable. Bump In can cause an unstable car – I always stay away from Bump In. A small amount of Bump Out ensures that my cars avoid Bumping In. A small amount of Bump Out ensures that you avoid Bump In through component flex and it covers unforeseen variations. With Bump Stop Set Ups and Big Bar Soft Spring Set Ups my recommended number is .004 of Bump Out per 1” of travel both left and right.

Before Bump Stop set ups - utilizing a common set up in a 2900 pound touring late model my base Bump Steer set up was .002 to .005 of Bump Out on the RF and .005 to .008 of Bump Out on the LF. Consult your car builder and use his experience. Remember, every car builder has their own idea of Bump Steer settings. Consistency and repeatability are the goal.

“A qualifying trick is to bolt in an extra .187 shim on the LF for your qualifying run which adds about .010 of additional Bump Steer at the LF for a qualifying total of .018 verses my standard .008. Sticker tires and their extra short term grip cover the negative effects of the added Bump for a lap or two. The benefit of the extra Bump Steer is that it manufactures some quick heat in the LF. Under the stress of a one or two lap banzai run the added LF quick heat helps set the car into the middle of the turn - sticker tires make it work”.

Go forward – move ahead.

Jeff Butcher

Tools Courtesy of JOES Racing Products, Inc. www.joesracing.com