Just Breathe

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

8/01/10

Make or Brake

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

07/1/10

Caster Creativity

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

6/01/10

Ackerman

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

4/28/10

Set Up Routine

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

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

3/23/10

Under Pressure

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

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/