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/

Why We Race

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

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

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

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

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

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/