<
>

Low-tech ingenuity gave way to expensive gizmos in helping with setups

The late Alan Kulwicki was a mechanical engineer by training but a race car driver by desire. He won the 1992 Cup championship driving for his own team that was underfunded in cash but not lacking in desire. He is credited with developing and manufacturing several front end geometry tools that helped to move the sport forward in technology.

Back then, Kulwicki would use the old mechanical-type grain scales to weigh his car during the setup process. For those of you who are unfamiliar with grain scales, think of your weigh-in at your doctor's office where the nurse has you step up on a scale and then moves the various weights to the right on a graduated line until the pointer balances in the middle. She then sighs, shakes her head and tells you to step off slowly. At least my doctor's nurse does that.

Anyway, picture that type of scale on steroids sitting on big steel casters to roll it around and you have a grain scale that was designed to weigh multiple 100-pound sacks of grain. Using the big grain scales was how race teams weighed their cars before electronic digital scales became a reality.

Harold Holly, who was with Kulwicki's team back then recalled having to roll those big cumbersome scales around the shop and also haul them to the track. They would have to jack the car up, roll the scales underneath the tires then lower the car back down and keep repeating that process until they achieved the weight distribution that they wanted.

Teams back then would use a taut string that was centered down the middle of the car from front to rear to measure and square up the suspension to the chassis and body of the car. They would hang plumb bobs down from the frame including the front pivot points of the truck arms for the rear end and then hang plumb bobs down on the front side of the axle housing on each side. They would then measure the distance on each side and adjust the rear end until it was squared to the chassis. They would measure side-to-side from the string or the rear clip by using a four-foot level across the tires to get the proper offset.

One humorous story I recall from my short track racing days was how a buddy had all of his "points" on his car marked on his garage floor so he could park the car back in the same spot after each race and quickly check for a bent frame of other damage. He had spent many hours locating all of these various reference points to make his life easier during the setup process he went through each week. His wife was not aware of his system and decided to surprise him by cleaning and painting his dirty old garage floor that had all of those unsightly marks all over it while he was off racing one weekend. She got her wish.

Years ago, the crews would chalk the sidewalls of the tires and then rotate them while holding a reference point just off the side of the tire to locate any high spots or low spots in each tire before they ran a string from a point behind the rear tire to a point beyond the front tire so that the string barely touched the center rear and center front points of the rear tire to indicate the alignment was square. You would then set your caster in the front end and remeasure after each adjustment until you had the front tire track aligned with the rear tire track so the car would run freely down the track. It was a very tedious and time-consuming process to get it right. But it was all they had back then.

Holly said they have gone from strings, plumb bobs, levels, tape measures and carpenter squares to lasers, seven-post shakers, AVL dynamometers and very sophisticated computer-aided simulation programs.

One example Holly gave was how they now check "square" with lasers instead of string.

"We locate a laser on the center of the driveshaft and pinion to measure between the frame rails to center it up and to also align the rear end, pinion and tail shaft of the engine to get them perfectly balanced," Holly said. "This helps to keep the engine from sitting at a twisted angle on the motor mounts, which can kill horsepower especially on restrictor plate tracks where every ounce of power is critical."

They don't chalk tires anymore either, Holly said.

"Now we use lasers that are mounted on machined plates that mount directly onto the hubs so we can check cross alignment, front-to-rear alignment and toe, etc. simply by pushing a button," he said. "We used to use toe plates that we would set up against the outside of the tires and then measure across front and back with a tape measure to calculate how much toe we had in the front end."

Today they use the electronic digital scales that can provide instant total, cross, side and front or rear weights and percentages at the touch of a button. The scales can be set into scale stands that can be individually leveled so all four scales are perfectly level with each other every time they are used. Drive-on and connecting ramps allow the teams to roll the cars up on the scales, weigh them, back them off the scales and make adjustments. They keep repeating the process until they achieve what they want.

One interesting aside to this process is the recent canting of the rear wheels to the right on the Cup cars makes it very difficult to roll them onto and across the scales because they want to crab walk sideways instead of rolling straight.

Holly made the interesting point that years ago they would work to be within a 32nd of-an-inch tolerance where today they work to the low thousandths-of-an- inch for tolerance. Sometimes less than five one-thousandths-of-an-inch to be exact. To put that into perspective, a 32nd of-an-inch equals about 31 thousandths so they are now more than six times more accurate than before.

Interestingly enough, one tool that was used back in the old days is still preferred today, Holly said. The old bubble balance caster-camber gauges are considered to be better and more accurate than the newer digital gauges so they still prevail with most setup specialists, he said.

One note for you amateur setup specialists. Do not follow the manufacturer's instructions on how far you turn the wheel when setting the caster. Race cars don't come close to turning as much left or right as a street car so work within the turning radius you anticipate using on the track and you will be more accurate.

Note that most of the above setup descriptions are performed on a surface plate. A surface plate is simply a large slab of steel that is perfectly flat and level on the floor, which allows the teams to work off a known surface when making measurements, etc.

In the old days the surface plate was the ultimate in technology for the teams but today the teams now go beyond the surface plates to pull-down rigs and/or seven-post shakers that allow the teams to measure dynamic weight shifts and suspension travel, etc. The cost difference between a surface plate and a seven-post shaker is only a million dollars or so.

ESPN commentator Andy Petree is generally credited with developing the pull-down rig, which basically works by tying the car down to the fixed rig while the four tires rest upon hydraulic rams that can push up to simulate suspension compression going into the corners, etc. Load measuring cells are in the rams that can give the team feedback on suspension deflection, spring loading and unloading, etc., which goes a step beyond the static weight measurements they can get off a standard surface plate.

However, both of the above setup methods pale in comparison to the seven-post shaker the big teams such as Hendrick Motorsports have at their disposal. The shaker can simulate on-track conditions by creating yaw, dive, squat and other various lateral, longitudinal and vertical force loads that a race car experiences during competition.

Couple that with the AVL Dynamometer and some track mapping software and you can easily become buried in new technologies that are moving the sport away from human ingenuity to hard scientific data and less and less creative interpretation.

So we have progressed from using grain scales to all sorts of gizmos and gadgets and technological advancements such as the seven-post shaker that make setting up a race car easier and more accurate than ever before. It also makes it a whole lot more expensive. Teams now spend millions and millions of dollars on technology to gain an edge or to just stay up with the pack.

Even simple things such as timing a car on the track has gone from the human eye and reflexes to punch a stop watch to transponders being carried on the cars that can give exact time measurements in various segments of the track. It is more accurate and reliable but not nearly as much fun.

Teams can now test with all sorts of sensors and load cells placed on the cars to measure downforce, spring loads, lateral, longitudinal and vertical loads, shock travel, individual spring movement, steering input, throttle input, tire pressures -- all dynamically as they happen versus being static on a surface plate back at the shop. Teams can aero map a car as it goes around the track to see how and where the air is moving across the car body surface. The list goes on and on.

The information gathered has become much more concise and the computer simulation packages have become far more sophisticated in the past few years and are now much more accurate in duplicating what is actually happening on the track. Crew chiefs can now sit in their motor homes the night before a race and play "what if" with chassis changes on a computer versus playing poker like we did years ago. They literally can see what impact any change should create on the car and be comfortable and confident it is accurate if they call for it to be made during the race.

You will sometimes hear fans or critics complain that the racing isn't nearly as good as it used to be. In some ways that is true depending upon how you measure it. But if you are a Carl Edwards or Jimmie Johnson fan in particular then you currently would have to take exception with that premise.

So, with all of the added horsepower the teams have gained over the years [from 500 to 800] and all of the technological advances they have achieved in that same time period, Why aren't they constantly setting new track records every time they qualify?

That is an excellent question and it was posed to me by Frank Edwards who has been with Hendrick Motorsports since its inception and has worked with many name drivers in that time. I noted to Frank that it was a great question and one I had not thought of over the years.

Edwards' belief is the old cars were slick and cut through the air and were not aero dependent like the new cars are so all of that aerodynamic downforce that has been gained is also creating added friction and therefore there is not that much gain in speed. It makes total sense to me when you think about it. They have concentrated so much on making the cars stick to the track better that they have offset their gains in horsepower.

To me, Edwards' point just validates the old racing adage that everything is a compromise on a race car. It is just basic physics that you cannot gain something in one area without giving up something in another area. Take the example of when a team member cranks wedge in or out of a rear corner on a pit stop. If he cranks wedge into the right rear he is creating more load to that corner but he is also adding load to the left front wheel and decreasing load to the right front and left rear. How much depends upon the spring weights, etc. but he is changing all four points on the car.

Edwards and Holly pointed out that the old spring rate setups are almost totally reversed from today's set ups. Holly gave the example that today's combined weights across the rear are from 1,500 to 2,200 pounds and the front weights now generally range from 750 to 800 pounds. You might run 700/1,200 springs across the rear and 350/400 springs across the front today.

That compares to 3,300 pounds of combined front end spring weight and 625 pounds of combined rear spring weight in an old setup. Dramatically different. Especially when you calculate in the added aerodynamic downforce the teams have gained on the front ends.

Holly said the reasoning behind the dramatic change is to get the nose of the car sucked down to the track surface and cut off any air flow underneath the car, thus creating greater downforce on the front end. Combine that with the coil binding shock setups and you have created a tremendous amount of load on the front tires. As Holly said, "More load equals more grip." Frank's point is that any added aerodynamic downforce creates added friction, which in turn will slow the car down. Plus they are beating the hell out of the front tires with the new setups.

It would appear the concept has been engineered to the extreme, which is often the case in racing. The old "if a little bit is good then a lot must be better" theory that permeates modern-day racing minds.

One interesting point is that when I asked Holly and Edwards separately to give spring rate examples of what worked back in the old days both gave me identical front rates and were just 25 pounds different on the rear rates. It's physics, folks!

Edwards made the point that he has been "messing around with race cars since I was 13 years old. I look at these car setups today and wonder what they are doing. I really think if they come off these bump stops they would improve their speeds. They have more horsepower but they don't break any track records" he pointed out.

Edwards and I had a brief discussion about how great a driver Tim Richmond was and how he would have changed the sport if he had lived. Edwards worked with Richmond for several years when the driver was with Hendrick.

Frank gave the following example to prove his points about aerodynamic downforce and how good Richmond was as a driver. Richmond and the late Al Hobert were testing some Porsches one time and Richmond was blowing Hobert away because Richmond's car had a lot less downforce than Hobert's. Hobert took away downforce on his car and gained from 212 mph to 228 mph to catch up with Richmond in speed. Richmond then went back out and ran 240 mph. The test was over.

Bill Borden is a former championship winning crew chief who operated David Pearson's Racing School for many years.