Many top teams have sorted...
Many top teams have sorted out their setups in just the way we will outline here, and they are winning races. An example is the Bob Garbarino-owned Mystic Missile Racing operation in the NASCAR Whelen Modified Tour. The car, driven by Jerry Marquis, is shown here in Victory Lane at Waterford (CT) Speedbowl. Photo by Keith Cyr
Throughout your career, whether you're a driver, a car chief, or a crewchief, sooner or later you will have to deal with an unfamiliar race car. When faced with setting up or driving a race car with which you have no previous experience, often at the spur of the moment, there are certain rules and steps to follow in order to quickly get a handle on the car and set it up to be a winner.
As I watch others dial in a new or different car, and having worked with "new to me" race cars myself over the years, there has evolved a method and defined routine for becoming knowledgeable about any chassis and then fine-tuning it to what it should be.
I have included the driver here because he often steps into difficult situations in which he is expected to make the car perform better than the last driver. Having knowledge of these methods will help him get the car straight and up to speed quicker and make his job easier and more successful.
The following are the steps, in order of importance (with most critical first), for evaluating and redesigning an unfamiliar car.
Last season, Bobby Gill had...
Last season, Bobby Gill had to climb into a new car. The process may have been similar to the one we are explaining. First, Gill had to sort out how the car felt compared to how he likes a car. He had a lot of success with his own car over the past few years.
The absolute first thing we need to know about an unfamiliar car is the condition of the various mechanical components. We do not need to be tuning the setup and handling on a car that has bound control arms, broken shocks, worn or broken steering, a bent chassis, and cracked welds.
I have spent lots of time and owner's money on a car that the crew said was in top mechanical condition only to find out that the right-front shock was basically frozen and the steering box was very tight. We spent valuable time trying to fix the "handling" problem when in fact it was component failure that caused the car to not perform the way it should have.
Ask very pointed questions to gain knowledge of the car. "Do you know where the moment center is located?", "Have you had your shocks tested lately?", "Do you have any Ackermann in the steering system?", and "How often do you change the brake fluid?" are examples of queries that get right to the point. The answers will tell you just how much the crew knows about the car and alert you to possible trouble areas up front.
Go over the car thoroughly and inspect and cycle the brakes, shocks, control arms, steering, ball joints, and all other moving parts. Ask when the rearend was last serviced. Once you are convinced that all is right mechanically, you can move on to the next step.
Top car builders have come...
Top car builders have come to understand and accept the importance of the front moment center. Here is a jig that Port City Racing uses to check quality control of the front end geometry.
The very first thing we work with is the front geometry. There are two areas of geometry that are most important. Those are the moment center locations (static and dynamic) and the camber change characteristics.
In today's racing environment, most of the top dirt and asphalt race teams, as well as some of the top car builders, are very much on top of the moment center (MC) design in their cars. Long gone are the days we even hint at thinking that MC location is not important. It is extremely important, and the small amount of time spent on finding the location of our MC and making changes to improve it are all well worth the effort.
If you are working with a car and you don't know where the MC is, then the chances are very good that the car will never reach its true potential if the MC location is off. It all starts there. You must take the time to evaluate this area of the car. No amount of other chassis adjustment will overcome MC problems.
Regular maintenance on such...
Regular maintenance on such items as the quick-change rearend helps keep the mechanical breakage to a minimum. If possible, have a professional disassemble your running gear, such as the rearend and transmission, at least once a year.
The next geometry consideration is camber change. Camber change is a combined product of the motion of dive and rol of the front end through the middle one-third of the turns. If we know that, or can adequately make an educated guess at the motion by observing the car, then we can enter dive and roll numbers into a computer program and see the true camber change.
Camber change is dependent on chassis dive and roll combined, so knowing those movements will lead us to the correct picture of what is going on with camber change. Camber change curves that use the bump of the wheel only represent half the picture.
I recently visited the Northeast and observed a team running both an SK Modified as well as a NASCAR Whelen Modified Tour car. This is a top team, and I was asked by the driver to observe one of the SK cars in practice at Stafford Speedway. The right-front tire, on entry and through the middle of the turn, was transitioning from a negative 2.5 degrees to some amount of positive camber.
The crewchief had carefully gone over the camber change numbers in a geometry program but used the wrong dive and roll figures. When he re-entered the correct numbers, the camber loss was very evident. With relatively small changes to the upper control arm angles, the car became much more competitive. If this can happen to a top team, it can happen to you and me.