In the days before we leave the shop we must prepare a plan of attack which defines what changes we'll make in what areas. This can be on paper or by making mental notes. The plan should be discussed with the entire crew so the members can have input into the process as well as being able to know the direction the test will go so they can be prepared in their particular areas of expertise.

Having a prepared plan is very important for getting good results. As the test proceeds, each change can be noted as to the results, both positive and negative. We learn probably more from the negative results than from the ones where gains are made. That's because we more readily remember losses in lap times and how to avoid those things that the car doesn't like.

If different combinations of spring rates are to be used, weight the car with each combination of springs and note the position of the spring adjusters, be it the coilover rings on the shocks or the jack screws used in the big spring cars. That way, we can quickly make spring changes at the track and be sure the weight distribution hasn't changed.

We need to mark the shocks as to the corner of the car they will be used on, as well as to their set numbers if we intend to compare different layouts of shocks when making individual corner changes. The tire sets must be marked as well so that we don't mix tires among sets. Using a tire of a different age than the other three (meaning date or laps used) can throw the setup off quite a bit. Many tests have been upset by the use of an odd set of tires.

Arrival
Once we have arrived at the track and unloaded the car, we need to establish a pitting position for the car that is relatively level. We should have easy access to the tool cart as well as the trailer and other track facilities that may be needed. Mark the spots around the tires with duct tape so you can always park the car in the same position after each run.

You should level the scales in that location and note the ride heights and weight distribution. This will ensure that you'll always know the correct values for your weights.

Weight the car before testing and after all of the testing is done at the end of the day, reweigh the car to see how the weight distribution might have changed from the various adjustments.

How to Measure Track Performance Once we hit the track, we need to be able to measure our on-track performance. There are two components to speed, the motor/drivetrain combination that gets us down the straight-aways, and the chassis setup combination that gets us through the turns. Since we work on these separately, we need to measure them separately.

A car can be the fastest one in the turns and be off down the straights due to a number of reasons. If we have lap times that include turn segment times, we can then compare our times with our competition. Turn segment times tell us all we need to know about chassis setup experimentation.

You should always take turn segment times in addition to total lap times and make comparisons of both to other fast cars. Remember that if we can improve the mid-turn speeds, we'll usually also improve the straightaway speeds. It's generally accepted that speed gained in the turns is carried all of the way around the racetrack.

If using previously run tires, take into consideration the age of the tire when making comparisons to other cars. If we start on stickers and then run 50 laps of testing, we can expect to lose time to the tires. If our lap times stay consistent, then the changes we're making are probably increasing our performance. Eventually switching to newer tires will show the positive results of our changes.

Don't chase a competitor who has newer tires than you. If we struggle to make adjustments to try to make up the 3 or 4 tenths difference in tires, we could well be putting our setup out in left field, never to return.