USAR Project Car Report

Coincidentally, in our previous test we saw the same phenomenon. The LF was always hotter than the LR. The one big difference in the two setups was that the difference between the average left-side temperatures in the first test at Concord was 23 degrees and the difference between average temperatures side to side in the final runs on Saturday showed a difference of 30 degrees. In Saturday's case, the right-side temperatures were showing the same average within a couple of degrees, more on this later.

In the race, the car ran in the top 15 for the most part; the team had to deal with a loose RF wheel that was the result of a bad wheel. Then John had a collision with another car that bent the right truck arm. It was unfortunate, since he put down a good qualifying lap and advanced in the race up until he tangled with that other car. John did the best with what he had and did improve his position.

On To South Georgia
The next USARacing race was at South Georgia Motorsports Park, a flat track with lots of grip. We returned to the original setup we had in the first Concord test with the exception of using a 1.875-inch diameter sway bar, a 500 ppi RF spring and a 525 ppi RR spring. This was a compromise between what was raced at Concord and our original setup. We also reset the shocks to where we ended up at the end of the first test at Concord with the LF heavy in rebound.

We initially expected the car to be loose with the South Georgia heat in the middle of the afternoon, but the opposite happened. The car was very tight off the corners. I spoke with Justin Lages, John's crew chief, after the race and he said the car looked good in and through the middle, but developed a severe push coming off the corner.

I was not able to attend this race and the team was not able to communicate with me during the practice sessions. Admittedly, this would have been difficult with the noise in the pits, but in hindsight, I might have been able to help. My first reaction after studying the practice notes was that the LF shock's high rebound settings might not be right for this track. That could have served to tighten the car too much coming off the corners.

Unrelated to that, the battery discharged during the race and had to be replaced several times dropping John laps down at the end. We discussed the entire event and I concluded that some mechanical problem might have been the culprit for the handling problems. No matter what the team did to free the car up, it always had the push off.

The changes made included raising the track bar, putting successively larger springs in the RR up to an 850 ppi with a full spring rubber, and moving the right truck arm back 1/16 inch. Changing the rear alignment to loosen a race car is considered a crutch, but in desperate times we do what we have to do.

In my computer analysis, the changes, if made to a car without any alignment or mechanical problems, would have made the car so loose John wouldn't have been able to drive it. When these extreme kinds of changes don't produce the desired effect, the team must start looking for the problem, because there is a problem.

Again, note that if your handling problem occurs in the transitional phases of entry or exit, the base setup usually isn't the problem. With the "real tight off" problem, as described by John early in the practice, I would have suggested taking rebound out of that LF shock to see if it was overpowering the setup. If that didn't work, we would have looked at alignment of the rearend because some work was done there to straighten the truck arm and the rearend could have ended up misaligned. Another setting that I have not checked personally is one of excess Ackermann.