I lost 7 seconds!

[jimbbski]

I just got back from a MCSCC race at Road America. I qualified at 2:56 which while not fast was faster then a CRX and a 1/2 doz. Miatas. I messed up the start when I missed a shift, that's on me but during the rest of the race I went backwards and all due to lack of speed on the straights!

The engine did seem to rev slower during the race but the water temp never went above 190 and the oil ran 220-230. My wideband O2 meter showed A/F reading in the mid to low 13:1 range at full throttle, which at RA I'm at 97% of the time! The A/F could be a bit lower but it actually read a bit higher during the morning qualification! The air temp was a bit higher for the race but no more then 10 deg.

While I haven't looked at the car yet I did find one thing different after the race. I built an air dam for this race and the material I used while cheap is brittle. I cracked it loading the car on the trailer but repaired it. When I returned to my paddock space after the race I found a piece of the air dam material laying there where it broke off as I must have pulled out to go to grid before the race. It was only 15 inches long and while about 2 inches at the widest it tapered to nothing at the ends. It would constitute about 10-15% of the total area of the air dam but along the lower edge. Cound this be the problem?

Ground clearence for the air dam was only 2 7/8 inch which is actually to low as the wheel rim is 3 inches from the ground. I was 1/8 inch illegal! I am going to raise the cars ride height a bit for the next race so this problem will go away.