We took the car to a Crows Landing airport course last weekend and got beat badly. I have not tuned for concrete in quite a while and it showed in spades!
We tried the new A052 Yokahama's and they did not compare well to Bridgestones, they are expensive and slow. Looking at the data we are getting killed on the brakes pulling only .9 G stopping, Corvette competition is getting 1.2 to 1.3 G braking. We got 1.16 G acceleration at 65 mph so it is putting power down pretty well except for wheel spin. It would make Mark Donahue happy because it will spin the tires the length of any straight. The traction control pulls 20 D of timing out but still not enough to control wheel spin. We lowered the car a bunch which helped everything but braking now at 2.6" front of frame to ground and 3.4" rear. I need to add roll stiffness with front bar and increase rebound but we only had 4 runs each day so not enough time. I increased spring rates by 5% but think that hurt us too. We were off 2.4 seconds on Saturday and 1.4 seconds Sunday so some progress. We were actually very close to a McLaren 720S (.1 seconds) but 4 Corvettes got by, some brand new others C5 and C6 with big horsepower. We had too much camber on both ends which will help when we reduce it but I am not sure that is the whole answer. Oh well, we will work on on a concrete tune the rest of the summer. I am also looking at a Bosch Racing ABS system for the car. Here is a video for you to watch, look at the windshield above the red light sticky taped to dash. When you see red lights in my poor mans head up display traction control is on. Scott actually smoked the tires at 8200 in third gear bad enough that we saw it from pits. Thinking about reducing available throttle opening. The red light comes on when wheel acceleration is more than 225 rpm per .1 second. We finally figured out slippery asphalt now we need to get concrete figured out.
https://www.youtube.com/watch?v=UgG0C_6XZS4