I have the vette zr1 and have used it on the Indy track. With all the aero and suspension settings set at the original settings, 840hp, stock gearing at 390k I could turn consistant 43.6 sec. laps. Then one day with no changes to the car it was a consistant 2 sec. a lap slower. I tried a wash job and an oil change but it didn't seem to make any difference, it was still slower. Any ideas? Thanks in advance.