Well, the red on the tach starts about half way between 6,000 and 6,500. You are right, the car didn't seem to make any extra power past the indicated redline. I was just suprised that the computer didn't cut the spark or fuel delivery when I got it 6,500. My 89 Maxima cut it off at about 6,200 with a redline of 6,000. I think I will hold off on testing it.....no reason to stress an engine with 140,000 miles with unnecessary abuse. I was just curious as if there was a limiter on it and what the engine could really rev to. 6,250 seems a bit conservative to me for a Honda/Acura engine.