Im actually not 100% sure lith but im pretty sure 21psi in 3rd gear is around 3500-3700 max and 4th gear is unknown mate my car is supposed to be hitting the rollers thursday so keep ya eyes peeled in my GTX3071 thread mate to check out my dyno sheet. Wolverine actually drove my car the other day and was of the opinion there was a little more to be had down low. So fingers crossed hes right