.68 ar/ they make power untill your motor cant rev any more and how much boost determines how much power they make, from the start of a pull to the end i gained about 50whp, my dyno was done in mph rather than rpm but with in 5mph it went from nothing to just under 500whp and stayet right around there for the rest of the gear, you put the go pedal down and the second the turbo lights up its over 5k rpm