Originally Posted by
93DelSlo
i have the z6 right now and i was told that it got rebuilt right before i bought it but when compression tested i only got 135 psi across all cylinders? i thought stock was around 180 psi!? would it still be safe to boost this motor with no more than 6 pounds and tuned on crome?
i can guarantee you compression tested it wrong. More than likely its from like you said the throttle not being all the way open or from the engine not being warmed up. I would just stick with the z6 you have now. Not worth swapping for a y8. Also its been said that the z6 head at higher power levels will always outflow the y8.