Im sry Im currently running 10psi, the bottom is all fordged and the head has been ported and polished I was told that I could run 15psi and the turbo be reliable and could run 17 to 19psi but the turbo wouldnt hold up. The car also has a r33 lsd diff. Its my first turbo car im used to my supercharger foxbody mustang. The 240 pulls real hard and is a fun ride though