really? I say that cause the Japan stuff is always better then US. I know for a fact that the j-spec mr2 ECU's have it like 5psi higher then the US ones with full fuel mapping .

I guess just an asumption/ remembering things wrong. I haven't seen anyone use a j-spec ecu in north america so I woudln't know off hand..

 

Just thinking out loud........seems if I had a car that was hitting 10 psi and not hitting fuel cut, I'd get a meter and see if/what my input at the ECU is from the boost/pressure sensor when I saw 10plus psi on the gauge. That and have some suspision about the boost gauge that I was reading. There are a couple of folk out there that say they run over 10psi without fuel cut and no fuel cut defender. Something is wrong about that.

 

Another myth that needs to die...
The pressure sensor controls spark timing, not fuel delivery. With an FCD fitted the ECU thinks you're running just under 8.6psi so it doesn't retard the ignition as much as it should. This will eventually result in detonation. The end result is as if a lean out had occured, but any lean condition hasn't been caused by the FCD (more likely the overworked stock fuel pump).

As for the safety of an FCD, factory tuning is always very conservative, so as long as you don't exceed 8.6psi by much, you'll be fine. The thousands of cars running these prove that. 10-11psi is as far as I'd go, but people have gone further.