I think that fuel cut is based more on injector pulse width than manifold pressure, and here is why. most all HRC stage 2 cars with stock injectors and the rising rate fuel pressure regulator hit fuel cut if they hit boost without a little black box or a vc-whatever or a missing link. think about what the nong term fuel trim is..........zero. the fuel pressure under vaccuum and at idle is just like factory, so while the ecu is reading the peripherials, it detects no need for leaning out the entire fuel map. when you run boost on it, the ecu uses a fuel map which is "quite enriched" past 4250 rpm and is basically a linear progression based on rpm and throttle position. the main reason i say this is on MuRiX's car............there is no fuel cut defense device..............and also no fuel cut ;). it however DOES go into a different fuel map once it hits boost, which is "very" evident after 4250 rpm between 0 and 4 psi (it shoots so much fuel per air that it won't burn). after 5 psi, the air/fuel mixture gets into a burnable range, and the car makes power. the air/fuel ratio seems to be slightly dependent on boost pressure, which leads me to beleive that it runs on a static base map in boost, and it seems to enter the "danger" zone at about 18+ psi with this map and 93 octane fuel and 525 cc injectors with -25% longe term fuel trim and 63 psi of fuel pressure. if the fuel pressure was higher, it would be consistantly safe, but the regulator the car is equiped with is non adjustable. all I say is if you have relatively large injectors, try zeroing out all your adjustment devices, and lower your fuel pressure so that it doesn't skyrocket under boost, and you jsut may never have fuel cut again. it's based on injector pulse width imho.

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on............