Juiced2jz

1996 SC300 NA-t

Ill just cut to the basics, i know my way around cars im just looking for better info specific to the SC300 NA-T guys. My setup currently is the xs power kit with a cx racing T70 turbo (.96 AR turbine), SAFC II on factory GE ecu, 100% stock fuel system, stock head gasket, cxracing hks knockoff 50mm wastegate with 8psi spring. The vehicle is a 96 so i have OBD II and the hotwire maf and as such placed it in the intercooler piping before the throttle body in "blow through" not on the intake of the turbo. I set my base timing to 8* following the FSM. I think those are the only things that really matter so to speak.

Here is my issue, all i wanted was a nice 300whp to cruise around with nothing crazy so this was more of a budget build for me and i didnt go out of my way to upgrade uneeded things. I thought our stock fuel system was up to the task of 8psi even on a turbo such as a T70. As soon as i hit full boost around 3800rpm its fine at 11.2AFR but 4500rpm it climbs to 12.8 and i let off obviously. This is a recurring theme for me as soon as it hits 4200-4500 mark it leans WAY out. Now ive gone as far as adding 50% on the SAFCII in those ranges which initially what got me there before it was high 13s. So knowing what i do i assumed the fuel pump was dropping voltage so i did the fuel pump ECU bypass mod and got it running like that. No change at all except faster starts now. Ok next step i changed the fuel filter out (what a nightmare by the way WOW). Test drive and again the AFRs are still doing the exact same thing. Something to note is my part throttle feels great and the old filter had brown crap come out im sure it was the orig one with 130k on it.

That brings me here, now for the guys that have been in this position before or with similar setups did your stock fuel system take this? I just ordered a walbro 255HP pump and sock etc that ill be putting in this coming week. It was my understanding that the stock fuel system was up to the task so i am a bit confused. Im also hoping im not missing something important. The FPR is getting proper signal direct from the intake manifold there is a little solinoid that the FPR used to go to and then the intake manifold but i removed that from the equation, is that okay to do? I saw on my 92 i dont have that i assumed it had something to do with it being a 96. Thats the only other strange thing i could thing that would be messing with my fuel but i mean the stock FPR is seeing boost and theres no leaks anywhere so idk.

I realize my stock injectors are/will be maxxed out in duty cycle but like i said im only looking for 300whp and i assumed 8psi would be a nice safe # to get near that without having to worry about upgrading injectors or head gasket etc. If anyone has any insight on this that would be great. Even if its just telling me im correct to assume the factory fuel pump is old and tiered and or is weak and once i put the walbro in i should be golden .

Thanks in advance

scblackout

iTrader: (2)

Not Na-t yet myself, but I seem to remember reading about this exact problem in the tt-ecu thread. Because our ge ecu has zero understanding of boost, Beyond that, gotta let the experts jump in.

lexforlife

iTrader: (7)

Good luck fighting with stock ECU not liking what safc is trying to do, been there done that .. ge ECU has no lookup maps for positive pressure