The amount of psi depends on the turbo. Typically 4-7psi depending on how much air it's flowing. On my stock wrx turbo at around 6psi I'd just hit 4.9v on the stock MAF.
That did 146whp and 170wtq on the stock fuel and ECU. My downpipe is 3" though and my exhaust was leaking at the flex pipe, but the exhaust was needing to be redone anyway.
Yeah, odds are your big MAF is messing up your whole setup causing you're poor fueling.
2000 Rio Red I4 Cougar
200whp & 210wtq at 9psi
254whp & 276wtq with NX 35shot
WRX TD04 Turbo, Cut Short Shifter, Strut Tower Bar, 17" ZN Wheels, Roush Springs, Starion Intercooler, NX 35 shot, HKS SS BOV, Full 3" exhaust,StreetFlight Chip
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