what I see. Options

[wortdog]

If you think that your fuel pump is inadequate, adding more fuel pressure will just make things worse. Fuel pumps supply less and less fuel as the pressure increases.

With a stock FPR(~37psi line off), at 20lbs of boost a 190 can supply about 125lph. If you switch to the N/A regulator(~45psi line off), you're down to about 111lph.

So, the N/A regulator will fix your problem if the 190 can supply enough fuel at 17psi and your injectors are just too small, but its not a good idea if you think the pump isn't good enough.

The stock pump is more like a 165lph pump at the same pressure the 190lph actually flows 190. The 190 is just a slightly better than stock replacement for those that don't feel like buying an AFPR.

Stock narrow-band O2 sensors also tend to read leaner as they get hotter, which is one of the reasons O2 values tend to drop as you go down the track. Wide-band and medium-band sensors have temperature compensation built into them. Medium-band sensor is a term I kind of made up to describe sensors like the Bosch LSM-11, which is in between a narrow-band and wide-band O2 sensor in terms of range of accuracy and cost. The added bonus of an LSM-11 is that its output is still compatible with ECU's expecting a narrow-band sensor.