Originally Posted by llBlazin_llLo
if you use an aftermarket regulator that is adjustable and increase the base pressure of the regulator, the amount of boost to max out the pressure of the pump will be less.
The PCM will also compensate for changes to the base fuel pressure, negating them over time by changing the fuel trim value.
The slightly higher pressures that I run give me more efficient atomization of the fuel, translating to slightly more efficient power and fuel economy. I noticed an immediate difference when I switched from a new stock 3.0bar regulator.
The PCM will compensate for pressure changes, but not by affecting the regulator itself, rather adjusting the duty cycle of the injectors. This is fine. A 29lb injector is still capable of higher than stock flow at a higher than stock fuel pressure. You still get the advantages of running a higher pressure and a lower duty cycle, assuming your PCM is capable of figuring out what the sensors are telling it.
In my case, I was running lean on the top end because I increased my port velocity in the LIM. Running the Gen3 swap on the top end with a 95 TB and MAF I was able to boost my fuel pressure to solve the problem permanently. This will not be true in all cases, but it was in mine. The FPR was chosen after careful consideration and discussions with several experts in the field. All agreed it was the best solution. It'* important to keep in mind that you MUST have a good fuel pump before using an adjustable FPR at a higher pressure.
We have another car here (2k+ SSEi) in the 13'* that chose to adjust fuel pressure rather than go with larger injectors. It worked perfectly for him. FIE backs this up. The higher fuel pressure negates the need for larger injectors up to a point. And delivers more efficient atomization of the fuel.