what does a adjustable fuel pressure regulator do?

[gunter96ws6]

i was told i could i could gain from one, what does it do? thanks~gunter

[Joe 1320]

The gain is a short term gain. The increased or decreased fuel pressure alters the amout of fuel going into the engine. The problem is that the computer will "relearn" and readjust duty cycle of the injectors to put the air fuel ratios back to the percentage dictated by the computer. If you want a reliable and long term power increase, a different target air/fuel ratio in the computer program is required.

[gunter96ws6]

what if i were planning on getting a bottle, would it be to my advantage then?

[Injuneer]

Nitrous shouldn't change anything. You tune the engine for running without the nitrous, then you set up the nitrous system to supply the fuel that matches the nitrous system. With a wet system, you tune on the bottle with the "fuel" jet. With a dry system, you tune (sort of crudely) with the fuel pressure... but you have to let the kit adjust the fuel pressure, not an adjustable fuel pressure regulator. Generally, the kit will use a small slipstream of nitrous, through a dedicated gas pressure regulator, to apply a pressure signal to the vacuum compensation port on the fuel pressure regulator, to boost fuel pressure.

About the only thing an adjustable FPR would be good for would be stretching the capacity of the stock 24# injectors if you were making more than 400flywheelHP. But you would have to tell the PCM what you had done, by adjusting the injector flow constant in the PCM.

[gunter96ws6]

well how do i tell the pcm what ive done?~gunter

[Joe 1320]

You'll need either LT-1 edit for OBDII, or a custom PCM program from Ed Wright or pcmforless.com A power programmer won't cut it.