setting an adjustable fuel pressure regulator

[formula69]

how do i set up my afpr so that it wont dump a lot of fuel at start up or not dump enough? i got it used and didnt get any instructions :(

[Da_lurker]

well you need to decide on what you want to run for base pressure? 32 psi? set the base with the vac line off ~40psi~ assuming it is fuel injected.. does it have a gague on it?

[formula69]

i have a gauge on the car... base fuel pressure is 43.5 ish.. its a 96 lt1... i just need to know where to set the screw in the top of the thing to first turn on the car so i dont rich or lean it out at start

[GTman85]

i have a gauge on the car... base fuel pressure is 43.5 ish.. its a 96 lt1... i just need to know where to set the screw in the top of the thing to first turn on the car so i dont rich or lean it out at start


Id just turn the car on a go by that. If it wont turn over turn it up a alittle. Thats what i did with mine. Did the same thing with the GT too. The GT wouldnt stay idled and i turned the screw a few times till i got it to stay runnin then set it

[Half Fast]

FP adjustments on an LT1 will only affect lean/rich ratio at WOT. At any part throttle setting the O2's will send the rich or lean signal to the PCM and the programming will adjust injector pulse width/duration for a stoiometric ratio (read clean emissions) with stock programming, ie:closed loop. At WOT the PCM goes into open loop and runs on set parameter tables in the programming.

Fuel pressure on a N/A LT1 is only good for finetuning WOT and is best done on a dyno with a wideband, but once you become familiar with it you can usually figure out what it needs at the track. Ive had best results with an A/F of ~12.8:1 at WOT. The pressure depends on how much the motor can breathe and what size injectors are supplying the fuel.

30lb injectors at 48psi works on my setup. :mullet: