I got a Accel AFPR cheap and installed it on my car along with an accel SR base. I set the pressure at with zero vaccum about 45 psi. My book says between 41 and 47. When would I want to change it? I assume I would want to increase it some when I go to the drag track, but to what? What other conditions I would want to change it. I guess if I get some higher injectors and a custom chip right? Thanks

Just make several passes on an empty stretch of road with a stop watch until you go the same distance in the shortest amount of time (assuming you can launch consistantly).
-- Po' mans tuning guide

OK, thats it, once and for all, there is no specific setting for best performance. You use it as a tuning tool, measure performance and adjust and repeat.

Aye I should have mentioned to adjust between passes.

Larry,

Head to the track and bump the pressure to 50psi. Make a run. Then back it off in 2lb increments until the car slows down. Then bump it back up 2psi.

Use the trap speed, not the E/T to see if the car has slowed.

Prom burning is the way to go... set it to 43.5psi and do all the fueling changes in the prom.

The only accurate way to set the pressure is by going to the dyno.

Or use a scan tool until your Air/Fuel or BLMs are where they are supposed to be. 14.7 A/F I think and 128 for the BLM.

OK, I guess I need some basic advice here on setting the pressure. I went to set it a 43.5 psi as was suggested here. I set it with the motor running and the vaccuum fitting connected, to 44psi. Then I remembered I read you are supposed to set it with the vac fittins disconnected. So I pulled the fitting off and it goes up to like 51psi. So I begin to back out the little adjusting bolt and it gets down to about 49 and begins to suck air through the bolt. So I screwed it in a little and left it. Now with the motor running and the vacuum fitting on i get about 42 and with it off about 50. I like the idea of doing a dyno test to be sure of best performance but that would be a little expensive. What it is the factory setting? I know my gm manual says 41 to 47, and I assume that is either with the key on and the motor off, or with the motor running and the vac line disconnected right?

by the way, whats BLM?

thanks