Another fuel pressure question.
Thread Starter
Melting Slicks
Joined: Nov 2000
Posts: 2,469
Likes: 6
From: Winchester Ontario
Another fuel pressure question.
I realize fuel pressure questions come up every day, but I've gotta ask one more.
I know some people run higher pressure than others, but tell me if mine is too high and will hurt performance.
383 @ 9.5:1
Super Ram
30 # injectors
Walbro GSS340 255 LpH fuel pump
FP vacuum off is 50 psi, vacuum on is 42-44 psi.
Is my pressure too high, or what would you recommend I run mine at, or is more of a trial and error with a G Tech to see which runs the best. With the trial and error thing with the G Tech, my car is a 6 speed and every run is different, as I'm certainly not a professional racer.
[Modified by black_89_vette, 1:08 PM 8/14/2003]
I know some people run higher pressure than others, but tell me if mine is too high and will hurt performance.
383 @ 9.5:1
Super Ram
30 # injectors
Walbro GSS340 255 LpH fuel pump
FP vacuum off is 50 psi, vacuum on is 42-44 psi.
Is my pressure too high, or what would you recommend I run mine at, or is more of a trial and error with a G Tech to see which runs the best. With the trial and error thing with the G Tech, my car is a 6 speed and every run is different, as I'm certainly not a professional racer.
[Modified by black_89_vette, 1:08 PM 8/14/2003]
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Another fuel pressure question. (black_89_vette)
There are two issues:
1) closed loop (part throttle) - can the ECM compensate for the fuel flow
2) open loop (WOT) - is the A/F ratio close to 12.6:1
A scan tool will provide data on the first issue and a hint on the 2nd one. You realy need a dyno or drag strip tune to get WOT fuel flow right.
1) closed loop (part throttle) - can the ECM compensate for the fuel flow
2) open loop (WOT) - is the A/F ratio close to 12.6:1
A scan tool will provide data on the first issue and a hint on the 2nd one. You realy need a dyno or drag strip tune to get WOT fuel flow right.
Drifting
Joined: Apr 1999
Posts: 1,261
Likes: 6
From: Middletown New Jersey
Re: Another fuel pressure question. (black_89_vette)
Did you get a chip burned for your setup. Chances are if you're running the stock chip and 30lb injectors you're running rich even with the larger cubes.
Thread Starter
Melting Slicks
Joined: Nov 2000
Posts: 2,469
Likes: 6
From: Winchester Ontario
Re: Another fuel pressure question. (GlennS87)
Yes, I do have an Ed Wright chip that was tweaked by a tuner from RaceTronix.
The A/F at WOT was (trying to remember here) around 12.0-12.2.
He made it rich due to the fact that I do run nitrous.
I was just wondering that with the larger fuel pump, and the larger injectors if I needed to have it at 50 with vacuum off, or if it should be around 45 or so.
I have taken it to the track twice, so I guess I could make adjustments at the track and see how it affects my time, but with me driving a 6 speed car, I'm far from consistent.
Then again, I did check my air pressure the day after the drags only to find out I was trying to launch on 45 psi. No wonder I was having traction issues, but I did manage a 2.018 in the 60, but most were in the 2.1xx range.
The A/F at WOT was (trying to remember here) around 12.0-12.2.
He made it rich due to the fact that I do run nitrous.
I was just wondering that with the larger fuel pump, and the larger injectors if I needed to have it at 50 with vacuum off, or if it should be around 45 or so.
I have taken it to the track twice, so I guess I could make adjustments at the track and see how it affects my time, but with me driving a 6 speed car, I'm far from consistent.
Then again, I did check my air pressure the day after the drags only to find out I was trying to launch on 45 psi. No wonder I was having traction issues, but I did manage a 2.018 in the 60, but most were in the 2.1xx range.
