What's a safe fuel pressure?
07-15-2008, 04:20 PM
#1
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Join Date: Sep 2006
Location: Michigan
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What's a safe fuel pressure?
Last year I ran my 85-z on a "babyshot" (50 hp) of nitrous with no problems. The Edelbrock wet plate kit was working awesome. Towards the end of summer it started getting a rattling sound from the solenoids. I knew it was from the FPSS because it did the same thing when I was setting it up. This year I got out my car and realized that I had a fuel "problem". I tried adjusting my FPSS down to a suitable level, but it seems really low.
What is a safe fuel pressure to run my nitrous system at? I've got a stock mechanical fuel pump that was new early last year. Is it dying out? or just not keeping up with the fuel consumption when I'm spraying? I DID have my FPSS set to around 8psi but now it seems like while I'm spraying it will fade all the way down to like 5 or 6 psi (I bypassed the fpss to doublecheck that it was the problem). I like to think I had learned my limits with the 50 and was thinking about kicking it up to the 75 or 100 jets, but if this is a problem with the 50's I'd hate to blow up my motor increasing the nitrous to a bigger shot. Any suggestions?
What is a safe fuel pressure to run my nitrous system at? I've got a stock mechanical fuel pump that was new early last year. Is it dying out? or just not keeping up with the fuel consumption when I'm spraying? I DID have my FPSS set to around 8psi but now it seems like while I'm spraying it will fade all the way down to like 5 or 6 psi (I bypassed the fpss to doublecheck that it was the problem). I like to think I had learned my limits with the 50 and was thinking about kicking it up to the 75 or 100 jets, but if this is a problem with the 50's I'd hate to blow up my motor increasing the nitrous to a bigger shot. Any suggestions?
08-14-2008, 12:45 AM
#2
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Join Date: Sep 1999
Location: MI
Posts: 2,342
A stock, engine mounted mechanical fuel pump? Feeding both the engine and nitrous solenoid? The nitrous kit is designed to operate at a specific pressure. It's probably 6 psi but don't quote me...you'll need the correct jetting and pressure numbers.
My stock EFI pump had a hard time keeping up with my 305 carb and nitrous setup. Both ran at 7-8 psi off of one regulator and they kit would delay a good 2-3 seconds when activated because the FPSS was set at 6psi and my pressure would dip down to 4 psi when the kit was activated...it would climb back up to 7-8 and the nitrous would kit. More fuel pump and seperate regulators is the solution for this. Keep the carb happy at a set PSI with one regulator and tune the nitrous system with a seperate regulator. Goodluck!
My stock EFI pump had a hard time keeping up with my 305 carb and nitrous setup. Both ran at 7-8 psi off of one regulator and they kit would delay a good 2-3 seconds when activated because the FPSS was set at 6psi and my pressure would dip down to 4 psi when the kit was activated...it would climb back up to 7-8 and the nitrous would kit. More fuel pump and seperate regulators is the solution for this. Keep the carb happy at a set PSI with one regulator and tune the nitrous system with a seperate regulator. Goodluck!
08-18-2008, 12:07 PM
#3
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Join Date: Sep 2006
Location: Michigan
Posts: 82
Yes, and I read my nitrous manual (imagine that, it had some useful info I forgot about) and it said fuel pressure should be at 5.5 psi.
Thanks for the reply AutoRoc. Do you have any suggestions on regulators?
Thanks for the reply AutoRoc. Do you have any suggestions on regulators?
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