Qc Flatlander
Veteran
Anybody can help me...... I run an MPI STAGE II KIT on my apex (12 PSI on pump gas at sea level with 10:1 head shim) and I want to know how I can upgrade my fuel system to have a constant fuel pressure to add more boost (like 15 PSI).........Now I run a Walbro 255LPH (#GSL392) in sequence with the OEM fuel pump ?
mulot30th
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this is a bit weird.
as I personnally ran up to 21 psi of boost using stock fuel rail and pressure regulator (with bigger injectors) and a walbro gs 396 pump with stock fuel pump eliminator kit. ANd I know I can go with more boost using this fuel system.
WIth bone stock fuel system and stock fuel pump I have run 11 psi no problem.
With stock fuel pump and msd inline fuel pump I have run up to 18 psi of boost with no problem again.
hope this helped you
as I personnally ran up to 21 psi of boost using stock fuel rail and pressure regulator (with bigger injectors) and a walbro gs 396 pump with stock fuel pump eliminator kit. ANd I know I can go with more boost using this fuel system.
WIth bone stock fuel system and stock fuel pump I have run 11 psi no problem.
With stock fuel pump and msd inline fuel pump I have run up to 18 psi of boost with no problem again.
hope this helped you
07STI_Matt
Pro
What about an areomotive 1:1 fuel pressure regulater?
t_thall
Extreme
i run a 255 in-tank w/ the stock pump removed and an aeromotive 1:1, have only had it to 15psi at sea-level on my yamaha, but i know these pumps are good to 500hp on a ls1.
mulot30th
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osp drag race sled (apex engine based)
with a boost a pump we got a supercharged ls1 with the gss340 fuel pump to 670 RWHP on a dynojet.
but that is the very end of what we can get out of that pump.... fuel pressure drops at high end and we compensate this by increasing injectors duty when that happens.... playing with fire there....
also got my personnal ls1 on nitrous to 558 rwhp (same day same dyno) on the same gss340 pump (with no boost a pump) and there is a bit more left as my fuel pressure does not drop so much.
but that is the very end of what we can get out of that pump.... fuel pressure drops at high end and we compensate this by increasing injectors duty when that happens.... playing with fire there....
also got my personnal ls1 on nitrous to 558 rwhp (same day same dyno) on the same gss340 pump (with no boost a pump) and there is a bit more left as my fuel pressure does not drop so much.
rxrider
Jan-Ove Pedersen
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Qc Flatlander - welcome to the site.
Please add your location in your user profile, it's a site requirement.
rxrider
TY Management Team
Please add your location in your user profile, it's a site requirement.
rxrider
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Qc Flatlander
Veteran
Thanks to all of us for your help.........I see some failure in fuel pressure when I close the gas in high boost condition (15-18 for me.......)....maybe I'll try to connect FPR in IC instead of T-boddies and keep same fuel set-up.
Sorry RXRIDER I'm a NEWBIE !!!.......it's already added.
Sorry RXRIDER I'm a NEWBIE !!!.......it's already added.
rxrider
Jan-Ove Pedersen
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No problem Qc Flatlander and thanks 
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