Modifying stock fuel lines?
- Thread starter MNwe4
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You would think that since a twin 255lph pump will work on a stock car all the way up to an 8 secound car without any modifications,people would be all over it.
just installed a dw pump on a 99% stock car. car came in with a no start condition. pump would only pressurize the rail to 10 psi sometimes 20. i installed a DW pump. started the car and rail pressure was at 50psi line off. i adjusted the regulator down to 42 line off with no issue. overwhelming issue? i think not.
maybe i should have just installed a reds double pumper... maybe i can talk him into something he doesnt need
maybe i should have just installed a reds double pumper... maybe i can talk him into something he doesnt need
It sounds like you're saying that there's no chance of creating a high idle fuel pressure problem when installing one of these higher volume pumps on a turbo Buick. Are you saying that Sakudog,MNwe4, the many people who have posted this problem,Eric Marshal,and the many people who have contacted me for advice on how to lower their fuel pressure are lying?
Ok, it's clear that no two cars are alike. The tolerance on the wall thickness, outer diameter, and bend radii on the stock fuel lines built in the '80s was probably very forgiving. Add to this the quality of wire and grounding to the fuel pump along with how well the alternator is working and it's understandable why these new pumps work in some cars and not others without modification.
From what I've gathered there is no guarenteed modification to make the stock lines work every single time. You just have to try something and go from there. This is why I just decided to leave the lines alone and see what happens knowing that the possibility did exist that they may work and I'd be done. Not the case and seeing that it's 11psi above where I'd like it to be I made the decision to replace the return instead of drilling. I know my tank/pump is very well grounded and has good voltage going to it and maybe the TT340 is just a little stronger than the DW, who knows. Parts will be here tomorrow and it will be another fun, although cold, weekend.
From what I've gathered there is no guarenteed modification to make the stock lines work every single time. You just have to try something and go from there. This is why I just decided to leave the lines alone and see what happens knowing that the possibility did exist that they may work and I'd be done. Not the case and seeing that it's 11psi above where I'd like it to be I made the decision to replace the return instead of drilling. I know my tank/pump is very well grounded and has good voltage going to it and maybe the TT340 is just a little stronger than the DW, who knows. Parts will be here tomorrow and it will be another fun, although cold, weekend.
It's now a topic that you have first hand experience with so you can talk about it with authority. You won't just be repeating something you heard.
I think these two,along with the Aeromotive pump sold at Racetronics,have similar pumping capabilities.
forcefed86
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- Jul 28, 2005
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Why is everyone so set on having low fuel pressures? Another option would be using the factory lines, run an intank 255 and an inline 255. Activate the inline 255 under boost and keep your fuel pressures high enough to compensate for the smaller oem fuel lines. Keep your fuel pressure below 100 and you'll be fine. Local at our strip runs a set of 80lb injectors well into the 900whp mark on e85 with 68psi base and 92psi under boost. Using -6 fuel line through the factory 3/8" fittings on the OEM fuel rail. ) Using 3 255's. (LS 5.3)
pmoore4321
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I can say with certainty that the stock return line will be over-powered by the Denso "Supra" fuel pump. I just ran a new return line and now my fuel pressure will go below the 43# it was stuck at before. The vacuum line had absolutely no effect on the pump pressure before the mod. I believe the drilling of the Saginaw fittings to 11/64" would have worked because my hose barb orifice is that size. I ran new -6 line because I plan to go to E85 in the future with the Racetronix setup.
Discount Hydraulic Hose part numbers 9069-06-14, 104-0404C, and 2404-06-04.
Discount Hydraulic Hose part numbers 9069-06-14, 104-0404C, and 2404-06-04.
Rafs-T-Type
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I can say with certainty that the stock return line will be over-powered by the Denso "Supra" fuel pump. I just ran a new return line and now my fuel pressure will go below the 43# it was stuck at before. The vacuum line had absolutely no effect on the pump pressure before the mod. I believe the drilling of the Saginaw fittings to 11/64" would have worked because my hose barb orifice is that size. I ran new -6 line because I plan to go to E85 in the future with the Racetronix setup.
Discount Hydraulic Hose part numbers 9069-06-14, 104-0404C, and 2404-06-04.
What's that buick plate do-hickey on your intake?
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- Feb 18, 2006
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- 10,084
EGR block off plate 
Running two 255s inline flows a significantly less amount of fuel than two pumps that have their own pickups,ie a double pumper.
pmoore4321
Member
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- Jan 10, 2010
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What's that buick plate do-hickey on your intake?
Some people call it the EGR block of plate. I call it a major source of vacuum leaks....Mr. J.B. Weld helped me with that....
Rafs-T-Type
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EGR block off plate
For some reason I didn't think the plate went anywhere near there. You're supposed to be my mentor Rick. C'mon, fall in
. I hope you are still around come spring. I have a stack of parts, and more are going to be coming. A bunch I will try on my own though. I might ask you to check out what Lyons looks like - Joined
- Feb 18, 2006
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For some reason I didn't think the plate went anywhere near there. You're supposed to be my mentor Rick. C'mon, fall in
I run 80# injectors with DW pump, a KB BAP set at mid range, drilled Saginaw fittings and a single alky line using a 15# halo nozzle. IDC builds from 74% to 80% with boost ranging from 24-25#'s. Crosses the line at 5740 RPM with AFR of 11.1 doing 131.88 MPH and no knock at any point.
