auxilary Posted July 20, 2005 Share Posted July 20, 2005 OK, so here's my scenario.... I've got a summit 16ga fuel cell with anti slosh foam and sump. I've got a walbro 255lph (67gph) external inline pump [see where the fuel pump sits?] The walbro unit is gravity fed, so it needs to be mounted either at the source level or below for best performance. However, with this setup it hangs low and outside of the fuel cell box, and is visible to the naked eye if one bends down, or looks through the wheel gap. I would like to eliminate this and flip my fuel cell so the sump is facing forward, but there isn't a lot of room. I was pondering last night, and thinking of surge tank setups... minus the tank. Have a low pressure flow pump feed from above the source through a couple of filters to the high pressure pump, possibly mounted in the engine bay. Flow is flow, right? So a 70gph low pressure pump does not require to be gravity fed, and should be able to provide ample fuel straight to the walbro unit, which is 67gph. Would this setup work, or should I figure out how to replumb the system with a surge tank, costing me another 400 bucks in tank, lines, fittings, etc. Which I don't want to do. Quote Link to comment Share on other sites More sharing options...
Phyxius Posted July 20, 2005 Share Posted July 20, 2005 i can't see a reason why you couldn't, as long as the flow rating of the low psi pump exceeded the flow rating of the high psi pump by a good bit...i think i'd want a bit more than 3gph seperating the two... I'm far from an expert in these matters, though. Quote Link to comment Share on other sites More sharing options...
2126 Posted July 20, 2005 Share Posted July 20, 2005 Just curious! What leads you to believe a low pressure fuel pump does not require the same gavity feed as a high pressure fuel pump? In your case, can you adapt an in-tank high pressure fuel pump as used in newer FI cars? Quote Link to comment Share on other sites More sharing options...
Pyro Posted July 20, 2005 Share Posted July 20, 2005 You could mount the efi pump down low on the side of the tank and cover it with a thin piece of sheet metal. It looks like it could get damaged easily under the tank. Your current efi pump will pull gas up a few inches, i'm sure. I used a mallory comp110 pump to feed my efi pump. It works fine like that. You could even mount the efi pump in the engine compartment if the low pressure pump is feeding it. That is how my car is set up. But, the in-tank pump would be the best solution. Quote Link to comment Share on other sites More sharing options...
Guest ON3GO Posted July 20, 2005 Share Posted July 20, 2005 alex.. sorry if this is off topic but what ya gonna do about exhaust? doesnt look like theres much room? on topic... why cant you just move the fuel pump alittle future down on the car? thats what i did and it worked out fine. mike Quote Link to comment Share on other sites More sharing options...
Tim240z Posted July 20, 2005 Share Posted July 20, 2005 I found that when I put in a surge tank with a low pressure pump it helped ALOT! It also made the HP pump much much quieter. As for the low pressure pump being gravity fed.....low pressure pumps tend to 'pull' fuel much better than high pressure pumps..... Quote Link to comment Share on other sites More sharing options...
auxilary Posted July 20, 2005 Author Share Posted July 20, 2005 Yeah, what Tim said about the low pressure pumps: they can suck fuel in a lot easier than HP ones. Think about the stock Z mechanical fuel pump, it's WAY above the gas tank. Same goes for the electric fuel pump that was mounted in the back, no? I am definitely considering moving the HP pump to the engine bay, I have TONS of room there Mike: exhaust? the fuel cell is offset to the passenger side to accomodate exhaust path in stock location hard to tell, but my fart can fits in there. Quote Link to comment Share on other sites More sharing options...
auxilary Posted July 20, 2005 Author Share Posted July 20, 2005 ok, on that note, I've got a better question.... If I was going to use the aforementioned setup: Fuel cell => LP pump => HP pump => engine =>fuel pressure regulator= ^ || ||================================================ (my awesome ascii diagram) Won't I need to run another FPR for the LP pump, incase for some reason it is pushing more fuel to the HP unit than necessary? At this rate, it'd be easier to do the surge tank setup, because the surgetank would be the FPR for the LP pump, correct? Quote Link to comment Share on other sites More sharing options...
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