Guest 79Datsun280zx Posted March 14, 2004 Share Posted March 14, 2004 Im going to need to upgrade my fuel pump for my new engine mods and i was wonding...what if i hooked up two regular turbo pumps together? Iv heard of twin pumps before and iv got these fuel pumps sitting around. Or would it just be a better idea to pay the cash for a proformance pump? Quote Link to comment Share on other sites More sharing options...
Ben Posted March 14, 2004 Share Posted March 14, 2004 That is a perfectly valid way of near-as-doubling your fuel flow. I've found that an L24E pump will flow just enough for about 240HP - it's a quiet, self-priming pump. So when I upgrade my Turbo motor with 550cc injectors & forged pistons, I'll be fitting a second pump of exactly the same specification. Much cheaper than a new Bosch motorsport pump.... Quote Link to comment Share on other sites More sharing options...
Guest 79Datsun280zx Posted March 15, 2004 Share Posted March 15, 2004 lol thanks for the support, i though ti was going to get flamed for suggesting such an idea. Sorry for my lack of knowledge for the fuel pumps in these cars but is that the stock turbo pump? Im going well over 300hp so i guess ill have to upgrade my injectors as well. Also just wondering...is the turbo pump the same as the n/a pump? I only have one turbo pump and the rest of them are n/a pumps. Do you know if the electrical could handle running two pumps if i just wired them in paralle? Quote Link to comment Share on other sites More sharing options...
mobythevan Posted March 15, 2004 Share Posted March 15, 2004 I knew I remembered sleeperz experimenting with two pumps, he encountered some issues though. http://hybridz.org/nuke/index.php?name=PNphpBB2&file=viewtopic&t=21168&highlight=check Quote Link to comment Share on other sites More sharing options...
Ben Posted March 15, 2004 Share Posted March 15, 2004 Re the 2-pump issues - staging the pumps can be a good idea (especially to limit fuel heating), but there may indeed be an issue with dampening of the output. I have seen many hi-po road cars running 2 & sometimes 3 Motorsport pumps in parallel. Most EFI race cars run at least 2 pumps, some as many as 4 or 6 (one low pressure for each high pressure). So it can be done & work well. Re: pump output. I do not know the specifications of the factory L28E or L28ET pumps. All I can tell you is that my N/A L24E pump is a nice quiet unit & 2 of them will provide plenty of flow for 400HP+. I will check out the free-flowing rate one of these days & post the results. There are equations that will tell you how much fuel flow you will need for a given HP-per-cylinder & how much flow will decrease with fuel pressure. If you have several working OEM pumps, then they are already cheaper than buying a new, noisy, overheating-the-fuel-when-demand-is-low pump. If you have issues with the multi-OEM setup then spend money! Quote Link to comment Share on other sites More sharing options...
Guest 79Datsun280zx Posted March 15, 2004 Share Posted March 15, 2004 I dont think id have issues so long as i can just wire the pumps in parallel. I have one turbo pump and two n/a pumps. Is there a difference between the pumps? I couldnt see one when i was comparing them. Anyway this is what i plan on doing. Making another line that comes from the take so that the flow from the tank will be more then enough. Then running a whole new line from the front to the back so that each pump has its own line from the tank to the engine. Ill run each line through its own fuel filter. Then im going to use a n/a fuel rail instead of a turbo one. The difference between the two is that the n/a has a cold start valve. This is where im going to connect my second fuel line. What do you guys think? Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted March 15, 2004 Share Posted March 15, 2004 The pumps I was plumbing in parallel were high pressure Bosch pumps. I don't know why they didn't play together, but judging by my fuel pressure gauge, there was no doubt they didn't like being plumbed inlet to inlet, outlet to outlet. Most likely they were starving for fuel, and separate inlets may have solved it. FWIW, the Porsche turbos use two high pressure pumps in series, just like the pump I was using. Of course, one pump is serving me just fine right now, but under higher boost pressure, plumbing pumps in series is a good solution for compensating for the high boost, maintaining fuel flow. Quote Link to comment Share on other sites More sharing options...
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