external fuel pump
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Will the Holley P/N 12-920 support the LS1? Holley says it will. Literature says it is 67gph at 45PSI!! Is it capable of 58PSI? Has anyone used it. Looking for something less than $300 Aeromotive solution.
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I don't think it will flow enough. Especially on a fuel injected motor where you'd like to have a safety margin (lean is bad). I'm partial to Aeromotive pumps though. I've been finding all the formulas I can to figure out fuel line size, required pump capacities, and injector sizes and here's a little of what I've learned. BSFC X PEAK HP= lbs/hr. Most people use a BSFC of .45 for NA engines but some use .50 (I use .50 for a safety margin). For forced induction/nitrous use a BSFC of .55. So for a 400hp engine we'll need 200 (180 for .45 BSFC) lbs/hr. Now we can figure out injector sizing. This formula is lbs/hr=(BHP X BSFC)/(# of injectors X duty cycle). So for a 400hp engine, a BSFC of .50, 8 injectors and a 80% duty cycle would require an injector flowing 31.25 lbs/hr. Keep in mind most injectors are rated at 43.5psi. On our LS1's we need 58psi (hence using SVO injectors: availability, price, and higher flow rate at our pressure). A injector rated at 30lbs/hr (43.5psi) would flow 35.23lbs/hr at 60psi. A safety margin plus a little room for later upgrades. (Note the previous formula figures at what hp level an injector will support at 80% duty cycle, so 400hp would be max.) As far as line size and gallons per/hour we already figured out we needed 200lbs/hr. Divide this by 6 (gas-weight per gallon) and we get 33.33GPH. To support a 550hp engine with 1/2" (-08) fuel lines at 46psi, we need a pump capable of 127GPH free flow. For a 350hp engine with 3/8" (-06) fuel lines at 29psi, we'd need a pump capable of 81GPH free flow. I don't think the Holley could maintain the volume nor pressure required for an LS1. The A1000 Aeromotive pump is rated at 500lbs/hr at 45psi. Even the little 11106 is 360lbs/hr at 45psi. Of course this is all in theory. Real world could be different. Hope this helps.