My race 289 with stock dual 660's would suck the bowls dry on the big end. We crossed at 8000 rpm and were feeding the carbs with a Mallory 140 and a 1/2" line. BG 280 took care of the problem.
My motors not going to be a race motor. Its just a 302 GT-40X create motor. 345 hp 310 ftlbs trq. I just need to know what what flow rating i will need from the pump. Also, will a mechanical fuel pump work well with this engine?
Mike
Sorry to be a supergeek and wreck all your work, but is the A/F ratio by mass or by mols of substance? I'd think it would be 14.7 mols of air for every mol of fuel, and so unless air and fuel specific weights are the same, your 14.7lb air to 1lb gas won't be correct. I'm not sure if the A/F ratio is by mass or not though...
Sorry to be a supergeek and wreck all your work, but is the A/F ratio by mass or by mols of substance? I'd think it would be 14.7 mols of air for every mol of fuel, and so unless air and fuel specific weights are the same, your 14.7lb air to 1lb gas won't be correct. I'm not sure if the A/F ratio is by mass or not though...
I did look it up on several sources before posting. Also, I got a similar answer to 6T6coupe, so unless I made two mistakes ...
I'm not sure what a mol is - do you mean molecule? Or mole? A molecule of gasoline, if you assume octane approximates gasoline - has 8 carbon atoms and 18 hydrogens. Air is a mixture, not a molecule, but roughly 20% of its composition is O2. The products of "good" combustion are carbon dioxide and water. So you need 16+9 = 25 oxygen atoms to burn a molecule of gasoline.
I'm not feeling up to doing the calculations to back this up, but that's the information you need to do it. You'd have to look up the density of air and gasoline to get the relationship between mass and volume.
As for mol, I just looked it up and I was using it incorrectly, it too means the weight of a substance. What I meant was say for every number of molecules of fuel, you might need 10 times that amount of seperate 'pieces' of air. (As air consists not only of Oxygen molecules, but Ozone and Nitrogen, etc.)
Anyway, it is irrelevant now, as you were correct! I thought your answer looked good in the first place.
Here's an update to the initial question as to whether a 100 gph pump will support a 500 hp motor------- As some of you may know I just recently swapped in a 331 stroker motor into my 89 Ranger. This motor should by all accounts be putting out an honest 450 hp. It's built with a 10.4 to 1 comp ratio, Ford Z303 roller cam with 1.7 rockers to increase the lift, Canfield heads with 1.94/1.60 valves, 57cc chambers. The intake is a repro of the Ford/Holley 3x2 setup sold thru the dealers in the 60's and 70's. All three carbs are 250 cfm 2 bbls with 60 jets in the primary carb and 62's in the secondaries. My fuel pump is an "el-cheapo" parts house special, Purolator 30 gph elec low pressure pump feeding 3/8 fuel lines, from the tank to the carbs. Even at wide open throttle for upwards of several minutes, it has yet to fail to keep the three Holleys fed. So yes I still feel a 100 gph pump is way overkill for a 500 hp motor.