Fuel Pump Upgrade

[Shane@DBPerformance]

Most of the old school fuel math you see on the internet and in books doesn't even work right for pump gas/race gas let alone E85. If you go by some of that stuff, you would need 1000000000000000000000cc injectors and -16 fuel lines(I am exaggerating, but...)
Also the math to figure additional fuel needs for injector and fuel pumps are different. Fuel pumps are not hit nearly as hard by running E85 as injectors are.

[Halon]

Its stupid upgrading your fuel pump, a fuel pump is designed to provide 3 times the capacity of what it calls for. I dont think Ive ever or will ever see a car on the street or street/track car that will need to upgrade its fuel pump.


First off I'll say like everyone else did. In a boosted application like ours, and where we run what'd i'd consider a good amount of boost in our cars often, you have to run the pump in a higher pressure range where the pumps are typically less effecient. At a base fuel pressure of 40psi, a pump will flow a good amount of fuel, and hence the reason people cometimes say if you have a 255 pump in your car, you may start to overrun the stock FPR at idle, but it doesn't matter once you start driving around. So now say you are running 20psi, you're fuel pressure just went from 40 to 60. Look at those charts and see how much less that pump flows.

Also for fun, I quoted you above. You could ask him "well what if you're planning to make 3 times the power?" :D

[Halon]

Fuel pumps are not hit nearly as hard by running E85 as injectors are.

I've heard that before also. Acually I think I heard it from you in a thread over on the Supraforums. Does anyone know why exactly that is?

[Alpha D]

Interesting. So using the formulas above might not be the best way of calculating the rate of flow ect? Im trying to find a side by side graph or something along those lines to see a comparison with the same variables referring to injectors, FPR, lines, Turbo set up or displacement of a N/A and so on.

[Alpha D]

Halon i did! In addition to E85 and giggled . . .and of course everyone looks at the dsm kid funny . . .haha. Yet his comment about any street/track car not being able to use the pump to its max just seemed odd to me.

[mlomker]

Most of the old school fuel math you see on the internet and in books doesn't even work right for pump gas/race gas let alone E85.

I was even surprised by the link that I posted. I was under the impression that it was around 30% more flow and not anything like 48%.

[Halon]

well, i suppose you could drop your base fuel pressure to like 10psi, so then at 20psi of boost you'd be at 30psi of fuel pressure :) No idea if the injectors would like that though, and you're idle, wellll that'd suck pretty bad I bet.

[Alpha D]

10psi. . .the Honda we worked on yesterday we put a inline resistor in the fuel pump circuit when enough resistance was added to bring the pressure down to 15 stuff start going bad it kills at 10 psi . . .now automatically i think its gonna be WORST on a DSM haha just cause its a DSM lol!

[Matt D.]

Keep in mind that our fuel pressure regulators are rising rate on a 1:1 scale. For every PSI of boost the engine sees the fuel pressure goes up 1 PSI. Like Shane said, that's where our stock pumps become inefficient.

[Alpha D]

Keep in mind that our fuel pressure regulators are rising rate on a 1:1 scale. For every PSI of boost the engine sees the fuel pressure goes up 1 PSI. Like Shane said, that's where our stock pumps become inefficient.


It does that would mean. . .for the guys at 30psi plus there FP goes up to upwards up 70PSI? That is serious pressure. . .technically according to his analogy that still wouldn't be enough to render the pump useless since even under hard acceleration the pump only uses 1/3 of its capability meaning at 40-47psi random honda spec. . .120PSI would be needed to max out the pump. Thats just ridicules i dont care what he says 120psi to max a stock pump that dosnt even make any sense.