Fuel delivery options for EFI?

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Theduke
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Fuel delivery options for EFI?

Post by Theduke »

I've read alot and want some opinions regarding best way to deliver fuel to a EFI setup.
I have read that in tank is preferable to a in-line setup because the submersion in fuel keeps it cooler and quieter. Makes sense to me. I've also read tons of posts about FSJs lack of baffles in the tanks and issues of sloshing and fuel starvation when lower than 1/4 tank.
I contacted bjsoffroad since they sell in-tank and sump pump units and they said for proflo4 to use the edlebrock sump pump option, but their q/a for their in tank says its great for a sniper tbi. So I don't know why the answer isn't consistent.
Also I honestly don't know why you'd want to double the amount of parts in a fuel system by having an electric pump in the sump for high pressure to efi but also a mechanical pump for low pressure feeding the sump.
I am deciding between a sniper and a proflo4 but would like a better understanding of the fuel delivery options apart from the EFI choice.
Thanks
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89_Wagon
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Re: Fuel delivery options for EFI?

Post by 89_Wagon »

Not sure why they have 2 pumps, but I don't think electric pumps like to pull fuel. They are best at pushing it.

Regarding fuel pump setup with efi, I first tried an external pump on the stock gas tank and had starvation problems at half a tank, especially while turning. That probably has more to do with the pickup tube. Very noisy too. The next setup was a s10 2 door blazer gas tank and pump. No issues at all. Getting the filler neck to work was the hardest part but definitely doable. I lost my spare tire area but the stock saddle tank causes major rust on the frame anyways. Overall, I consider it a win.

Also, keep in my mind the fuel pressure regulator determines the fuel pressure in the EFI system, not the pump. So a 50 psi pump on a system with a 12 psi regulator will only put out 12 psi.

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Re: Fuel delivery options for EFI?

Post by sirrus »

I used Edelbrock sump with PF4 and so far it works great, however I haven't driven it yet :) Mounts great under the coolant overflow bottle, very quiet and has built in pressure regulator with a vacuum reference. Last part is important for port injection like PF4, TBI systems do not care about differential fuel pressure. Another option that I was looking at was RobbMC surge tank, but it's bigger, hard to mount (unless you're throwing charcoal canister away) and requires external pressure regulator.

I chose sump over in-tank pump because I didn't want to mess with dropping factory tank (I'm working on my Jeep in the parking lot) and lack of baffles in that tank. Installing s10 tank wasn't an option for me because of the 1st reason, and Id like to have a spare tire (even if it's a total PITA to get it out :)). In general, having a baffled tank with a submersed pump in it the the best solution for EFI
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Stuka
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Re: Fuel delivery options for EFI?

Post by Stuka »

One the reason for dual pumps is so that you don't have to modify the tank. You use the mechanical pump to fill a surge tank, and then the electric pump to up the pressure to whatever level the EFI system wants.

In higher power cars it tends to be so the pump back in the tank doesn't have to be super high volume to feed the engine. The surge tank will allow for high fuel flow for a short period of time.
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