Feeding Inline EFI pump with Inline Carb fuel pump??
Thread Starter
Joined: Jul 2005
Posts: 2,119
Likes: 610
From: Henderson, TN
Feeding Inline EFI pump with Inline Carb fuel pump?? So Im ready to get my car back driving, previously had a carb and have since swapped to EFI.
Only thing I dont have is the fuel delivery to the engine. Since one of the problems I hear about with an inline EFI pump is they dont like to suck fuel from the tank I have considered just keeping the Carb fuel pump (Holley Blue pump) and using it to feed the high pressure pump so the high pressure pump doesn't have to suck from the tank. I could also mount it closer to the engine and reduce the amount of expensive EFI Fuel line I need to purchase.
So question is, has anyone done this or think this is a horrible idea? I plan to upgrade to a fuel cell with in tank pump when I go turbo but that will be a little while from now.
Only thing I dont have is the fuel delivery to the engine. Since one of the problems I hear about with an inline EFI pump is they dont like to suck fuel from the tank I have considered just keeping the Carb fuel pump (Holley Blue pump) and using it to feed the high pressure pump so the high pressure pump doesn't have to suck from the tank. I could also mount it closer to the engine and reduce the amount of expensive EFI Fuel line I need to purchase.
So question is, has anyone done this or think this is a horrible idea? I plan to upgrade to a fuel cell with in tank pump when I go turbo but that will be a little while from now.
Last edited by Ls7colorado; Jun 18, 2020 at 01:11 PM.
TECH Senior Member
Joined: Jun 2016
Posts: 22,295
Likes: 3,617
From: Central Cal.
Pumps move volume, not pressure, which is actually an indication of restriction.
What sort of pressure is the carb pump rated at?
If it can't handle pressure, then OK. But if it can, I would just use that.
What sort of pressure is the carb pump rated at?
If it can't handle pressure, then OK. But if it can, I would just use that.
Thread Starter
Joined: Jul 2005
Posts: 2,119
Likes: 610
From: Henderson, TN
I believe its max pressure is only 14psi, but Instead of just swapping it out with a high pressure pump Im talking about using it to feed/push fuel to the high pressure pump.
TECH Senior Member
Joined: Jun 2016
Posts: 22,295
Likes: 3,617
From: Central Cal.
Yeah, I guess I wasn't clear on that. Since it is only good for 14psi, I don't see a problem with using it for a prime/boost pump.
I have done just tgat a couple of times because if dusl tanks in old trucjs having a switch solenoid that's not capable of supporting efi pressures. I built large surge tanks that are top fed from the carb pumo and feed the efi from the bottom. Efi return is up top under the carb feed to swurl the fuel to de-aerate and at the top is a burp line back to the tank.
Here are 2 albuns showing how I did it
https://photos.app.goo.gl/jHFk5qNsw1JNWsyx8
https://goo.gl/photos/3aNmnwmnapgfMdK1A
Look for the pics of the surge tanks
Here are 2 albuns showing how I did it
https://photos.app.goo.gl/jHFk5qNsw1JNWsyx8
https://goo.gl/photos/3aNmnwmnapgfMdK1A
Look for the pics of the surge tanks
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9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
So Im ready to get my car back driving, previously had a carb and have since swapped to EFI.
Only thing I dont have is the fuel delivery to the engine. Since one of the problems I hear about with an inline EFI pump is they dont like to suck fuel from the tank I have considered just keeping the Carb fuel pump (Holley Blue pump) and using it to feed the high pressure pump so the high pressure pump doesn't have to suck from the tank. I could also mount it closer to the engine and reduce the amount of expensive EFI Fuel line I need to purchase.
So question is, has anyone done this or think this is a horrible idea? I plan to upgrade to a fuel cell with in tank pump when I go turbo but that will be a little while from now.
Only thing I dont have is the fuel delivery to the engine. Since one of the problems I hear about with an inline EFI pump is they dont like to suck fuel from the tank I have considered just keeping the Carb fuel pump (Holley Blue pump) and using it to feed the high pressure pump so the high pressure pump doesn't have to suck from the tank. I could also mount it closer to the engine and reduce the amount of expensive EFI Fuel line I need to purchase.
So question is, has anyone done this or think this is a horrible idea? I plan to upgrade to a fuel cell with in tank pump when I go turbo but that will be a little while from now.
As long as the EFI pump always flows less fuel than the carb pump...then potentially it could be ok.
However, it doesnt resolve the issue of fuel slosh in the tank, which a carb setup can get away with a little bit because the carb itself has a reservoir of fuel...but EFI cars do not tolerate an interruption of the fuel supply
The efi pump can flow may more if it recirculates back to the surge tank. A carb pump of dexent size will easily supply more fuel to the surge than. THE ENGINE CONSUMES. Thats what you need to keep adding to maintain a full surge tank
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
The lift pump may require less capacity if a surge tank is used and the main engine return goes back to that surge tank. Which is a different thing.
But he hasn't stated he wants to use a surge tank, although it would be the correct thing to do here, and done right would negate the need for a custom fuel cell.