Thread: Fuel return line

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I've seen many different ways to go about this but what works the best? I'm putting a fue lcell into the K5 right now. My setup right now is electric fuel pump to holley regulator then to 750dp.

I've ran the return line from the regulator to the fuel tank on the couple of carb'd engines I've had when I had an electric fuel pump on them.

no return line on my pinto or stang .. just a vented cap ..

So what style of FPR did you buy? Some simply close off at the set pressure, backing the pump up on it's curve, while others bleed off excess pressure to a return line, capable of flowing rated flow of the pump, like at idle & cruise. Putting in a fuel cell doesn't mean you have to add a return line, right? The need for the return line is determined by the FPR, I believe.

Its a holley regulator. Also i've seen some setups that have the one line going in then both outlets are going to each bowl of a dp? Is that setup better or just have one inlet to the carb....

Yeah, I read that it's a Holley regulator in the first post, but which one? Holley makes a whole bunch of different regulators, and some are "bypass" type which have to run a return line to the tank (most of their EFI line are bypass type), and some are simple regulators that choke down at the set pressure, backing the pump on it's curve. It sounds like you don't have a bypass type, so you cannot run a return line.

Originally Posted by Hoss Blazer

I've seen many different ways to go about this but what works the best? I'm putting a fue lcell into the K5 right now. My setup right now is electric fuel pump to holley regulator then to 750dp.

I can't wait until my chance to use one of these. Toooooooo slick!!!
Mallory brand | Part #: 4302M


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Originally Posted by techinspector1

I can't wait until my chance to use one of these. Toooooooo slick!!!
Mallory brand | Part #: 4302M


.

for that kind of bucks they should come out and install it. hahaha

A Holley Red pump does not use a return. It is factory set around 6 lbs(?)
Holley Blue, Black, & EFI REQUIRE a return due to excess of 14 + lbs up to whatever the EFI uses---- The EFI needs to be regulated to injector requirements & a return must be used.

What pump is being used?

Originally Posted by t-top havoc

A Holley Red pump does not use a return. It is factory set around 6 lbs(?)
Holley Blue, Black, & EFI REQUIRE a return due to excess of 14 + lbs up to whatever the EFI uses---- The EFI needs to be regulated to injector requirements & a return must be used.

What pump is being used?

I found out the hard way that you had to have a return on a holley black. I just had the standard regulator and used the bottom port for return if I remember correctly. One side was feed into the reg, the other went to the carb at the fuel line that feeds the bowls.

Its fun to watch the vents spew like a fountain!! : '-(

Hoss Blazer--
Sorry for the late Q--
Do you know the Gallons Per Hour & free- flow rate?