return fuel line

[LuckyWinner]

when do you and when dont you use the return fuel line system? Im going to run a 347 with carb. Do I need to run a return line?

[Gordon Levy]

It depends on the size of your fuel system and the pump you use. Pumps for carbs that can feel up to around 180gph and 600hp usually have an internal bypass. Fuel pumps that are larger like 220gph and larger have a return line to bleed off excess fuel. For your engine choice you don't need a bypass fuel pump.

[efnfast]

Like Gordon said - the pump will dictate it in a carb setup. Some pumps (e.g., holley billet) will let you deadhead the regulator (no return line) others like an aermotive a1000 will require a return line.

[ram_g]

THIS DOES NOT APPLY TO YOUR SITUATION but just posting this information here in case somebody does a search...:cool:

4.6 modular engines up to 1998 use a return type fuel system with a pressure regulator on the fuel rail determining the volume sent back. 1999+ modular engines use a return-less fuel system with a Fuel Pump Driver Module, i.e. a specific computer chip, located in the back driving the fuel pump.

Modular crate engines from Ford of any year use a return type fuel system because the harness supplied with the crate engine does not include the FPDM.

[riptide motorsport]

You won the kit so Im not sure what the mkiv tank is or the pump is but if your using an in tank fuel pump you run it up to a bypass regulator and a return line..........HTH steven

[BigLeo69]

no return on my carb/fuel set-up external pump blue holley, regulator in at the bottom and out the side to carb, held to the specs for psi didn't even adjust it.

[JGPierce]

Newer Ford Mustangs with return, but with pressure regulator. The Ford Racing Harness won't work without it.

[Fifty-Two]

Never hurts to run a return line ...
With a carb, you can run a bypass-style regulator (i.e, Mallory #4309) with a return line - this will help avoid vapor lock issues. And, if you want to switch over to fuel injection in the future, since you already have a return line the transition should be fairly easy.

- John

[LuckyWinner]

THIS DOES NOT APPLY TO YOUR SITUATION but just posting this information here in case somebody does a search...:cool:


Modular crate engines from Ford of any year use a return type fuel system because the harness supplied with the crate engine does not include the FPDM.

Im getting a Fordracing engine from Gordon, would I use a return system? Every post says I wouldnt with my set up, but this post about Modular crate engines from Ford has me confused

[Fifty-Two]

Im getting a Fordracing engine from Gordon, would I use a return system? Every post says I wouldnt with my set up, but this post about Modular crate engines from Ford has me confused

I think Gordon's post earlier in the thread should be your best guide. If the engine is from him, he will know best for your specific situation.

And congrats on your big win! :D

[LuckyWinner]

I think Gordon's post earlier in the thread should be your best guide. If the engine is from him, he will know best for your specific situation.

And congrats on your big win! :D

WOW....not Gordon, Mike Forte, my bad. Although Gordon makes a very nice engine!!!!!

[Xybram]

If you are going with a carb you then have 3 options.
1) Mechanical fuel pump - This only requires a supply line (Tried and True method and good up to 500 hp)
2) Dead head electric - This also only requires a supply line
3) Bypass electric - This requires a return line

The choice is up to you.

With the single line you will want to get the carb tank fitting from Breeze.

With an electric pump you will want to set up a shutoff for the pump should you get into an accident. Not hard to do.

My vote is to go for simplicity. The mechanical pump.

Chris

[MHCobra]

My mechanical pump works great! Simple!

Mike