Benefits of a return fuel line?

[cudaken]

So what are the benefits of a return fuel line? Fuel injection I understand. I have ran an Hemi fuel pump in my 68 Road Runner with no problems. Holley blue pump with no return line as well. 70 Cuda 383 with a small Carter Fuel pump and all so no return line. 

Is it a smog thing, makes the pump last longer? I normally get 40,000 miles plus out of a pump. Heck, I usually replaces them because I change something in the motor and need a different pump than have one fail. 

Cuda Ken 

[squeakfinder]

              Are you bored or something? It must be a pressure relief of some kind.



       By the way, thanks for your help on my projects..

[cudaken]

              Are you bored or something? It must be a pressure relief of some kind.



       By the way, thanks for your help on my projects..

As far as the pressure relief, stock HP 383 did not have one?
Far as any help I may have given you, you are more than welcome! 

Ken

[myk]

I'll be listening in on this thread.  I recently disconnected/plugged off my vapor return line because I was told the high-RPM-cutting out issue I had was caused by fuel pressure being bled off by the filter and the vapor return line; the electric fuel pump couldn't compensate properly.  Turns out the pump was the problem but I don't know if disconnecting the vapor return helped out or not. 

I was always under the impression that vapor return lines helped with vapor lock?  At the very least they allow some fuel to be sent back to the tank as opposed to just evaporating into thin air; that's a good thing, right?  Let's hear some opinions...

[cdr]

what myk said,,,,it helps keep the fuel cooler & prevent vapor lock,also on an electric pump it helps the pump run cooler thus last longer,i always use a fuel return fuel system on cars i build,it is also a more efficient & BETTER way to control fuel pressure at a carburetor & a must with fuel injection. there are dead head fuel injection set ups but i wont get into the problems they are having with them other than electric pump life is shorter.

[myk]

what myk said,,,,it helps keep the fuel cooler & prevent vapor lock,also on an electric pump it helps the pump run cooler thus last longer,i always use a fuel return fuel system on cars i build,it is also a more efficient & BETTER way to control fuel pressure at a carburetor & a must with fuel injection. there are dead head fuel injection set ups but i wont get into the problems they are having with them other than electric pump life is shorter.

Wow good stuff, I need to reinstall that 3-way filter ASAP.  Is there a certain type I should use?  Or will any 3-way fuel filter (1 inlet, 2 outlet) work?

[Dino]

what myk said,,,,it helps keep the fuel cooler & prevent vapor lock,also on an electric pump it helps the pump run cooler thus last longer,i always use a fuel return fuel system on cars i build,it is also a more efficient & BETTER way to control fuel pressure at a carburetor & a must with fuel injection. there are dead head fuel injection set ups but i wont get into the problems they are having with them other than electric pump life is shorter.

Wow good stuff, I need to reinstall that 3-way filter ASAP.  Is there a certain type I should use?  Or will any 3-way fuel filter (1 inlet, 2 outlet) work?

Tadaa!

http://www.megapartsusa.com/proddetail.asp?prod=216%2DV03

[maxwellwedge]

Just some things to watch out for.....

There were some bad ones out there where the pipes inside were reversed as to the lengths they should be. Anything over an idle would have the "running out of fuel" effect. Hopefully these inferior units have cycled out of the market by now.

Also - the orifice on the return line nipple is way too big on some of these repo's.....causing too much bleed off of fuel back to through the return line. There is a pic of the vap sep in the FSM.....if I remember correctly the factory orifice should be around .060"

[cudaken]

Lets say I go with the return line, where would that funny looking filter go?

Cuda Ken

[myk]

Lets say I go with the return line, where would that funny looking filter go?

Cuda Ken

You mean the stock one that Dino posted?  It hugs the block and is mounted somewhere up front; I forget where I put mine...

[Dino]

The filter is bolted to one of the mechanical fuel pump bolts.

[squeakfinder]

     Down stream from the fuel pump. In other words, between the pump and carb. Allthough I've mounted filters between the gas tank and pump. Seems that's not the Kosher location because of the risk of a filter coming apart and getting sucked into the pump.

[Dino]

Let me rephrase that, the 'filter' I posted is a vapor separator.  The other stock filter is the sock in the tank.  You can stick an additional filter between pump and carb or even between tank and pump.  It is true that it could kill the pump, but I'd rather replace the $25 pump than to have junk go down the carb.  Either way is bad, it's just a question of what is the lesser damage.