Return line for fuel

[bearman]

Do you guys have a return fuel line to the tank if you do how is it done. Is the return to the top of fuel cell or not. is it the same size hose as input line. Does it get cooled down with a cooler. Or do you even need a return line. Maybe not on a all racer but should a double duty car have it with it being used on the street. Do you regulate incoming fuel before carb or regulate after carb on the return side.

 

[Sixpactogo]

Back in 1968, my brother and I bought new Chargers. Mine was an R/T with 440 and 4 speed. His was a 383 with 4 speed. His would vapor lock on hot days while mine never did. We finally figured out why. The 440 cars came with a 3/8" fuel line and 1/4" return line and the 383 cars had a 5/16" fuel line with no return. The 440 cars used a fuel sender with the 3/8 and 1/4" tubes built in and had a separator canister bolted to the fuel pump for the 1/4" return to the tank. The regulation was done at the separator before the carb. We ended up robbing the the lines, sender and separator from a wrecked R/T for his car and never had the vapor lock issue again. If you have a 383 car, you can buy the R/T equipment and upgrade easily.

 

[Mike Gaines]

On my Coronet I had a return style setup and then took it off. Made no difference in performance. The benefit of the return style line is to help COOL the fuel as unused fuel is sent back to the tank rather than dead heading at the end of the fuel system
My 3800 pound Coronet went 10.04 (even on 100 degree temperature days at the track) with a rather inexpensive (but new) BLACK Holley fuel pump, 5/16" steel fuel line from trunk mounted Fuel Pump (not 1/2 or 5/8 line) and NO Return Style Regulator...so...personally...I don't think you need one.

 

[threewood]

Yes, I have a return line on my GTX. I installed a Holley Sniper EFI tank setup w/ in tank 255lph Walbro pump (factory style tank) . I am running a 3/8" feed line to a return style regulator and a 3/8" return line to the tank. Regulator is before the carburetor. Edelbrock AVS2 carb. Very important!! If you are running a carb (6 psi regulated) do not use a smaller return line from the regulator as it will create more pressure past the regulator. I had 1/4" return line and it flooded the carb out. Swapped to 3/8" and rock steady 6 psi.

 

[Lionized]

Yes, I have a return line on my GTX. I installed a Holley Sniper EFI tank setup w/ in tank 255lph Walbro pump (factory style tank) . I am running a 3/8" feed line to a return style regulator and a 3/8" return line to the tank. Regulator is before the carburetor. Edelbrock AVS2 carb. Very important!! If you are running a carb (6 psi regulated) do not use a smaller return line from the regulator as it will create more pressure past the regulator. I had 1/4" return line and it flooded the carb out. Swapped to 3/8" and rock steady 6 psi.

Wait a second, are you running a carburetor or Holley Sniper? Your post is confusing.

 

[threewood]

Wait a second, are you running a carburetor or Holley Sniper? Your post is confusing.

I've got the EFI in tank pump setup. Not the EFI.

 

[cdr]

I have the EFI tank with a return, 3/8 supply, 3/8 return, it is carbed right now , without the return it would not run in the heat down here in Southeast Texas, stalling, vapor lock ect, works great now with a return set up, EFI is in the works now.

 

[erikcroissant]

I have the EFI tank with a return, 3/8 supply, 3/8 return, it is carbed right now , without the return it would not run in the heat down here in Southeast Texas, stalling, vapor lock ect, works great now with a return set up, EFI is in the works now.

Old thread but what are you running for the return line? I’m trying to find 3/8” hard return lines but can’t find any pre-bent.

 

[Sixpactogo]

The stock setup with 3/8" fuel line came with a 1/4" return line. No good reason to have a 3/8" return that I can think of. If you think you need it, I guess you could buy two 3/8 pre-bent fuel lines and use one for the return.

 

[biomedtechguy]

The stock setup with 3/8" fuel line came with a 1/4" return line. No good reason to have a 3/8" return that I can think of.

Agreed, my 70 V-code Roadrunner has the 3/8 fuel and 1/4 return setup, but I eliminated the vapor separator and plugged the return line when I switched to the Carter M6903 high volume mech fuel pump and Promax braided lines to the carbs. I am going to see what happens when I re-incorporate the vapor separator and connect it back to the return line. I think it may perform better, and stabilize and slightly reduce the fuel pressure from the Carter M6903.
This suggests otherwise:

If you are running a carb (6 psi regulated) do not use a smaller return line from the regulator as it will create more pressure past the regulator. I had 1/4" return line and it flooded the carb out. Swapped to 3/8" and rock steady 6 psi.

I don't have any fuel delivery or other fuel vapor lock issues with my 440 6bbl that I know of.
I thought only the 440 6bbl and 426 Hemi equipped cars had the larger diameter 3/8" fuel line, and I didn't know the 1/4 inch "vapor return" line wasn't on other 5/16 diameter fed setups...

 

[chtampa]

I think all cars are on the verge of vapor lock. I added a return line on one of my Runners and it barely helped. My final solution was a wood spacer under the carb. My current cars have a return line, EFI in-tank and I have no issues. What works for one car doesn't necessarily work for another. Remove all the variables when you have the chance and be happy if anything works. A return line does keep the fuel cooler. I installed fuel line heat wraps also. I added every fuel temperature isolation option I could think of and it all worked to save me.

 

[Dan64]

So I'm told from Carter's tech guy, If you are running a higher than stock fuel pump which needs a regulator make your return line the same size as the supply line, if not it can mess with the regulator. If you're running a mechanical fuel pump( like the strip super pump) don't use a return style regulator with a return line as the pump is designed to be deadheaded and bi-passed internally.

 

[erikcroissant]

The stock setup with 3/8" fuel line came with a 1/4" return line. No good reason to have a 3/8" return that I can think of. If you think you need it, I guess you could buy two 3/8 pre-bent fuel lines and use one for the return.

I’m running fuel injection that requires a 3/8” return

 

[matthon]

EFI, Wix filter/regulator with built in return, mounted near tank, one line up to engine.

 

[biomedtechguy]

Wix filter

ANY time I need a filter, if WIX makes it, WIX is the one I get.

 

[440rb]

Both the street/strip 340 Cuda I ran (2 blue pumps, 1/2" lines, 1 for N20.) were deadhead, no issues with the 850DP at all, the 440 Cuda race only car was exactly the same with same set up and no issues either with v/lock even at 1 of the meetings I can remember where it was so hot the sweat was pouring out my arms on the return road after making a run, both cars had open hood scoops.

 

[Budnicks]

with a bypass reg. & return line,
it keeps the fuel cooler & at an ample supply 'flowing'
helps the pump stay cooler 'usually' too

I've had them on every performance or racecar since 1977
what works you don't mess with it

I've had many that had -6 (3/8") in & -4 (1/4") returned, set flowing
or a -8 (1/2") in & a -6 (3/8") return
or a -10 with a -8 bypass with dual Dominators
all pressures 'set flowing'
I never had an issue ever
even on a 6bbl setup, in my car right now

done it on many tunnel-rams dual 4bbls or even 2/4 split dominators
even an old Barry Grant 350gpm or a CNC Pro 500gpm 16psi pump
in with a -12 feed & -10 (or even -8 returns into a y)
the carbs use what extra you'd think aren't flowing
or the needle & seats will shut when the car/engine demands
doesn't need it
lets the excess flow back to the tank
or where ever it's set to bypass
as much supply on-demand,
with no spikes or drops in pressures ever
(as long as the pressure isn't set too high, deadheading can/has cause issues)
I've done it for T/S or my Outlaw P/S 6.69 @ 217
or 7.90 S/E, or Pro-Gas 8.50 or S/C 8.90 or my 10.90 S/ST index
all since 1977,
even with 2 old Holley blues one for fuel other for N2O
& a Holley Bypass reg. on each

Mech. FI uses it, has several bypasses, of various sizes,
because it works

or any carb'd set up
'had a bypass style fuel regulated set up'
if you have the room or ports or means to do both the same size
by manufacturers & suppliers
then go that route, if it makes you feel better

IMO, It's mostly 'wives tales'