Help With Fuel Return Line Plumbing
Thread Starter
Instructor
Joined: Apr 2000
Posts: 165
Likes: 0
From: Vacaville California
Help With Fuel Return Line Plumbing
I'm installing 1/2" fuel supply line and wonder what size my fuel return line should be:
(450 hp 383, engine builder recommended 750 cfm Demon, Holly mechanical 110 gph pump)
*Note: I realize 1/2" supply line is overkill for the present engine, but someday I want more like 600 hp, in which people have told me a 3/8" line may not be enough, so I am installing 1/2" while I can, since the body's off.
1) Because the supply line is now larger than stock, should the return line also be proportionately larger than stock to maintain adequate return flow?
2) I want to keep the option open to switch to EFI someday, in which case I will have to have a return line of significant size to accommodate an electric pump (3/8" I've heard); with this in mind, would it harm anything to install a large return line now, though I will initially be using a carb?
3) I was thinking I'd simply use a "T" in the line just before the carb inlet and run my return off that; but would that be a good place to use a regulator? If I have a regulator I guess I also need a guage?
Any help much appreciated!
(450 hp 383, engine builder recommended 750 cfm Demon, Holly mechanical 110 gph pump)
*Note: I realize 1/2" supply line is overkill for the present engine, but someday I want more like 600 hp, in which people have told me a 3/8" line may not be enough, so I am installing 1/2" while I can, since the body's off.
1) Because the supply line is now larger than stock, should the return line also be proportionately larger than stock to maintain adequate return flow?
2) I want to keep the option open to switch to EFI someday, in which case I will have to have a return line of significant size to accommodate an electric pump (3/8" I've heard); with this in mind, would it harm anything to install a large return line now, though I will initially be using a carb?
3) I was thinking I'd simply use a "T" in the line just before the carb inlet and run my return off that; but would that be a good place to use a regulator? If I have a regulator I guess I also need a guage?
Any help much appreciated!
Melting Slicks
Joined: Oct 2001
Posts: 2,320
Likes: 2
From: Salem Oregon
On the 85 the stock return line is one size smaller then the fuel line, so that might be a good guide line. Also I was interested myself on the placement of the return line/ regulator hookups. Randy
Thread Starter
Instructor
Joined: Apr 2000
Posts: 165
Likes: 0
From: Vacaville California
AlwaysWave-
What are you using on the fuel line there to reflect heat? I've been keeping my eyes open for such material but haven't seen anything yet. What pressure do you set the regulator for?
What are you using on the fuel line there to reflect heat? I've been keeping my eyes open for such material but haven't seen anything yet. What pressure do you set the regulator for?
Le Mans Master
Joined: Feb 1999
Posts: 6,807
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From: Hoosier
Cruise-In III Veteran
Originally Posted by singedfur
AlwaysWave-
What are you using on the fuel line there to reflect heat? I've been keeping my eyes open for such material but haven't seen anything yet. What pressure do you set the regulator for?
What are you using on the fuel line there to reflect heat? I've been keeping my eyes open for such material but haven't seen anything yet. What pressure do you set the regulator for?
