Return Line?
Thread Starter
Racer
Joined: Jan 2014
Posts: 425
Likes: 3
From: Jefferson City Missouri
Return Line?
I noticed today that it looks like I have a fuel return line that is not being used. There is a second line along the passenger side frame rail that goes all the way up to the fuel pump. It's blocked off.
This is on a '68, did they have a return line on them? Can this be used with a electric fuel pump for a FI system?
This is on a '68, did they have a return line on them? Can this be used with a electric fuel pump for a FI system?
Burning Brakes
Joined: Mar 2014
Posts: 904
Likes: 46
From: Crestline CA
In 68 all quadrajet equipped cars had a return line. I suppose you could use it as a return line, only problems I can see is the size of the line and the potential for splashing noise of the fuel returning to the tank.
Burning Brakes
Joined: Sep 2006
Posts: 1,071
Likes: 86
From: Rotonda FL
Check the size(s) of the two lines. On later years, the supply line is 3/8 while the return is 5/16. The 5/16 has substantially less sectional area (flow) than a 3/8, and is not normally used in any performance worl.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
YES and NO....it depends on a lot of the type of fuel pump (in tank or external...and if external...the manufacturer of the pump)....pressures needed for the Fuel Injection system you are using. Many variables that come into 'play' here so it can not be an easy question to answer without knowing what is being used.
DUB
Thread Starter
Racer
Joined: Jan 2014
Posts: 425
Likes: 3
From: Jefferson City Missouri
Those sizes seem about right. Although I haven't actually measured them, I'd be surprised if there were anything but.
Thread Starter
Racer
Joined: Jan 2014
Posts: 425
Likes: 3
From: Jefferson City Missouri
YES and NO....it depends on a lot of the type of fuel pump (in tank or external...and if external...the manufacturer of the pump)....pressures needed for the Fuel Injection system you are using. Many variables that come into 'play' here so it can not be an easy question to answer without knowing what is being used.
DUB
DUB
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
If there are no major drawbacks to the external pump, I wouldn't mind going that route. I don't plan to have a huge build, but it is a 454 and could use some fuel. I was thinking about using the EFI 2.0 possibly with the direct injection. Will that require higher pressures then the throttle body injection?
With that written.,..I would have to assume that if going from throttle bodies to another injection system...I would assume that the pressure would have to be increased.
DUB
Burning Brakes
Joined: Oct 2008
Posts: 1,037
Likes: 14
From: Mobile Alabama
+1 with everything DUB said.
I like in tank pumps for injection, but many use external with no problems. Decide your injection system first, as most all have different pressure needs. Then you can look at your pump and how you will regulate it. That will dictate what your return should be.
I like in tank pumps for injection, but many use external with no problems. Decide your injection system first, as most all have different pressure needs. Then you can look at your pump and how you will regulate it. That will dictate what your return should be.
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