Rather than deadheading at the carburetor,I've been thinking about using the factory return line as a continuous circulating fuel system. Any pluses or minuses to this? The reason I've been thinking about this is my fuel pressure is all over the place set it at 9psi goes to 11psi,set back to 9 psi goes to 5-6 psi. I'm currently using a carter mechanical with a comp 140 back at the tank. I'm thinking that with a circulating system the fuel may stay cooler and the engine will only take what it needs as its circulating by. :confused:

any ideas? suggestions? Carter mech,Comp140 and regulator is what I have now.

Bob,
I run the big Carter mech pump and blocked off my return line when I installed it. My fuel pressure is rock steady at 8 psi. Maybe the issue is having the Comp 140 in series behind it??

Jim

Bob,

Is that the Carter 172 ? That is a 5/16 line correct? Probably won't make too much of a difference based on what a few have reported on this site when running small return lines.

I know Todd G had troubles with the return line not being large enough and he was using -8 with a Comp 250 though.

Have you made passes with just the mechanical lately?

My feeling is the same as Jim's..

Why two fuel pumps?

Bob,

This is the way I have my system setup.

I am running a Mallory 140 pump and filter at the tank with a welded in sump to the stock tank for the carb. #8 braided to the front where I am using a Holley max pressure regulator. In one of the pipe-to-AN fittings going to the carb, there is a 1/8" port (usually used for a gauge) but I installed an NOS (nitrous) flare jet fitting with a small nitrous jet connected to a #4 braided line going back to the tank. I am still playing with the jet size but someting around #30 seems to work pretty well. (Just enough to keep a small amount of fuel flowing during low demand times)

I have the same setup on the nitrous fuel system except for a Holley "Blue" pump.

I made the modifications late last year and only have about a month of driving it, but it seemed to work pretty well. The main reason I set my system up this way was for cooler, quieter and LONG life pump operation. In alot of city driving (i.e. alot of idling) my pump got pretty warm. Since the change the pump runs noticably cooler and quieter.

I will be experimenting with the system more this year.

Tom, 3/8" factory fuel line 8-AN from the mech. pump to the carb.,,,I made my first pass last saturday with just the mechanical,its a Carter strip version purchased thru jegs,,,the box is in the garage somewhere, anyway,,,my first pass,didnt turn on the electric pump and right at the 1000ft. mark it started cutting out,next pass I almost forgot again,turned it on after the 1-2 shift and no problems,and used it the rest of the day, 7 more passes total and no problems. As a matter of fact,I didnt even raise the hood the whole day,the only thing I wanted to do was jet it back down to see if some mph would come back but I forgot the jets :rolleyes:

hmmm....seems like it could have been a fuel issue. You probably know what I am going to say about the Carter 172. That's going to be my recommendation. ;)

But having the system already set up, where is the regulator? A return line can't hurt, where were you thinking of connecting the return line, at the fuel log or before the mechanical pump?

I was going to return off the back of the fuel log to the factory return line. The regulator is on the front of the fuel log.

Originally posted by 71454Chevelle:
Bob,

This is the way I have my system setup.

I am running a Mallory 140 pump and filter at the tank with a welded in sump to the stock tank for the carb. #8 braided to the front where I am using a Holley max pressure regulator. In one of the pipe-to-AN fittings going to the carb, there is a 1/8" port (usually used for a gauge) but I installed an NOS (nitrous) flare jet fitting with a small nitrous jet connected to a #4 braided line going back to the tank. I am still playing with the jet size but someting around #30 seems to work pretty well. (Just enough to keep a small amount of fuel flowing during low demand times)

I have the same setup on the nitrous fuel system except for a Holley "Blue" pump.

I made the modifications late last year and only have about a month of driving it, but it seemed to work pretty well. The main reason I set my system up this way was for cooler, quieter and LONG life pump operation. In alot of city driving (i.e. alot of idling) my pump got pretty warm. Since the change the pump runs noticably cooler and quieter.

I will be experimenting with the system more this year. That Mallory 140 pump, is it mech or elec? Not tryin to steal the show here, but, I'm in need of a better fuel system and would like to know more about your set up, and which fuel pumps are better for street/strip cars.

The Mallory pump is electric. I can drive the car fine with just the mechanical,but at those high demand times it comes up a little short.

Bob,

Sounds like you are putting 14 psi on the mechanical pump which is designed to suck fuel. Did you think of regulating it to 8 psi before the mechanical pump and using the internal regulating of the mechanical to keep 8 psi between the pump and the needle and seats. I am pretty sure the Carter Strip is a 7 to 8 psi., the 172 is.

LXS,

all you need is one of those 172 Carters. Keep it simple. That is all I use and running 125 mph+

Tom, I was having problems before I installed the Comp140,,,fuel pressure was erratic then,at first I thought it was the cheap holley regulator,so figured I'd kill two birds with one stone by getting the Comp with the regulator and just use the electric when racing. I installed the mallory regulator before I installed the pump,didnt help. I have an 2 5/8" autogage fuel pressure guage under the hood and I'm still getting erratic readings...I'm not sure what the carter is regulated at but I was getting readings of 11-13 psi. I've got a block off plate for the mechanical,was going to just use the Comp but I'd hate to be out and about and have the electric quit on me.