Return fuel system w/ current parts?

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Cudafever

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This is for my 408.
Electric fuel pump. similar to this http://www.summitracing.com/parts/crt-p4594 BUT its a lift pump out of a dodge diesel (20 psi pump)

And a mechanical pump similar to this http://www.summitracing.com/parts/edl-1720/overview/year/1970/make/plymouth/model/barracuda
My pump is the carter super pump that was sold from MPP.

I want to make a full fuel return system this is how its set up now.

Installed a return bung in the tank, bolted the electric pump on frame next to fuel tank, fuel regulator next to that, fuel return back to tank, and feed line up to mechanical pump, and dead headed at carb.
Regulator set a 5 psi pushing on mechanical pump, carb pressure at 9 psi.

By moving the regulator to the eng compartment, past the carb (how it should be) i worry that 9 psi on the suction side of the mechanical pump will be to much for it.

As i type this, and ponder on how a mechanical pump works, i thing i have already answer my own question. But i will post it up any ways. Would like all your though as i my be way off base!
 
I don't know why you don't just dump the mechanical pump and be done with.

If that thing ruptures a diaphragm and fills the pan with gas.......................

For me, a front orifice / regulator return system is great for preventing boiling / vapor lock. First one of these I ever saw was my old 6bbl 70 RR.
 
Well i would hope that it would leak out of the vent hole, but that is something i had not thought about, thanks

I just don't know if the electric has enough volume to keep up the pace.
Elec = 50 GPH Mechanical =110 GPH. Mechanical will vapor lock, electric my run out of fuel on the top end.

It don't "vapor lock" trying to Start......it happen about 60-80 feet out, but only when it had a good heat soak in the middle of the summer. when i added the electric pump, problem when away.

The combo works, so i want to us it.......but i may have to give up one or the other in the end.
 
I thought about starting a new thread but this has all the info and is going down the same road.

What i would like to see is some pictures (descriptions work too) of how you routed your fuel return line form the carb, out of the eng bay. How you plumbed you pressure regulator, exc.
 
I was under the impression that lift pumps were not very high volume. Do you have a GPH spec for it? For any kind of HP gas system, you need around or over 100 GPH.
 
50 gph 1/4 NPT In/Out. That pump is not considered high performance in a diesel application, as it was meant to be a replacement for the weaker stock lift pumps on the older dodge trucks(99-04). I'd have to agree, ditch the mechanical, and get a real electric pump for your setup. Do you really see 20psi out of that pump? Typically its under 15psi.
 
FredS said:
50 gph 1/4 NPT In/Out. That pump is not considered high performance in a diesel application, as it was meant to be a replacement for the weaker stock lift pumps on the older dodge trucks(99-04). I'd have to agree, ditch the mechanical, and get a real electric pump for your setup. Do you really see 20psi out of that pump? Typically its under 15psi.
Click to expand...

LOL I was a dodge diesel mechanic for many a years yes, they were replaced like candy. I have a large card board box full of them. this was one of the better ones.

A trick with these pumps was to take the three screws out of the top and flip the lid over. Clean the screen,new clean surface for the top of the vanes to run on.

this one was one that was replaced and then replace with a WALBRO after market frame mounted pump.

To answer your question, no i didn't test the max pressure. installed it, feed it to a regulator to push 5 psi so the mechanical pump didn't have to pull fuel. It worked.

Now i want to move the return fuel regulator from next to the tank to the eng compartment so the fuel no longer dead ends at the carb.

NHRA don't allow on the fire wall and i just don't like the look of a fexable fuel line returning over the Valve Cover.........
 
RustyRatRod said:
That's not a ton. But I guess if it works....
Click to expand...


It only works because it is regulated to push 5 psi to the suction side of my mechanical pump up front, that's rated at 110 gpa. This was done for fuel vapor reasons only.
 
Was it me, oh wait it sorta was, I'd ditch the P4070 variant and the mechanical pump both. Replace them with something like this: http://www.summitracing.com/parts/vpn-gsl392bx/overview/ Run your choice of by-passing regulator in the engine bay. Run a new 3/8" supply line and use the original supply line for the return line.

'65 Valiant-
Pump location:
i-ggtF8QF-M.jpg


Regulator location:
i-qvCkXjQ-L.jpg


Now that I'm not running the Mopar IGN module I wish that I had made a plate that replaced the module for the regulator to bolt to.
 
Nice price on the Walbro!
think i will pass on the regulator. Already have one, don't have any boost to justify that price on that one.


I was hoping to have some good pic on how every body routed there fuel line/ return lines, under the hood............

I just don't like the look or the idea of running a fuel line(fuel return) over the valve cover. I thing i will be making a u turn at the carb and run it back down in front of the motor, like it is fed now. Then have the regulator mounted on the fender well, were the return line will go back to the tank

Mmmm i guess i could have the regulator on the fender and then dead head it at the carb.
Just think it would work better if the fuel was going past the carb and then getting regulated.
 
Which way to plumb it can depend on how the regulator is designed. Some can be plumbed either way, others have a decided preference for one vs. the other plumbing method.

Mine has about 20" of dead-headed hose btwn the regulator & the carb. If vapor lock were a huge problem I'd move the regulator much, much closer to the carb. As long as I don't buy the cheap junk and ARCO fuel all is good.
 
Also, if you need a pressure gauge I highly recommend the Autometer (Autogage) 2172. It's liquid filled but has a pressure release so it reads steady and doesn't have the issues of changing it's reading as temp goes up. Simply open the pressure relief and it reads accurately every time. Best gauge I've ever owned and I've owned several, both liquid and non liquid filled.

http://www.autometer.com/pressure-gauge-0-15-psi-sport-comp.html
 
I've used one of these in the past:
http://www.mcmaster.com/#3850k3/=y3afhf $24 as of 07/17/15

3850k31p1-c02cl.png


Hard to go wrong with either a genuine Bosch 044 or a genuine Walbro GSL 39X. It's the counterfeits that suck, and they're easy to end up with unintentionally. Best protection, though no guarantee, is to buy from a reputable vendor.
 
I runy fuel just.like.the above pick but my.regulator.is behind the carb.
this way my.pressure reg is behind the floats.

The fuel reg with a stock pump dont need to be infornt in fact some folks starve fuel like that. with my fuel reg in front of the floats i did have vapror lock.
moved the reg to behind the floats and no more vapor lock.

my .02
 
Cope said:
I runy fuel just.like.the above pick but my.regulator.is behind the carb.
this way my.pressure reg is behind the floats.

The fuel reg with a stock pump dont need to be infornt in fact some folks starve fuel like that. with my fuel reg in front of the floats i did have vapror lock.
moved the reg to behind the floats and no more vapor lock.

my .02
Click to expand...

In that pic, it looks like a dead head system. Not return system. that's why i was asking UOP for some clarification. can't see how it returns????
 
Looks to me like supply is at the rear of the fuel manifold, regulator obviously at the front, with return out the bottom of the regulator. Could be wrong, but I *think* that I see a hose with a 90° hose end on it coming into the rear of the manifold.
 
finally getting around to this project. Had to test my currant electric fuel pump(aka dodge diesel lift pump) to compare when i put my new pump in.

its a 50 GPH pump. Hmmm @ "0" psi, it 240 GPH pump, at only 4 psi (What i had my regulator set at) its a 54 GPH.

Now to drop the fuel tank, mount, my new pump and bend some new 3/8 fuel line up to the fender.
 
OK just to put a period on this thread.
I when with new 3/8 fuel line, installed this fuel pump http://www.gsl392.com/ us a 4 port regulator and the stock 5/16 fuel line as a return. End up flowing around 80 gph at 4 and at 9 psi.(pump is designed for much more pressure than this.)

End up mounting the regulator on the fender and braided stainless over the valve covers to the carb.

This pump is so quit that you can hardly here it with the insulated sleeve that came with it.

Took it to our local 1/8 mile track and test the fuel pressure with a gauge on the wind shield. Never moved from 9psi all the way down the track. Marked out a 1/4 mile on a back road and at 6800 rpm it still held at 9psi.(normally shift at 5800 rpm)

Real happy with the hole new setup!
 
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