Plumbing a fuel system

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Illahe

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Looking for product/style recommendation for plumbing a fuel system. I run a small tank that had a 10an system from the previous owners alcohol set up. There seem to be a lot of knock off garbage and I'm not opposed to bending up some 1/2" aluminum tubing.

Fuel system feed two Holley's and 12.5:1 414 ci small block. I realize there are a lot of "opinions," yet I'm looking for feedback from members that have had success at the track vs. the keyboard. Pictures would be appreciated!
 
Whatever you do, plumb the system for return line and use it.

Buy a QUALITY return style regulator. The big Mallory 4 port was the best but you can only find them used any more. I have one.

With the pumps you have you can probably use the smaller Mallory bypass regulator and be fine.

No smaller than -10 from the tank to the pump(s). These pumps are designed to push, not suck. So any restriction to the pump(s) is bad. -12 is better if you are nearing 800 hp or more.

No smaller than -8 from the pump to the carb(s). -10 is better.

Set your fuel pressure at 5.0-5.5 psi. That’s all the pressure you need.

If you are going to use your Holley pumps, I would take them apart, pull the spring out of the bypass and using small plastic tubing you can buy about anywhere, replace the spring with the tube.

You don’t want a bypass at the pump and at the regulator.

With the bypass in the pump blocked off and a -8 line going forward you’ll have about 24-26 psi going up. That’s all they’ll make. If you use a -10 line it will drop it to about 20 psi.

I never use bigger than -6 from the regulator to the carb(s). There is no need for a -8 line there, but it doesn’t hurt anything. It’s just not needed.

That’s about all I can think of for now.

There is no way I’d do a fuel system today without a bypass. And I started using a bypass in 1984.

I was ridiculed horribly for it. It works.
 
Newbomb Turk said:
Whatever you do, plumb the system for return line and use it.

Buy a QUALITY return style regulator. The big Mallory 4 port was the best but you can only find them used any more. I have one.

With the pumps you have you can probably use the smaller Mallory bypass regulator and be fine.

No smaller than -10 from the tank to the pump(s). These pumps are designed to push, not suck. So any restriction to the pump(s) is bad. -12 is better if you are nearing 800 hp or more.

No smaller than -8 from the pump to the carb(s). -10 is better.

Set your fuel pressure at 5.0-5.5 psi. That’s all the pressure you need.

If you are going to use your Holley pumps, I would take them apart, pull the spring out of the bypass and using small plastic tubing you can buy about anywhere, replace the spring with the tube.

You don’t want a bypass at the pump and at the regulator.

With the bypass in the pump blocked off and a -8 line going forward you’ll have about 24-26 psi going up. That’s all they’ll make. If you use a -10 line it will drop it to about 20 psi.

I never use bigger than -6 from the regulator to the carb(s). There is no need for a -8 line there, but it doesn’t hurt anything. It’s just not needed.

That’s about all I can think of for now.

There is no way I’d do a fuel system today without a bypass. And I started using a bypass in 1984.

I was ridiculed horribly for it. It works.
Click to expand...
Thank you!
 
There is a good diagram on the Pro Systems website. From tank to pump use a pre filter then run the lines from the pump to the carb or carbs and the final fuel filter. Then line from carb to regulator and then from the regulator back to the tank.
 
I am using the Mallory return reg, been on the car about 18 years. I run a 1/2" return line. Important that return line is not restrictive because it can cause pressure fluctuations.
 
I would look at some of the Summit ready made fuel systems. They are pretty nice. I've installed several.
 
I am totally confused here on the plumbing from the tank forward and back.
Tvt59 and Newbomb seem to contradict each other, or, is it bad wording. I did look at the Pro systems site, blurred pictures and printing. I have an old '69 Road Runner, was probably a race car at one time, it's street now. The old fuel cell in the trunk was way over the hill, as was the -8 fuel line up to the regulator and beyond. It has a Carter fuel pump (electric) with a canister filter that was before the pump. So I am replacing the whole fuel system up to the duel quads, it's a Gen ll Hemi at .070 over and stock stroke, so, 440 cu in. I do want to have a return fuel line. Was looking at a tanks stock fuel tank with in tank pump, but after borrowing a stock fuel tank, it's going to be in conflict with the coilover, ladder bar, Dana 60 suspension. So, going back into the trunk with a 15 or 16 gallon plastic fuel cell, probably an RCI. Had planned on 3/8" copper/nickle fuel line with -8 flared AN fittings. So, I am still confused about the plumbing order. We could do this through pm if necessary.
 
CRUZE 418 said:
I am totally confused here on the plumbing from the tank forward and back.
Tvt59 and Newbomb seem to contradict each other, or, is it bad wording. I did look at the Pro systems site, blurred pictures and printing. I have an old '69 Road Runner, was probably a race car at one time, it's street now. The old fuel cell in the trunk was way over the hill, as was the -8 fuel line up to the regulator and beyond. It has a Carter fuel pump (electric) with a canister filter that was before the pump. So I am replacing the whole fuel system up to the duel quads, it's a Gen ll Hemi at .070 over and stock stroke, so, 440 cu in. I do want to have a return fuel line. Was looking at a tanks stock fuel tank with in tank pump, but after borrowing a stock fuel tank, it's going to be in conflict with the coilover, ladder bar, Dana 60 suspension. So, going back into the trunk with a 15 or 16 gallon plastic fuel cell, probably an RCI. Had planned on 3/8" copper/nickle fuel line with -8 flared AN fittings. So, I am still confused about the plumbing order. We could do this through pm if necessary.
Click to expand...
I looked at the Pro Systems diagram as well. NB Turk is explaining that the bypass should come after the regulator is fed. Say at the end of the line, so to speak. There are diagrams that bypass before the regulator, yet that seems to defeat the objective.

Just "my" understanding of the system function.
 
If you go to Aeromotive’s website, and search around a bit you can find diagrams of how to plumb just about any fuel system for just about any HP level. Mild to wild. Click on the pump you’re interested in using and they’ll show you a diagram that is fairly detailed on how to piece together the system.

Example
9EF36E17-69D7-481F-9447-2C14714C6F79.png
 
The diagram you show makes sense to me now, sometimes wording gets turned around. They may say the same thing, but it doesn't read that way!
Thank you TT5.9mag
 
If you run a pre filter before the pump, it can't be the finer filtering level like 30 microns. It needs to be 100+ as to not restrict things.
 
I will have to see what kind of filter this is, it almost looks like the Carter electric pump. It has a replaceable filter element.
 
If it's the 1509 Summit filter, it's saying 10 micron. When I go out to the shop will see if I can nail this down.
 
another fun fact. If you use a cellulose filter, you have to be VERY careful with ethanol because it breaks down the glue holding the filter element together.

Took a couple of those chrome canister fram filter apart to service and the thing was gooey mess.
 
No alcohol here, knowingly! I am an alcoholic! But.... I used to haul gasoline and understand the term MISDROP.
 
I am using the Carter #4600 pump, 100 gph. It is also used on a drag car that runs 119 mph.

For a filter, I use a spin on filter from a small diesel truck, mounted under rear of the car.

Think of a return system like this: the engine takes the fuel it needs & the rest is returned[ bypassed ] to the tank.
 
For fuel line, I've used HotRodFuelHose.com, it's PTFE lined so you have no worries about rubber deteriorating over time. Cut the lengths you need, add your AN fittings, it looks great and I've never had a problem with it.
 
Not a race car, but PTFE braided line, Fragola fittings, "Corvette" filter/regulator mounted on the frame near the tank, in-tank pump, 1 line up to the tbs.

20190110_174628.jpg


20190109_204026.jpg
 
Illahe said:
I looked at the Pro Systems diagram as well. NB Turk is explaining that the bypass should come after the regulator is fed. Say at the end of the line, so to speak. There are diagrams that bypass before the regulator, yet that seems to defeat the objective.

Just "my" understanding of the system function.
Click to expand...
The regulator is after the carb and the by pass leaves the regulator and returns to the fuel tank
 
This is exactly what confused me, regulator after the carbs? To me that is like closing the gate after the horse has left. Not the way the diagrams I have looked at either. Am also talking with RCI for a custom tank and checking into possible PTFE lines.
 
CRUZE 418 said:
This is exactly what confused me, regulator after the carbs? To me that is like closing the gate after the horse has left. Not the way the diagrams I have looked at either. Am also talking with RCI for a custom tank and checking into possible PTFE lines.
Click to expand...


If it’s a bypass regulator it will go to the carbs and then return.

When guts where using non return style regulators as bypass regulators there was some odd stuff done.

BTW in 1984 a Holley engineer said there is never a reason to run a bypass.

Holley is wrong. A lot.
 
Newbomb Turk said:
Holley is wrong. A lot.
Click to expand...
Like having the welch plug thread in style on new carbs, press in style on older carbs, but more annoying press in style on new replacement bowls.
Also, my tbs have the return springs integrated into the tbs, there's an idea.
No external brackets hanging off everywhere or multiple springs getting in the way or finding decent springs the correct length/spring rate, times 2 for me when I had carbs.
 
matthon said:
Like having the welch plug thread in style on new carbs, press in style on older carbs, but more annoying press in style on new replacement bowls.
Also, my tbs have the return springs integrated into the tbs, there's an idea.
No external brackets hanging off everywhere or multiple springs getting in the way or finding decent springs the correct length/spring rate, times 2 for me when I had carbs.
Click to expand...


I was speaking of carbs. No clue on their EFI.
 
I'm surprised the PTFE police haven't shown up to profess you should only use 'conductive' pfte hose if you decide to go that route.
 
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