[ZeGermanHam]

Originally Posted by Formulajones

What I have had issues with are running systems with the return line very short at the back of the tank. Especially when regulated down to carb fuel pressures. The feed line fuel tends to sit more stagnant and absorb more heat and with low 6-7 lbs. of fuel pressure I've had some issues with heat soak.

When I move the regulators close to the carb and run a full length return line, most of that fuel is heading back to the tank, where it mixes with the cooler fuel in the tank. That seems to have solved any heat soak issues I've seen with carbs.

Thanks all, and thanks Formulajones for this helpful information. It has been an informative read. I ran a 3/8" full-length return line when I plumbed the chassis, so it should be very easy for me to place the regulator close to the carb and send fuel back to the tank. The regulator probably does a better job of regulating the pressure when it's near the carb, anyway.

And it seems there is total consensus that using a high-pressure pump and regulating it down to carb pressure is not an issue. I even reached out to Tanks Inc. for input, and they said they don't carry low-pressure pumps for carbs anymore because they had such a high failure rate (for whatever reason), and they now recommend using a high pressure pump as you and others here recommend. That will make life much easier for me!

[neill]

I am installing an aeromotive 340lph tank and universal bypass regulator. They want a 1/2" return line. Just wondering what people here would suggest for this. I have a long enough piece of 1/2" aluminum russel line but I'm just not that comfortable with this on a street car. Thanks for any suggestions.

[chuckies76ta]

Originally Posted by neill

I am installing an aeromotive 340lph tank and universal bypass regulator. They want a 1/2" return line. Just wondering what people here would suggest for this. I have a long enough piece of 1/2" aluminum russel line but I'm just not that comfortable with this on a street car. Thanks for any suggestions.

A read about Aeromotive 340 pump.
https://aeromotiveinc.com/wp-content...6902-0revA.pdf

"This pump is ideal for applications requiring more flow while retaining the factory lines and mounting provisions available in the Original Equipment (O.E.) configuration."


FAQ: https://aeromotiveinc.com/tech-help/...th-fuel-pumps/ They are talking 1/2" Return..

14.) Q: I know the 340 Stealth Pump is used for high-pressure EFI engines but my engine is carbureted, is there any way I can use one too? If so, what regulator would I need and how should I plumb the fuel system?

A: Contrary to what most people think, pumps don’t necessarily pump pressure, what they do pump is flow. Now, some pumps flow more at higher pressures than do others, which is what separates a high pressure EFI pump from a low pressure carbureted pump. That said, there’s nothing to say you can’t run a pump capable of EFI pressure at carbureted pressure levels.

What is required for all pumps capable of high pressure is the use of some form of external, bypass regulator (high pressure pumps have no internal bypass and cannot be run with dead-head or blocking style regulators). To use the 340 Stealth pump for a carbureted engine is not only possible, these little in-tank pumps can be part of a very effective carbureted fuel system, capable of both high horsepower and quiet, continuous duty street operation.

The secret to success with the 340 Stealth Pump and carbureted engines is to select the proper carbureted bypass regulator, Aeromotive recommends P/N 13204, and to install a large enough return line, ½” or AN-08 from the regulator back into the top of the fuel tank, in order for the regulator to work properly. Note: the OEM EFI top hat and return connection are too small for carbureted applications regardless of the return line size used. You must increase the connection for the return line in the top of the tank to ½” or AN-08 as well.

[Torquewar]

Chuck 76 ta your post describes exactly the system I run. It’s been flawless for yrs now and honestly one of the best purchases I’ve made. Always liked Aeromotive products and their tech dept has been spot on with advice.

[chuckies76ta]

Ya, I run 2 cars with Aeromotive A750 pumps and AN-06 lines return and supply and never had any issues. I'm like you, I really like there products. Expensive but good.

[Formulajones]

The key to running a big pump at really low pressures is having a return line big enough to return all the fuel.

If you have a pretty big pump and you're turning it down to 6-7 psi for a carb you'll know immediately if your return line isn't up to the task, because it creates a fountain out the vent tube of the carb that'll shoot 2 feet up in the air

Been there.

Neill, Some things to think about with aluminum line. With ethanol fuels it's susceptible to corrosion. But the one thing I don't really like about them back when I was playing with them using external pumps is the aluminum line transmits a lot of noise through the car. Was noticeable on the little Vegas and Monzas I was doing this on back in the day. Maybe a big car with a lot of sound deadener, not so much. But just a little pet peeve I had with it.
I know the aluminum is easier to work with and cheaper to buy, but I much rather prefer either steel line I make myself, pre bent stainless lines from Inline-Tube, or some form of AN line, usually PTFE that is safe for all fuels.

[grivera]

Originally Posted by neill

I am installing an aeromotive 340lph tank and universal bypass regulator. They want a 1/2" return line. Just wondering what people here would suggest for this. I have a long enough piece of 1/2" aluminum russel line but I'm just not that comfortable with this on a street car. Thanks for any suggestions.

I have aluminum 1/2" supply/return from tank to engine compartment without issue. I believe HWYSTR455 has done the same.

[leeklm]

"I know the aluminum is easier to work with and cheaper to buy, but I much rather prefer either steel line I make myself, pre bent stainless lines from Inline-Tube, or some form of AN line, usually PTFE that is safe for all fuels."

I have been using the nickel copper line for a couple years now on the 68 , but only run 10% ethanol pump gas. The stuff is easy to work with, and not as flimsy as aluminum. Not sure about longevity?

Fwiw, a 3/8 return line seems to work well with the 240lph pump, but of course bigger is better if going to a larger pump.

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[ZeGermanHam]

Originally Posted by leeklm

Fwiw, a 3/8 return line seems to work well with the 240lph pump, but of course bigger is better if going to a larger pump.

On that note, I ordered the Holley Sniper EFI tank & pump setup. I believe the pump supplied in the kit is a 255lph Walbro unit. Do you think my 3/8" return line will be sufficient?

[leeklm]

Typo on my part... I also have the 255 walboro pump, 3/8 feed and return, and RobMC regulator. This is my second car with this setup and no issues.

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[ZeGermanHam]

Great, thanks.

[neill]

Appreciate all the input guys thanks

[78w72]

good info in this thread. related to aeromotive & return lines, they make a kit you can install into an existing or new tank that regulates the fuel internally in the tank as part of the pump... no need for return lines & they say it work just as well as a full return system. pretty sure its for carb'd set ups as well as EFI. i was considering one early on but dont like the idea of cutting a hole in an existing tank & will go with tanks inc if/when i get away from the robbmc mech set up i have now.

[Formulajones]

Originally Posted by 78w72

good info in this thread. related to aeromotive & return lines, they make a kit you can install into an existing or new tank that regulates the fuel internally in the tank as part of the pump... no need for return lines & they say it work just as well as a full return system. pretty sure its for carb'd set ups as well as EFI. i was considering one early on but dont like the idea of cutting a hole in an existing tank & will go with tanks inc if/when i get away from the robbmc mech set up i have now.

. They've had a stealth kit on the market for several years. Is that the one you are referring to??

I guess cutting a hole in the existing tank is the sketchy part, and no baffling might be an issue. I think one of their solutions to that early on was laying down that absorbent mat in the floor of the tank but I'm not totally keen on that idea.

[78w72]

Originally Posted by Formulajones

. They've had a stealth kit on the market for several years. Is that the one you are referring to??

I guess cutting a hole in the existing tank is the sketchy part, and no baffling might be an issue. I think one of their solutions to that early on was laying down that absorbent mat in the floor of the tank but I'm not totally keen on that idea.

yes been out for ~5 years or so, its the "phantom" returnless version & they make return style too... but they dont get mentioned much on these intank elect pump threads, looks like a nice set up & aside from cutting a hole in the tank (not a big deal on a new tank) they are an easy way to go elect without a need for a return line.

the baffle they use is a big foam "cup" the pump module sits in, not as good as a real baffle like tanks inc but they say it does its job very well. & another new thing they've added is an extension tube that you can direct to any area of the tank, it works in conjunction with the foam baffle so both parts pick up fuel at the same time to prevent any starvation for drag or auto-x use. the video they have shows it working very well. pretty slick set up & not very expensive.

https://aeromotiveinc.com/product/carbureted-phantom/

the absorbent mat is holleys hydra-may, very expensive & im not sure how well that works when uncovered for any period of time but im sure its better than nothing at all.

[Formulajones]

Originally Posted by 78w72

yes been out for ~5 years or so, its the "phantom" returnless version & they make return style too... but they dont get mentioned much on these intank elect pump threads, looks like a nice set up & aside from cutting a hole in the tank (not a big deal on a new tank) they are an easy way to go elect without a need for a return line.

the baffle they use is a big foam "cup" the pump module sits in, not as good as a real baffle like tanks inc but they say it does its job very well. & another new thing they've added is an extension tube that you can direct to any area of the tank, it works in conjunction with the foam baffle so both parts pick up fuel at the same time to prevent any starvation for drag or auto-x use. the video they have shows it working very well. pretty slick set up & not very expensive.

https://aeromotiveinc.com/product/carbureted-phantom/

the absorbent mat is holleys hydra-may, very expensive & im not sure how well that works when uncovered for any period of time but im sure its better than nothing at all.

Yeah I installed one years ago in a 57 T-bird I restored. He went FAST EFI on the original Y-block and initially started with an inline pump. That didn't last long and I told him it wouldn't, lol. They don't make a baffled EFI tank for these cars, least not at that time and probably still don't, so I did the Stealth setup. Works fine for what he's doing, it's just a cruiser.

I see they call them Phantom's now. They were referred to as Stealths back when I did that.