Well, I found out my return line back to my tank is well too restrictive for the fuel pump I am running. (Walbro 255lph) I have the Mallory 4309 regulator and a holley DP carb. The pressure would not drop below 10-11 psi so I am going to route a larger return line. What is the easiest, or the best solution in doing this? I'm more or less confused on what i have to do once I get the new line back to the tank???

Thanks for the input.

 

Dumb question why are you running a tpi high pressure fuel pump?

 

"TPI" and "high pressure" become "carb" and "high volume" when the pressure is dropped to carb levels with a return-style reg.

 

That's why. I'm just trying to figure out how to run 1/2" steel lines. I'm sure I'll be able to run everything back to the tank, it's when I get to the top of the tank that I'm worried about. Does anyone know if there's a company that makes aftermarket pick-ups?

 

Haven't heard of any. You're probably going to have to modify it yourself.

Most people using that size of line go to a cell.

 

That's out of the question. This is mostly a street car. I've got a pretty good idea on what i want to do. I'm just hoping there is enough room from the top of the tank to the bottom of the trunk floor to run two 1/2" lines. I would run the two lines from the engine bay to the tank in stock formation using a compression fitting where the two lines would connect towards the bottom of the tank (stock location). Towards the top of the tank at the pick-up I will cut out the stock return and supply line and drill out the holes larger to accomodate the new lines. Maybe use jb weld at the top of the pick up? Not sure how to adapt the stock 3/8" line from the pump to my new line though...

 

Ok, so i have a pretty good idea of what I'm going to do. What's your guys' opinions on this? Can I run all 1/2" steel line w/ compression fittings? Will they leak? I'm going to have my dad's buddy make two 90's to go to the top of the pick-up. from there I'm just going to mock the stock line routing up to the engine bay. Can I just pick up thin wall 1/2" tube steel? What psi is the steel line good to? And I want to make sure the compression fittings don't leak.

Thanks for the input.

 

I ran new 3/8" steel supply/return lines on my car. Not 1/2", but still the same idea. I wouldn't use compression fittings, but others do. Wherever I needed to make a connection, I used fuel injection rubber hose and clamps. It allows for flexibility and less chance for leaks. You have the right idea using steel line over aluminum.

 

Thanks for the reply. I wanted to run steel line due to durability and all. I hope if I take my time and do it right it won't leak w/ compression fittings. How much pressure can thin wall steel tube hold? (1/2")

 

1/2" diameter, 24ga (.024") thick steel tubing has a burst pressure over 1,000psi (safety factor of 3). I wouldn't want to go too thin and that has nothing to do with pressure and all to do with durability.

 

I've been running 3/8" aluminum with compression fittings on the '57 since 1998. Been running it with an electric pump back by the tank since '08. No problems whatsoever. Aluminum can handle plenty of pressure, as can flared and compression fittings. No flow problems to an approximate 500 HP (including a 100 shot) with E85 (requires more volume than gasoline).

I've got aluminum line on Berlinetta #2 with the LS1 pump. Haven't run it a lot yet, but the run time I do have on it, including a lot more pump-on time than engine-run time, hasn't shown any leakage problem anywhere.

There's nothing wrong with using aluminum tubing for fuel line. It's a lot easier to work than steel.

 

Thanks for the reply. I'm still debating between aluminum and stainless steel but leaning towards the steel. I can get the stainless for about a buck a foot at my buddies shop. I just need access to a tubing bender and a tubing flare tool.

 

Is the 24 ga. doable to bend with a tubing bender?

 

I'd think so. The 3/8" I used had a .028" wall thickness and I hand bent it.

 

Get the stainless and use double flare fittings. I worked at a fuel line OEM manufacturer and had access to pretty much all types of tubing that was currently out there. Double flare is a lot better than using compression fittings. Plus if you take it apart, your chances of being able to get it to seal again are waaayyy better with a flare fitting.
On mild steel a double flare is the way to go, for stainless you will only be able to put a single flare on it, because the stainless work hardens when you bend it more than about 30 degrees.
The single flare will work fine and be very reliable, but yoou might need to modify the inv. flare nuts by grinding down the lead in threads. this will prevent it from bottoming out on the mating part, since the single flare tubing is only single thickness.

 

Would you like to go into more detail on double vs single flare? I'm not sure what the difference is? Wouldn't the fittings be the same?

 

i am going to run a holley proform 750 backed by an inline areomotive ss fuel pump

http://aeromotiveinc.com/products-pa...l-pump-orb-08/
its all going on a 383 small block chevy.

with that setup i'll need to convert my return line to a 3/8 or 1/2?

 

i would say 1/2" or 8 an fittings = more flow the better, im running 1/2" on my holley black setup