[Squidward]

Hi. General fuel system and automotive inquiry here.

I enjoyed EFI so much on my Lemans, I decided to put it on my 67 Firebird. I am going with a 600 hp Easy Street FiTech system. It is the same system that my Lemans uses with the exception of no timing control.

I want to do an in-tank electric pump on my existing tank. I want to run an-6 soft lines out of the pump, and go immediately to an efi return style regulator right outside the gas tank. The regulator would then send a 58 psi single supply line forward to the efi, and send a return output back to the tank.

I want to use the existing 3/8 mild steel fuel line to run fuel forward, and adapt both ends (aft at the tank/regulator, forward to the mech pump end of the hard line) to an-6 fittings and efi rated hose. I don't want to run soft hose the whole length of the car. I also don't want to run a big return line from front to back, either. This is why I want to keep the regulator in back.

What are successful options for putting an fittings on the end of a mild steel 3/8 tube? If I am understanding it correctly, I could cleanly cut the end of the tube, slide on female nut and sleeve, then do a 37 degree single flare on the tube. Alternately, my local hose/fitting supply store suggested something like this:
https://www.redhorseperformance.com/...s/3100-06-06-2

Any experience with either option?

Thanks!

[Marv]

Have you considered using a full pump & cradle from a Pontiac G8? It keeps the reg and return in an adjustable cradle that sits in the tank, so you have to wire the pump and fit a hose to the single 3/8 outlet. 5th Gen Camaros also used this set-up as they're based off our VE Commodores down here

I am doing this on my car and will be running a rubber line from the top of the pump cradle to the stock metal line.

[Squidward]

That's an interesting solution. Not in my plans, tho. I considered using the Corvette LS pressure regulator/filter, but would have to incorporate the quick connect fittings/adapters instead of just sticking with AN fittings and push-lok hose. It would put me in the same situation with the quick connect fittings. But what you suggested is a more modular solution to what I am trying to achieve. Thank you!

[Cliff R]

If you are working with steel fuel lines and inverted flare fittings ALWAYS double flare them, as single flare is weak and dangerous, especially on the pressure side of a fuel system.......Cliff

[Marv]

Originally Posted by Squidward

That's an interesting solution. Not in my plans, tho. I considered using the Corvette LS pressure regulator/filter, but would have to incorporate the quick connect fittings/adapters instead of just sticking with AN fittings and push-lok hose. It would put me in the same situation with the quick connect fittings. But what you suggested is a more modular solution to what I am trying to achieve. Thank you!

There are adapters available that allow you to fit AN fittings to the quick-disconnect OEM GM style connectors

[Squidward]

Originally Posted by Cliff R

If you are working with steel fuel lines and inverted flare fittings ALWAYS double flare them, as single flare is weak and dangerous, especially on the pressure side of a fuel system.......Cliff

I want to do 37 degree AN fittings on the ends of the 3/8 tube. Everything I was seeing was 45 degree gets the inverted double flare, and the 37 degree gets a single. I've done many 45 degree inverted double flares, but all my AN experience has been just "plug and play" with push lok hose, or pre-fabbed assemblies.

I am really only seeing a couple of options, which is nut/sleeve/flared tube, or one of these slip-on fittings with a ferrule on the outside of the tube that apparently does the flaring when you tighten it down. Am I understanding the AN standard correctly? Thanks!

[Squidward]

Originally Posted by Marv

There are adapters available that allow you to fit AN fittings to the quick-disconnect OEM GM style connectors

I did explore that, and it was compelling. But as I started thinking out the project, I decided I wanted to minimize the use of adapters. The pump I am looking at has AN outlet and return fittings, and it will also allow pulse width modulation of the pump to control pump speed. I am also looking at a regulator that also uses AN ins/outs. Thanks!

[vidguy]

https://www.swagelok.com/en/catalog/...=SS-600-6-6AN#


I used this type of fitting on my 1/2" hard lines in my GTO and my Formula. Connected the 1/2" lines to -8 PTFE Braided lines I made.
They work REAL well.
I think this would work for you. Available in all sizes, combos and configurations.

[Squidward]

Originally Posted by vidguy

https://www.swagelok.com/en/catalog/...=SS-600-6-6AN#


I used this type of fitting on my 1/2" hard lines in my GTO and my Formula. Connected the 1/2" lines to -8 PTFE Braided lines I made.
They work REAL well.
I think this would work for you. Available in all sizes, combos and configurations.

Does that require a flare, or is it just a slip-on-and-torque fitting?

[64speed]

This whole an fitting thing was the main part about the holley sniper that I dreaded. I finally called holley tech and Summit tech, got them on a three way call and let them figure out my fuel system. I am running the sniper fuel tank so I have a barb fitting coming off the outlet of the tank into earls vapor guard rubber hose. Connects to my factory 3/8s fuel line. Then at the engine end I have as an to 3/8 barb adapter to fuel line hose clamp the line on. Return line is the same thing in reverse.

[Fishin2Deep4U]

I am running a 4 bar system in my Bird.

5th gen camaro fuel pump in a modified tank. -6 Teflon lined from tank to 3/8" hard line to the front of the cowl. -6 Teflon lined to the rear of the rail. I may change that at a later date. I think the push should go to the front. I am concerned about heat front the exhaust.

I used flare nuts on the stainless hard line. I know many have used Swagelocks with success. I simply did not trust them. That in no way means it is not a good solution. Just wasn't for me.

I am glad I went with the internal regulator. Simple and clean.

Now I just have to put it all back together. Blown apart for paint.

Dave

[flat-bill]

Will it be a problem having he regulator at the back? I would think that it would be better to have the regulator near the injectors so there would not be a non compensated fuel pressure drop in the line running forward. Billk

[Fishin2Deep4U]

It's not an issue having the regulator out back. The ECU will compensate for the pressure loss at the rail.

The ideal solution is to run a PMW controller that references rail pressure and an 80 psi bypass regulator. That way you have constant pressure at the rail. The regulator out back will obviously reference pressure where's it's mounted. The typical setup has the regulator on the return side of the rail and uses a vacuum reference.

In the 4 bar system, this all seems to be less of an issue. Unless you are running boost. Then I would rethink the entire setup.

Dave

[Squidward]

Well, I have the system planned and in progress. I installed the pump into the FB tank. It is a very low profile pump with vent, pressure, and return 6 an fittings, and runs a 255 lph electric in tank pump.

A first gen fuel tank has the deepest portion of the tank in the forward end, and it retains the factory gauge sender for this pump setup. I had to work around some tank baffle issues on the top to get things flattish. It is not the prettiest, but I think it will work.

I will be running hard lines out of the pressure and return ports to just in front of the tank. I will then run a combo of push lock style fuel hoses and AN fittings to the Tanks, Inc. return style regulator, which will also be mounted directly in front of the tank. Outlet from the regulator will go to the passenger side of the car to join up with the 3/8 hard tube. I did AN6 tube nut and sleeve, and the flare seemed to go well. I also did AN6 nut/sleeve/flare on the hard line up by #6 cylinder, where it will join another push lock hose that will go to the throttle body. Keep you fingers crossed that these 2 flares don't leak, or I will be doing some custom fuel line front to back.

Question: The FiTech has a 58 psi regulator built onto the throttle body. The ecu controls pwm of the pump via rpm/throttle position so that it doesn't run full speed at low demand. Should I set my rear regulator to supply at 58 psi, or go a little higher than that (60 something), or go lower (52-55)?

[Bandit400]

My Holley Sniper has an internal regulator, and my rear regulator is set for 58.5 (same as the one in the Sniper throttle body). Mine runs great. Id just set it for what presaure the system requires, and leave it at that.

[Fishin2Deep4U]

You really only need the rear regulator as a safety valve when you have a forward mounted regulator. If both are set at the same pressure the rear one will open first, all thing s equal.

I would go to 80 psi in the rear and let the regulator in the fuel injection unit make the changes at the rail.

Dave

[Bandit400]

Just something to be aware of. It sounds like he is running a feed line up to the TB, with no return line coming from the throttle body. His return line comes from the regulator in the rear.

If he sets his pressure higher than the TB requires at the rear regulator, the TB regulator in the front will not have a return line to dump the excess pressure into.

[Fishin2Deep4U]

I missed that. If he's deadheaded, that may complicate matters.

Dave

[Squidward]

Yes, it will have only a single supply forward to the tb.

I will probably either set it at 58 psi, or slightly higher, and see what works.

One thing of interest is that the Fitech's on board regulator is connected to the only small manifold vacuum nipple. This references fuel pressure to the manifold. My first FiTech didn't do that.

Bandit, does your Sniper use reference pressure on the regulator?

[Bandit400]

My Sniper onboard regulator is preset at 58.5. I am not aware of a hookup from the MAP reference. I do know that it reads fuel pressure on the handheld display.

In regards to your setup, I would set your rear regulator to 58.5 PSI and forget about it. I have mine plumbed the exact same way, and it works beautifully. I have no fuel starvation or pressure issues.