dual feed returnless rails.

[Mars]

This question pertains to the 3500 LX9 or the 3900LZ9 or any other returnless fuel rail setup.

Would it be beneficial at all to feed the rail from both ends ?

I was thinking that maybe when I install my Earomotive FPR that I would run a -4AN hose to the test port (removing the shrader valve of course) then another line to the normal -6 feed port, this way the rail will have another source of fuel to help avoid getting sucked dry...

My FPR has like 3 ports on it, so I can run a gauge, one port to the -6 and one to the -4 test port.

I have 60# injectors and they will likely be about maxed out at times. IE : I will be using ALOT of gas.

Comments ?

[caffeine]

I've decided to run my return line from the schrader valve, as I've read of people doing this on LS1s.

[Mars]

Umm, so then did you just cap off the return on the FPR ? or leave it open ?

[caffeine]

My FPR just has one feed port and one return port. I could also connect it by teeing off the feed line.

[caffeine]

[Mars]

You went with Option #1 then ? Just so I'm clear, looks that way in the pic, I may do the same.

You should give me the part numbers for the fittings that you used in the top right of your pic there, looks like a 90* and some kind of swivel 90* ??

I'm pretty sure I'll do mine the same way.

[caffeine]

Ya option #1. Ill gather the part numbers for you. The test port is -4AN so since my regulator uses a -6 return line I have a -6 to -4 fitting right on the rail.

I ran the nitrous fuel feed for my Fiero from the test port and it worked well. Hoping it works well for a FPR as well.

[Mars]

If you're getting the part numbers, can you also tell me how you are adapting the braided hose to your stock hard steel lines ? I think you need to flare and use an -AN nut on the hard lines right ? or is there an easier way to do that nowadays ? (compression fittings ??)

Yeah by the pic it sure looked like -6 line from the test port. (which is cool cause I just bought some.)

My fuel lines are a mess of rubber to steel with shitty clamps and it will prolly fail tech if they got picky. need to fix this ASAP.

[caffeine]

The fittings to bolt to the stock hard lines are M16x1.5 and M14x1.5 IIRC. Russell makes fittings that bolt right on and seal with the stock o-rings. To my fuel lines at least. I would think if your car is an 88 it should have the same fuel lines.

Ya technically you're not supposed to have more than 1 ft of rubber line in the fuel system I think, and the gas tank-hard lines are probably around 6" as is.

[caffeine]

Part #s I used in my setup

Test port - FPR:
659950 -4 Female to -6 Male (test port adapter)
614806 -6 Female to -6 Male 90*
610160 -6 90* Hose end
Hose to FPR wherever you mount it
Hose to another -6 90* hose end (45* would probably be just as good but cost more )
640820 -6 Male to M14x1.5 (Stock return hard line)

Feed line:
644120 3/8 "Screw-on" quick disconnect fitting to -6 Male (You can get fittings that push onto the fuel rail like stock as well but some seem to have had problems with them popping off. These ones just have a piece that slips over the fuel rail below the flare and the upper portion of the fitting threads onto them for a more permanent seal)
I used another 90* hose end to come off the fuel rail adapter then run a hose to the stock hard line adapter
640830 -6 Male to M16x1.5 (Stock feed hard line)

[Mars]

thanks man.