Fuel System Questions (efi Conversion)

Decurion

Member
Sep 28, 2006
353
0
16
Livonia, MI
So now that Im beginning to run the fuel system, Ive come to a point where Im in unfamiliar territory. The fuel system will, obviously, be a complete scratch build. I bought a new stock replacement wagon sending unit since the old one was trashed anyway, external high pressure pump, and a large filter. My plan was to use the large filter ahead of the pump as sort of a surge tank to help eliminate air bubbles, then aluminum hard line up to the engine compartment, and braided hose between the hard line and stock H.O. fuel rails. Now Im looking at the aluminum tubing and it says 25psi max. Ive also heard of aluminum tubing rubbing and work hardening against the clips that hold it in place and eventually cracking. That wouldnt be such an enormous deal on a carb'd application, but with perhaps as high as 50 pounds of fuel pressure on tap, that could get ugly quick. On the other hand I can run braided steel or push lock hose, but with fittings and everything thats around $300+. The other option is to run stainless tubing, but that'd be a little harder to work with and wouldnt offer any cost savings at $80 per 20' coil. Im thinking the push lock hose may get the nod for ease of installation, but what have you guys done that are running EFI?

My other question is what fitting(s) do I need to connect my fuel rail to an AN fitting? Are these right?
http://www.jegs.com/i/Aeromotive/027/15123/10002/-1?parentProductId=
http://www.jegs.com/i/Aeromotive/027/15124/10002/-1?parentProductId=
 
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rbohm

SN Certified Technician
Apr 12, 2002
6,538
513
204
60
tucson,az
you can use mild steel tubing for the fuel line runs. it is fairly easy to bend and wont work harden like aluminum will, and it will handle the higher EFI fuel pressures. remember that is what they factory uses. another options would be to use a low pressure electric fuel pump near the tank,as you would in a carbed system, and run your aluminum fuel line up to a real surge tank, one that holds about a qt of fuel will do nicely by the way. use a holley float bowl along with its attendant needle valve to control the fuel level in the surge tank, and then run steel line to the high pressure pump and to the injectors, and as a return line. now the beauty of running a surge tank is that you dont have to run the return line all the way back to the main gas tank, but rather to the surge tank under the hood. just set the return line to run return fuel to the bottom of the surge tank to prevent issues with static electricity.
 

65ShelbyClone

Founding Member
Sep 9, 2000
4,597
21
109
Antelope Valley, SoCal
How about using the factory steel hardline as the high pressure feed for EFI? It seems fairly trivial to trim and flare the ends for -AN fittings. It would simplify the plumbing somewhat and ~45psi wouldn't be that structurally taxing...I hope. My hardline is practically new, so it would be nice not having to replace it.

I'm gathering parts to inject my '68 and figured this thread was relevant enough to dig up again. ;)