fuel injection supply and return

Moderator: Tom Notch

Post Reply
shepherd
Posts: 101
Joined: Wed Nov 28, 2012 7:30 am

fuel injection supply and return

Post by shepherd » Fri Aug 07, 2015 9:41 pm

I'm setting up my car for megasquirt injection, and have gotten to the fuel supply and return. I've previously run a 3/8" stainless line through the tunnel, with an-6 ends. Looking at the available hoses, it seems that the PTFE lined, stainless braided hoses like this one from Summit would be a good choice.
400º max and 2500psi, http://www.summitracing.com/parts/sum-220985
Using this to the rails, from the rails to the regulator, and then to the stock line back to the tank. Not sure how I'll connect to the stock line, may not do that. Is this line overkill, or is there a better choice? It will be supporting 2.1 liters now, and a 2.2 turbo later.
Is it ok to run the pump to one rail, then rail to rail, and finally to the regulator? Or should I split the supply and go to each rail separately?
The pump is a Walbro gsl392, and the regulator is CB's billet efi adjustable piece. Any advice is appreciated, I only want to do this once.
SD

User avatar
vwjim
Posts: 357
Joined: Thu Jul 04, 2002 2:01 am
Location: Under a bus in sunny Hampshire, the old one.
Contact:

Re: fuel injection supply and return

Post by vwjim » Tue Aug 11, 2015 2:47 am

I generally run -8 from the tank to the pump, then -6 after the pump.

And fine pump to rail to rail to reg' to tank.

User avatar
Chip Birks
Posts: 2477
Joined: Wed Mar 12, 2008 7:59 pm
Location: Pleasant Grove, Utah

Re: fuel injection supply and return

Post by Chip Birks » Tue Aug 11, 2015 3:12 am

It would be worth looking at anfittingsdirect.com, their stuff is all ptfe lined steel braid hose as well. Best price I've seen for the stuff. I just redid every inch of my system and used that for all of it. It takes some figuring out as far as hose assembly goes, but once you figure it out, the work goes pretty quickly. I went with 3/8 for everything, the plan is to support a 400ish whp turbo motor. Mine is setup similar to VWJim's layout. Only difference is that my pump is actually in my tank, so no gravity feed.

shepherd
Posts: 101
Joined: Wed Nov 28, 2012 7:30 am

Re: fuel injection supply and return

Post by shepherd » Sat Aug 22, 2015 9:13 pm

Chip, thanks for the heads up on anfittingsdirect, good place and I got nice stuff. Still cost me about $280 for all of the fittings, hose, and hard line. I have AN8 from the tank to pump, and then AN6 pump to filter, to 3/8" stainless hard line to the rear. I ended up with enough 3/8" hard line to run a return, so I did that also, and will plumb a AN6 bulkhead fitting into the tank for the return. All AN6 stainless braided PTFE between the rails and to the regulator. Question, as I'm only using one of the two pressure ports on the regulator, I'm going to add a liquid filled gauge to the other port. Any bad experience doing this? I've run my carbs this way, but the regulator is at 3psi not 45..
SD

User avatar
andy198712
Posts: 1601
Joined: Wed Apr 13, 2011 3:01 pm

Re: fuel injection supply and return

Post by andy198712 » Sun Aug 23, 2015 4:28 am

how much hardline did it take to run front to back? i'm thinking the same :)

shepherd
Posts: 101
Joined: Wed Nov 28, 2012 7:30 am

Re: fuel injection supply and return

Post by shepherd » Sun Aug 23, 2015 8:40 am

I bought a 25' roll on Amazon for cheaper than anyone else had advertised. It gave me enough to do both with a few feet left over. The 4 swagelock fittings for 3/8 tube x AN-6 were more money than the tube itself.

User avatar
andy198712
Posts: 1601
Joined: Wed Apr 13, 2011 3:01 pm

Re: fuel injection supply and return

Post by andy198712 » Sun Aug 23, 2015 10:46 am

cheers buddy! did you go right to the tank and into the engine bay?

shepherd
Posts: 101
Joined: Wed Nov 28, 2012 7:30 am

Re: fuel injection supply and return

Post by shepherd » Sun Aug 23, 2015 11:26 am

I ran them from just in front of the front bulkhead to under the parcel tray, all on the passenger side. So that either the front or rear flex to hard line connections can be serviced by removing the wheel. I have yet to mount the pump, regulator and everything else, to map out the exact routing. Positioning everything so that the hoses are short as possible, not kinked, and that every fitting can be turned with a wrench is always more of a puzzle than you would assume. I imagine I will add the return fitting next to the fuel sender, so that I can reach in to tighten the fitting. Being on the top of the tank it won't be subject to leak, though I'll have to add a tube from it to the tank bottom or else you hear the fuel splashing all of the time. For the tank pickup, I have the stock tank thread to AN-8 adapter fitting from CB performance. I'm about halfway through building the wiring harness, soon as I can clear the bench of crimpers and shrink tube I'll set up to start making lines. The hose ends that mate to the braided PTFE hose aren't as idiot proof and run of the mill AN fittings. You have to get the lengths just right, and install the brass crush bushing just right. As long as you do, the fittings are near bombproof.

Bruce.m
Posts: 152
Joined: Sun Aug 11, 2013 3:44 pm

Re: fuel injection supply and return

Post by Bruce.m » Wed Aug 26, 2015 6:15 am

I'm considering using a t-fitting under the tank for the return line but also having an extra pipe run to the tank top as a breather. That way you shouldn't get fuel pouring into the top of the tank as the fuel should settle in the breather at the same level as inside the tank. Any air in the lines should exit to the tank top.

?

Post Reply