Need input on fuel tank fittings

[Lo Cash John]

Hello all. I'm working on prepping my son's Ghia for EFI and wanted some input on the plumbing of the system.

The pump has a round nipple inlet that a -10 steel braided hose just fits over. With that in mind I welded a -10AN fitting to the bottom of the tank while doing some rust repair. I also added a little baffling to the tank floor to help keep fuel available to the outlet, even under extreme lateral loads.

My first thought was a -10 hose from the tank and straight into the pump. From there, use -6 (3/8) aluminum tubing and let the fuel do it's normal route through a filter, injectors rails, reg and back to tank. Thinking about it more, I decided I'd like to place a pre-filter BEFORE the pump so I was considering mounting one of these http://www.summitracing.com/parts/sum-g1507/overview/ under the tank, on the passenger side of the frame head. I'll use -10 hose from the tank and into the filter and then more -10 from the filter to the pump.

My first specific question: Does anyone think the fuel will not flow freely enough to the filter and pump? I mean we're talking -10 here.

My next question: While I'm still building, is there any reason to NOT return the fuel to the tank and instead, tie back into the pre-filter? At this point I have a -6 fitting ready to weld to the tank, but wanted some input first. I know lots of folks do the "swirl pot" setup to avoid welding on a gas tank or reduce fabrication time. In my case welding on the tank is no biggie.

Thanks!!

[Clonebug]

By the time I had my Pump and pressure filter mounted under the tank I was pretty well out of room.

I stacked my pump and a Golf filter on top of each other with 1/2 in feed lines since that was the pump inlet size.



Are you putting some of the stuff under the hood?




I just used a small metal pre-filter in the tank to pump line.

I have changed the feed line due to the hose wanting to kink when doing the 180 by using some brass fittings but it is basically the same otherwise.
No fuel flow issues to 17 lbs. boost.

[volksbugly]

Run a T off the an-10 fitting from the tank, then return your fuel line directly to the T at prefilter.

[Lo Cash John]

I think I'm going to stick with the fuel returning with a -6AN fitting on the tank. Before welding on the fitting I think I'll fab a small diffuser to weld onto it. This way if my son is ever low on gas (what kid doesn't pull this one) the fuel return stream won't spray all over the fuel sender float and make it act all wacky.

I think I'll be fine with mounting that spin-on filter under the tank and plumbing it in before the pump. The pump is being mounted out of the way so I'm not real concerned about room.

As for the rest of the plumbing, the pump will push through a -6 aluminum line running under the passenger side heater channel. I will place the fuel pressure regulator in the engine compartment behind the fender well. This will be concealed by aluminum panels we are fabbing for the engine compartment. I'm doing my best to keep the motor very minimalist and the engine compartment clean looking. I'm trying NOT to have hoses and wires all hap-hazard everywhere but make it look more thought out. We'll see how successful I am...

[jhoefer]

That filter is 3/8" NPT inlet/outlet which is reasonably close to what you'd get with a -8 fitting. The -10 lines can't gain you anything above that other than being able to easily attach to your pump.

That filter is also 10 micron which would be good for post-pump use to protect the injectors, but it won't work with the higher EFI fuel pressures so you can't use it post-pump. Using a 10 micron pre-pump filter can be too restrictive and starve the pump. And the suction might collapse a paper filter element like that. I would recommend a 100 micron filter (I like ones with a cleanable stainless steel element) pre-pump to catch the bigger stuff and a 10 micron high-pressure filter post-pump to protect the injectors.

[Lo Cash John]

Good call on the restrictiveness of the 5 micron filter. I just ordered a 100 micron inline filter with -10 fittings from Summit. I'll plumb than in between the tank and pump.

Not that I'm thinking about it, I'm having second thoughts on my pump location. I'm thinking about moving the pump to the rear of the car and have the pre-filter stay up front, under the tank. This will make for a more compact wiring harness and less chance of noise in the interior. The ECU and relay board are all mounting under the driver side back seat area. I'm setting up the EFI harness to be completely stand-alone from the "chassis" harness that's going in the car. This will make modifications and upgrades in the future much easier.

[Dale M.]

John.... I thought you new better.... Electric pumps push better then pull.... Pump needs to be directly under tank...

And it only takes one single wire from relay to pump....Hardly a BIG problem...

Dale

[risk]

I have a similar pre filter, 8AN, with 100 micron stainless mesh inside on the inlet side of my pump.

Welded 1/2" steel coupling to tank, threaded in an 8AN fitting that feeds the pre filter, then 8AN to pump.

The pump outlet is 6AN, and I used 6AN to GM fuel fitting adapter, GM style canister filter, then to 3/8" stainless through the tunnel.

Then 6AN feeds the fuel rails then hits the regulator mounted on the firewall, then goes back up front into the stock tank outlet via an adapter fitting.

Lots of fittings but gets the job done. Plus I can use the GM style fuel filter that is commonly available at parts stores.

[Lo Cash John]

Dale, I'm thinking it should be okay. If I put the pump in the back it'll be mounted low, like near the torsion housing. The pump will not have to lift fuel since it'll still below the bottom of the tank. And with a 100 micron filter it shouldn't be to restrictive.

Also you make a good point, the pump wire is only 1 wire if I decide to keep it up front.

I was originally thinking of that 5 micron filter because I have the exact same unit on my bug, but as an after pump filter on a carb turbo deal. I was thinking it would be nice to run the same filter on both so they use the same replacement filter.

[sideshow]

Some of my thoughts if you have the tank apart, what I noticed when doing my RBV is that FI ford uses a little red “duck lip” return hose end. I would assume this is a check valve and should help in aeration. A random image search return the same enough found on a full sized.

http://shop.broncograveyard.com/19-Gall ... nfo/30383/

http://shop.broncograveyard.com/images/ ... fmsu4b.jpg