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FFCobra Captain
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On my Mustang project, I’m going to run a fast EFI stack setup. Looking for opinions or experience running the pressure regulator back by the tank.

I’ve got the fuel system laid out and am using a LS filter/regulator and have it mounted back near the fuel tank. A real short line for the return back to the tank and only one line to the front. Then I’ll run a splitter on the firewall and feed the fuel rails.

I’m using -6 fuel lines and fittings so I will have enough fuel for sure.

I can’t run a crossover at the fuel rails (the distributor interferes). If I could set it up with a more typical regulator setup (regulator after the fuel rails) I would probably do that. But since I can’t, I don’t see a downside to the way I’m doing it.

I read people saying that the pressure can fluctuate with so much line between the regulator and the rails. But this is in a 305hp 302 motor so it’s not a monster in terms of power.

Doing this mainly for simplicity of the fuel system (only one feed line up front) and I’m able to keep one more thing off the firewall.

Anyone setup their roadster like this?



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Don't believe no one has had an opinion on this yet. So I'll give it a bump and my non expert look at it. First there should be a flow chart some where that would tell you the max volume through the -6 line at a given pressure. That would tell you if your set up will work in worst case conditions. I would think you'd be ok with it as is considering your plan. The only down side I think of would be access for adjustments/repairs.
 

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FFCobra Captain
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Discussion Starter #3
Thanks for the bump.

Access for repairs won't be an issue...I have a lift and it will be easy to get too.
This regulator isn't adjustable...constant 58psi.

If I needed to change plans later on because an adjustable regulator is required, then I could change things up without too much hassle.
But I really would like to keep the system simple if I can make it work.
 

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Thanks for the bump.

Access for repairs won't be an issue...I have a lift and it will be easy to get too.
This regulator isn't adjustable...constant 58psi.

If I needed to change plans later on because an adjustable regulator is required, then I could change things up without too much hassle.
But I really would like to keep the system simple if I can make it work.
First post on the new forum style so i'm trying to find all the buttons! I have a FAST efi stack set up on my car but I mounted the regulator on the fire wall close to the fuel rails. Without going out to the garage I believe I have a 5/8" feed and a 1/2" return and ran two lines. Did it that way for no particular reason except ease of access for adjustment. In my experience I have seen fuel pressure fluctuations with a regulator with no return like the old blue Holley type. Mine with the return line is dead on 45 psi all the time. It never fluctuates at all. I know because I have a dash mounted gauge which I cant seem to take my eyes off. Yours should work the same way mounted back in the rear. Mine is a hard line though. I have run similar setups as yours on boats with many feet of steel braided hose and haven't had any issues with fuel pressure swings.

Steven
 

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Thanks for the bump.

Access for repairs won't be an issue...I have a lift and it will be easy to get too.
This regulator isn't adjustable...constant 58psi.

If I needed to change plans later on because an adjustable regulator is required, then I could change things up without too much hassle.
But I really would like to keep the system simple if I can make it work.
I totally understand about keeping it simple, but if the regulator were to malfunction, and need repair, Murphy's Law says that there won't be a lift available.. Maybe you cold put an access panel in the floor of the trunk to get at it ??
 
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One problem with the regulator mounted that way is any air in the system will not be purged back to the tank. So it will have to be bled at the fuel rails or crank until the injectors purge it which can be a pretty long time. For many years Mercury ran a similar setup on boats and it was always a challenge to get them restarted if they ran out of fuel or changed the fuel/water separator and got some air trapped.
 

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Dan, all the OEM fuel injected vehicles I have worked on have the fuel pressure regulator mounted on the engine. Most likely this is for the reason Bobl mentioned above but there could be others. The regulator mounted close to the injectors will be much quicker to respond to pressure changes do to fuel demand on acceleration etc.
 

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I think that is a bad setup. You will have the fuel dead heading at the injectors, and no way to purge the air out of the lines, not a good idea with a stack system. Also your fuel pressure is too high for a Fast Stack system, I think that system is designed for around 43psi. The Fast system is finicky enough without trying to work around too high a pressure, and a fuel system the doesn't flow fuel properly.
 

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06 AN is perfect and will flow plenty. Good point above by Rich GRSC - you would need a non-bypass adjustable regulator and a gauge in the engine compartement to drop the 58psi to the pressure recommended by Stack I think - so you will just be saving the return line and fittings by using the rear mounted Corvette filter/regulator. Rear mount Corvette filter regulator IS is a return style system.
 

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Discussion Starter #10
I think that is a bad setup. You will have the fuel dead heading at the injectors, and no way to purge the air out of the lines, not a good idea with a stack system. Also your fuel pressure is too high for a Fast Stack system, I think that system is designed for around 43psi. The Fast system is finicky enough without trying to work around too high a pressure, and a fuel system the doesn't flow fuel properly.
Just saw your reply.
I haven't been able to get any information from FAST...their support for their Inglese system sucks.

I have the manual for the FAST XFI computer & wiring, but there's no mention of the fuel pressure needed for the stack. They don't have any instructions that tell you how to setup the stack system either.
Do you happen to know where you got that 43psi number from?

My assumption was that since their injectors and idle control valve are basically GM parts, then a GM regulator would work.

It's not too late for me to change things up. I can use all the parts I already bought and just use the mount I made for the GM filter/regulator for just a fuel filter. I'd just need to get more fuel line and an adjustable regulator from Breeze.
 

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I have a Borla Eight stack, the 43 # psi is from them, and is usually a standard for injectors. Inglese should have the pressure requirement in the manual. It is based on the injector, so if it's a GM based setup, then the pressure may be OK.
Good luck dealing with Fast. You need to talk with David Page. 901 375 3492
 

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FFCobra Captain
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Discussion Starter #12
I have a Borla Eight stack, the 43 # psi is from them, and is usually a standard for injectors. Inglese should have the pressure requirement in the manual. It is based on the injector, so if it's a GM based setup, then the pressure may be OK.
Good luck dealing with Fast. You need to talk with David Page. 901 375 3492
Thanks! That’s a huge help. I’ll call him on Monday and try to get some info.

I was out in the shop tonight. I laid out the feed line and have a plan for a return if it’s needed.


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From experience put all AN fittings/filters/regulator where you can easily get 2 wrenches on them for tightening/serviceability. I really had a tough time when I found fuel seeping from the Y that goes to the fuel rails as it was between the engine and the firewall due to lack of planning.
Also I agree unless it is really cramped the reg up high in the engine compartment is a good idea. When in doubt look how professional race cars are built
 

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Discussion Starter #14
Good luck dealing with Fast. You need to talk with David Page. 901 375 3492
I reached out to David via email with a bunch of questions and he got back to me promptly with a bunch of great answers. I can use the LS regulator, but I may still go with a firewall mounted adjustable regulator.

Thanks again for the lead.
 

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I reached out to David via email with a bunch of questions and he got back to me promptly with a bunch of great answers. I can use the LS regulator, but I may still go with a firewall mounted adjustable regulator.

Thanks again for the lead.
Glad you're getting some help, and hope it's all smooth sailing.
 
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