Foxbody Fuel Rail Feed/return Questions

MileHi91LX · Sep 4, 2016

Im in the middle of a rebuild and am ditching the stock fuel rail and regulator. I've read conflicting or confusing Intel on the feed setup. Do I need to run a Y block and feed each rail independently or can I feed one and attach to the other with a crossover line? My original thought was I come into the passenger rail with a -8 feed on the backside of the engine, crossover to the driver side fuel rail on the front, come out the back of the driver side rail with -8 to a regulator, then run a -6 return to the tank. I would mount the regulator on the passenger side strut tower. Will that work or am I all messed up here? Also, do the feed and return lines have to be routed together? I've read that the regulator can't be mounted on the firewall per NHRA rules but can the fuel lines be attached to the firewall? One of my goals is to make this look clean, but I don't want to do something and be in violation of a rule I'm not aware of. Any input would be appreciated!

jrichker · Sep 4, 2016

How much HP are you planning to make and what is the intended purpose for the car when you finish?
Is the car going to be naturally aspirated or pressurized induction?
Is it going to use NO2?
Is it going to be race car only, street/strip, Street only, show car or closed course road race?

MileHi91LX · Sep 4, 2016

I'm planning on 550 crank HP. I'm running a Procharger on a stock block, 347 forged Eagle stroker. The car will be fuel injected and the ECU will be Holley HP. It will be a street-strip primarily, road course as we have one locally but not until I have money for better brakes.

jrichker · Sep 4, 2016

MileHi91LX said:
I'm planning on 550 crank HP. I'm running a Procharger on a stock block, 347 forged Eagle stroker. The car will be fuel injected and the ECU will be Holley HP. It will be a street-strip primarily, road course as we have one locally but not until I have money for better brakes.

The stock block will split right down the lifter valley at that power level.
The stock blocks are thin wall castings and the max HP for reliable power is somewhere it the 450 HP or less range.
You better start by saving your money for a Dart or other race engine block with thick casting and 4 bolt mains.

MileHi91LX · Sep 4, 2016

I know a lot of folks who have ran that power level with a stock block and been fine. I will run it until it splits. Any ideas on the fuel setup?

MileHi91LX · Sep 4, 2016

I should add that I'm in Denver so I will be limited on HP.... I doubt I will be much more than 400-425 RWHP

mikestang63 · Sep 5, 2016

at that power level you are fine with the factory rails and lines. Plenty of guys running them with well over 400rwhp including me.

MileHi91LX · Sep 5, 2016

But did I have the fuel flow routing correct in my initial post?

2000xp8 · Sep 6, 2016

MileHi91LX said:
I should add that I'm in Denver so I will be limited on HP.... I doubt I will be much more than 400-425 RWHP

Save your 2 grand and spend it somewhere else.
The stock system will support over 500rwhp with 42's and a gss340 walbro pump.

MileHi91LX · Sep 6, 2016

Thank you. Does anyone have insight on the fuel routing example I used in my initial post?

MileHi91LX · Sep 6, 2016

All of my harnesses are shot and they're 24 years old. Even if I fix the broken clips and bad wires where will the next issue pop up? I am pretty sure my computer is jacked up too. By the time I replace all of that, buy and calibrate a MAM and burn a chip I will have over a grand tied up. At that point I feel it is advantageous to go with a new ECU system and ditch Mass Air.

2000xp8 · Sep 6, 2016

I think everyone mounts it to shock tower and lets the regular dump the fuel back from there. That's what I did.
#8 up and #6 back.
I went down opposite sides with the return and feed, I don't remember why, but I think it was easier that way.

I have a fuel system and personally I wish I had run it without one to see if I really needed it. Original plan was a whipple, but after I drove it, I realized I probably don't need the extra 100hp, 500rwhp is enough.

You are going to have headaches regardless of how you set it up, aftermarket or fix what you have. If you think simply changing harness's adding a fuel system and going to a standalone is going to make life easier or somehow cheaper, IMO you are wrong. You may land up with the most expensive 400rwhp setup out there.

BTW, everyone's harness's are 25 years old and need a little TLC.

MileHi91LX · Sep 7, 2016

I read a few of your posts and it sounds like you spent a fair amount of money. Why would you want to use 25 year old wires to run the engine?

2000xp8 · Sep 7, 2016

MileHi91LX said:
I read a few of your posts and it sounds like you spent a fair amount of money. Why would you want to use 25 year old wires to run the engine?

Most fox wiring issues are either self inflicted or done by a previous owner. Other than the headlight switch, there aren't many major wiring issues with these cars.
If you are worried the real ford wiring diagram book is $15 at helm inc. If you can read it, you can trace what you need.

You speak like you are willing to put your life savings in this car, that's your business, but IMO, that is crazy.
Do what's best a little at a time.
To necessitate a fuel system you need to cross 500rwhp, if you cross 500rwhp you split the block, you split the block you need a dart (and a crapload more of parts because they all get ruined).
Best case scenario, you need about $6000 on just the shortblock, worst case, with new heads cams etc, $12,000+.
You obviously don't have the brakes, which oddly enough should be way ahead of a fuel system.
So why not spend the money there instead of throwing it into something you really don't need, and no offense, probably are never going to need.
There's like a half dozen active members with street cars on this forum with dart blocks.

None of that money includes a trans, a rear, a suspension that puts up with that much power etc.

If the car is low on gas, it will take like 30 minutes and $100 to switch to a gss340, or you could take the next 3 months and 2 grand, change the wiring and install a fuel system you don't currently need and hope it works right.

Easy choice IMO, since they both give exactly the same results.

Take the $2000, setup 94/95 spindles, cobra pbr's, rear discs and get some new wheels.
And set the car up so no matter what happens, you do NOT split that block, because it may be years before you drive it again.

I actually believe brakes and suspension should be done on a fox before you start adding power.
They add safety and value.

Just my opinions, you can take or leave it.
While harsh, I do have your best interest in mind.

MileHi91LX · Sep 7, 2016

I already have the suspenion, trans, clutch, rear, etc done from the last build except the front coil overs which are going in on this one. The wiring is a disaster from the previous owner who hacked it all to hell. I was chasing all kinds of electrical gremlins because of the security system he had on the car, which is gone, which was wired into everything, including the aftermarket kill switches for ignition and the fuel pump he had hidden in different places because it was a Chicago car and he didn't want it stolen. So perhaps you can understand my desire to rid myself of that mess entirely. The car currently has the big brake upgrade, 73mm single piston calipers and I never had an issue stopping the car before. I'm hoping to run in the 12s at Bandimere and unless I take the car to the salt flats for a top speed run I doubt it will ever go faster than whatever my trap speed is. I had some Mustang friends who have suggested that I convert the fuel to AN up front and run an aftermarket rail which would save some money and makes sense but I don't know. I've gotten so many suggestions/discouragement/condescending advice I am getting paralysis by analysis. I have a 255lph pump now and you've suggested a 340. If I don't increase the feed line diameter then how do i flow more fuel without increasing pressure? If my regulator is going to limit the pressure how does the 340 help? Also, I can read any blue print, schematic or wiring diagram you put in front of me so that is not a problem.

2000xp8 · Sep 8, 2016

Ok, how about this, i'll simplify it.
What problem is a fuel system solving?

A gss340 is a high pressure 255lph pump. Will support over 500rwhp. If you already have one, you don't need one.
Does the car run now? Does the pump prime? If so, I don't see the issue with the wiring.
Just get an aftermarket regulator like kirban that mounts to the rail and use 42lb injectors.
Let's just say the wiring to the pump is messed up (meaning you can not fix it), what the hell does that have to do with a fuel system?

73mm calipers are worthless. 2 stops on a road race track and you will be in the dirt.
They are like 5mm bigger than stock brakes. And yes I've had them. The fault in stock brakes isn't they don't stop, it's that they don't stop consistently.
You said in your first post you didn't have the money for good brakes, that is why I suggested you put the money there.

Sounds like you really want or think you need a fuel system or think it's going to solve some problem, so by all means do it. If I was in yours shoes, I wouldn't even be considering the idea.
But that's just an opinion.

MileHi91LX · Sep 10, 2016

Ok, there's a Mustang salvage yard near me and I can get a 94-95 front spindle, rotor and caliper set for $300. If I can also get the back set up at a reasonable price how do I address the longer axles? Are there any other things, other than getting 5 lug wheels, that I should be thinking about? Will I also need a different master cylinder and brake bias regulator?

Davedacarpainter · Sep 10, 2016

Let's get our brake guru's attention for that question @Mustang5L5 , help the man out brother.

2000xp8 · Sep 11, 2016

MileHi91LX said:
Ok, there's a Mustang salvage yard near me and I can get a 94-95 front spindle, rotor and caliper set for $300. If I can also get the back set up at a reasonable price how do I address the longer axles? Are there any other things, other than getting 5 lug wheels, that I should be thinking about? Will I also need a different master cylinder and brake bias regulator?

$300 is a bit steep for the spindles, but it's been years since I priced them, so that may be the new going rate.
I always thought they were valued around 150.

For the rear axles you buy fox length 5 lug axles (28 spline if you aren't changing the carrier), then north race car brackets.

You need the stock proportioning valve plug after you gut it.
A proportioning valve for the Passenger side firewall.
I prefer the 93 cobra master cylinder without the booster (some people like the booster, but I think it's far from necessary).
Stack of washers or new front ball joints.
E brake cables.

Me personally, I wouldn't take or buy the rotors or the calipers with the spindles, i'd get 2 piston pbr's from a cobra, bullet etc..
Then buy brand new cobra rotors for the front.
In the back, i'd just use v6 or gt rear rotors and calipers, only difference for a cobra is they were vented.
You'll need SS brake lines that go from fox on the body side to pbr on the brake end. Should be like $100.

Shop around for all it (that's part of the fun).
Should come in around a grand.

Edit: make sure you only use 94//95 spindles
And looks like you are going to get wacked on the pbr dual piston cobra calipers, prices used to be like $250 a set, loaded with pads, brackets etc, now they are like $400.

MileHi91LX · Sep 11, 2016

Thanks for the info! I'm struggling to find brake caliper specs for a 94-95 GT/V6. On LMR the kit to rebuild OE GT/V6 calipers has provisions for 4 Pistons, I'd assume 2 per caliper. So are the 94-95 OE calipers 2 piston or did they come with single piston? Also, I read a few articles in the rear where you can modify the stock brackets, flip sides and mount inboard. Is that a safe way to make the stock brackets work?

Foxbody Fuel Rail Feed/return Questions

MileHi91LX

Member

jrichker

StangNet's favorite TOOL

MileHi91LX

Member

jrichker

StangNet's favorite TOOL

MileHi91LX

Member

MileHi91LX

Member

mikestang63

MileHi91LX

Member

2000xp8

MileHi91LX

Member

MileHi91LX

Member

2000xp8

MileHi91LX

Member

2000xp8

MileHi91LX

Member

2000xp8

MileHi91LX

Member

Davedacarpainter

Chicks can make things hard if they’re inspired...

2000xp8

MileHi91LX

Member

Similar threads

Foxbody Fuel Rail Feed/return Questions

Member

StangNet's favorite TOOL

Member

StangNet's favorite TOOL

Member

Member

Member

Member

Member

Member

Member

Member

Chicks can make things hard if they’re inspired...

Member

Similar threads

Privacy & Transparency

Privacy & Transparency