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Discussion Starter · #1 ·
right now at 5.5 to 6 psi i have 360 HP and 380 LBS to the wheels and it feels really fast but i can go as far as 11 psi for my next upgrade. after that i'll have to re-do the tranny and if the centerforce dual friction won't cut it then it will have to be changed too. i will also do an inline fuel pump.

will the stock fuel rails handle 450 HP or more to the wheels?

thanks

luis lopezFFR4031
 

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I've read that they can handle somewhere in the 350-400 hp range. If you are thinking about going to 11psi I would definitely get bigger fuel rails because you don't want to lean out at that boost level. The stock rails are pretty damn small. When I went to 9 psi on my Mustang I went with bigger rails just to be safe. You also get some future expansion room with bigger fuel rails.
 

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We took the stock fuel rail and modified it by drilling open the front end of each side rail and silver soldering JIC (AN) fittings on so that we could use stainless braided line to feed each rail independently. This eliminates the restrictive 90 degree entry into the stock rail and allows the supply lines to be enlarged. Running 9 psi and will be going to the dyno this spring to see if the effort was successful. The thing runs pig rich right now.
 

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Luis

There was an article in Super Fords magazine a couple of years back where Kenne Bell did testing on fuel rails and fuel pumps. They found that the stock rails would flow well enough up to about 600HP. I will try to find the article. From what I remember the bends and the fact that the regulator is on the back of one of the rails and the inlet is on the front of the same rail started to create pressure differences between the two rails. JasonD's mod described above would definitely help that.

E-mail Mike Ritter (BIGMIKE) and ask him if he is still running the stock fuel rails on his twin turbo. Last I heard from Mike he was well over 500HP to the wheels on about 10 psi.
 

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OK

I just found a piece in the Kenne Bell catalog that says, quote....

"Our pressure transducers tell us that there is a mere 1-2 psi loss in a stock fuel line from tank to fuel rails with 40 lb injectors - and the stock fuel rails are perfectly adequate to 600 HP" "One of the advantages of an in house fuel flow bench and dyno is that you discover that replacing the stock fuel lines and fuel rails are not neccessary up to 600HP."

So crank up the boost and spend the fuel rail money somewhere else !
 

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Discussion Starter · #8 ·
i have 308 gears and 315/35 nitto DR on 11" wheels. traction is not a problem. i'm running really rich right now and i could have squeezed another 30-40 HP if i would have leaned it out. i just wanted to stay on the safe side.

i guess if i want to go 10-11 psi i will have to do new rails again to be on the safe side. i don't know about that 600 HP. that sounds like living on the wild side to me :eek: all i WANT is 440-450 to the wheels. all i really NEED is what i have right now. i'll probably do rails and inline pump. that should do the trick.

thanks

luis
 

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Luis

Sorry if I wasn't clear above. You do not need to change fuel rails until you exceed 600 HP. At your projected power level (450RWHP) you will be just fine with the stock rails.

A good in tank pump combined with an in line pump would be a good idea though. Plumb a fuel pressure gauge into the end of one of the stock fuel rails and watch the fuel pressure the next time you go to the dyno. If the pressure holds steady and doesn't decrease at high rpms and boost then your fuel system is adequate to supply enough fuel to the motor.
 

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Discussion Starter · #11 ·
mike

i think that i will up the boost a bit and go to the dyno and watch that fuel press gauge. i was going to change the springs on the wastegates to .8 bar from .6 bar...... now that i'm thinking about this.... i think i have .4 bar instead of .6 bar.....

.4 bar = 5.88 psi
.6 bar = 8.82 psi
.8 bar = 11.76 psi

my gauge reads close to 6 psi all day long :rolleyes:


this changes everything. if i go to .6 bar then all i'm doing is going up close to 3 psi and i don't really have to change so many things. i could stay with my set up and turn up the fuel press and call it a day... do i make sense?

thanks

luis
 

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Luis

Do you know what your current A/F ratio is? From what I know about Turbos you should be in the 11.5:1 to 12:1 range to be safe. My A/F ratio is right at 11.5:1 with my Kenne Bell.

If you are using a mass air set up you shouldn't need to change the fuel pressure, the computer should increase fuel based on the extra volume of air. If you are using an FMU then you will have to fuss with it.

BTW I love your Turbo set up, let us know how you get on with the higher boost!
 

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Luis,

I ran with the stock rails for a while. I was making a little over 500 hp at the wheels. Never had a problem. Just put it on the dyno and watch the A/F. Also watch the fuel pressure at the end of the pull to make sure it won't go down. Be careful on long 4th gear pulls with less than 1/4 tank though. Can run out of gas when it all runs to the rear of the tank and go lean.

When I moved up to the R block stroker motor with the Canfields, etc I broke open the wallet and put in an Aeromotive inline pump, rail, regulator and braided lines. Cost was around $1,000. I keep thinking I will eventually want to turn up the boost past 10 psi, but every time I drive the thing like it is now I catch myself wondering WHY?? :confused: :D

Later,

Mike
 

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A couple years ago, some of the Mustang guys
came up w/the notion that the SN95 fuel rails
had a slightly larger ID than the Fox rails.
If anyone thinks they are on the ragged edge
of their stock Fox piece, I will take this
opportunity to shamelessly plug the clean SN95
fuel rails that I will not be using. $25+shppg.
Stock regulator included.
Good luck, Matt
 

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Discussion Starter · #15 ·
bigmike

did you have 500 at the wheels with stock rails? did you have a 255 l/h high pressure intank fuel pump(or what size) without an inline pump? what size injectors? what size lines?

Mike N.

my A/F after 3500 rpm's is lower than 10 to 1 its about 12 to 1 before then. if i can get it to be 12 to 1 all the way to 5800 i think i would gain about 30-40 HP more.

matt

i haven't heard that about the SN95 but if its true then that could be an option(no shame in the plug in if its going to help, thanks). also i've heard that the explorer rails are a bit better too... any comments on that?

also... what is the reason why an inline pump helps the fuel delivery?

thanks

luis
 

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Luis

You should pick up some power getting your A/F ratio back in the 12:1 range. What you have sounds very rich. That thing should really sing.

The in line pump is really just a booster pump you won't get anymore total fuel volume except at higher pressures. If you don't see your fuel pressure dropping off at redline you don't need the extra pump. BTW Kenne Bell has a nice "boost a pump" set up which increases the voltage to the pump under boost only, that you may want to consider instead of the extra inline pump. You can normally find boost a pumps cheap on the Mustang forums.
 

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Luis,

My car dynoed at 460 rwhp with the factory fuel rails, the FFR supplied lines, a 255 lph intank pump and 38 lb injectors pushing 9-10 psi. Fuel pressure was set at 40 psi with the vacuum line off. That was with the ported stock heads. Then I put a set of Brodix ST-R heads on the motor and bumped the FP to 42 psi. Although I did not dyno the new combo, the change in performance was noticeable. I am sure the heads were good for at least 40 hp. I ran it that way until I pulled the motor out without any problems.

Are you using the stock EEC IV tune? If so are you decreasing the base timing?

Good luck,

Mike
 

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Discussion Starter · #18 ·
i do have the stock computer and i have an MSD BTM and its set at 1/2 degree/psi. i don't know where the timing is. the guys at mustang specialties here in south fla. did the dyno tune and they just went by ear or something. they said that the car came in running super extra rich and they brought it up from 260 to the wheels to 360 to the wheels.

i do have holley systemax heads. they have been O-ringed for boost purposes. forged piston(flat tops) and eagle I-beam rods with ARP bolts all over the place. i think the comp. should be 9.3:1 or something. my lines are 3/8(-6)from the tank to the rails and 1/4(-4) back to the tank.

i don't think that 3 psi of boost will change much. should i just go for it? if i do... i won't get on it untill i hit the dyno.

luis
 

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If you are going to take it back to the dyno, then yes, turn it up and see where the a/f is. You should be ok.

Just make sure that it is pointed where you want to go cause it will get there fast. You may need to invest in bigger brakes. :eek:

Mike
 
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