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fueling the 4.6

jeepnuts311

NAXJA Forum User
Location
Atlanta, Georgia
hey all,
I am pretty close to doing a 4.6 stroker in my 1990, i am most likely going with the golen 4.6 and i have been told by chad golen that i will need an adjustable fuel pressure regulator. i found a holley one that will work for my jeep for about $160 at the LAPS, are there cheaper ones? also, will the stock fuel pump be up for the job? will the adj FPR allow the extra fuel for the 24lb injectors?

thanks
-tim
 
I am running a 4.7L I built several years ago. I run the Ford injectors with no fuel pressure regulator. I did add a MAP sensor adjuster to tweak the mixture for emissions. I was actually running a touch rich.
 
old_man said:
I am running a 4.7L I built several years ago. I run the Ford injectors with no fuel pressure regulator. I did add a MAP sensor adjuster to tweak the mixture for emissions. I was actually running a touch rich.

thanks, what computer do you have? i am working with a renix.

-tim
 
Standard Renix. I have run both manual and automatic computers & trannies.

The key to a good stroker is getting the quench height correct. I am running in the mid to high 9's and can run regular gas. I decked the block around .020 - .030". I can't remember which anymore. I also run the thin performance MOPAR head gasket.
 
old_man said:
I run the Ford injectors with no fuel pressure regulator.

time for a stupid question, are you saying you did not upgrade and are still running a stock FPR, or you have no FPR at all?

-tim
p.s. seriously not being a smart a$$, just wondering.
 
I am running a stock FPR with LT1 injectors. I wish I had an adjustable FPR but not with a 97 :(
 
I am running a 4.6 stroker with the 24lb injectors and the stock fuel regulator. No problems so far, plenty of power but maybe a tad rich, gotta get the MAP adjuster built sometime soon. BTW mines a 88 renix system.
 
I would leave the injectors stock at first. Clear the computer and let it learn how to fuel the big motor. Drive it for a bit and see how it feels. The computer may very well compensate for the extra CID on it's own.
If you have a dragstrip close at hand take her there before and after any changes. It's just to easy to let wishful thinking take over and be blinded to the fact that no real improvement was made or even a lost of HP.
 
badron said:
I would leave the injectors stock at first. Clear the computer and let it learn how to fuel the big motor. Drive it for a bit and see how it feels. The computer may very well compensate for the extra CID on it's own.
If you have a dragstrip close at hand take her there before and after any changes. It's just to easy to let wishful thinking take over and be blinded to the fact that no real improvement was made or even a lost of HP.

A) Renix computers do not "learn" anything. They have no memory, they start fresh every time you turn the key on.

B) the only way to know if you are running lean at WOT (the only time you'll really ever use the full injector pulse width) is to buy or borrow a wide band o2 sensor. What you'll find with the Renix is that all you'll really need is 24 pound/hr injectors. This will put you very close to 13 to 1 at WOT, a very safe and cool mixture. The adjustable MAP allows some fine tuning of this, but it's probably close enough on it's own. Running at a dragstrip will tell you about HP improvements, but will tell you nothing about whether you are runnign too lean at WOT.
 
onetallmj said:
I am running a 4.6 stroker with the 24lb injectors and the stock fuel regulator. No problems so far, plenty of power but maybe a tad rich, gotta get the MAP adjuster built sometime soon. BTW mines a 88 renix system.

ditto my 4.6 on an OBDII system, and 20 mpg...
 
i am between 4.6 and 4.7 on my 40 over stroker. RUnning the 24lb four brothers racing injectors (scored 8 on ebay for $100). and she runs great. I built the adjustable map but never installed it, no need too. the extra safety of running a tad rich of preferred over running my 2000 dollar power plant lean and over heating it. run a little rich and cool is like an added insurance on it.

on gas mileage, i couldn't tell you, i can't keep it on the pavement long enough to get an accurate reading.

john
 
jeepnuts311 said:
hey all,
I am pretty close to doing a 4.6 stroker in my 1990, i am most likely going with the golen 4.6 and i have been told by chad golen that i will need an adjustable fuel pressure regulator. i found a holley one that will work for my jeep for about $160 at the LAPS, are there cheaper ones? also, will the stock fuel pump be up for the job? will the adj FPR allow the extra fuel for the 24lb injectors?

thanks
-tim

You don't need an adjustable fuel regulator. The stock 39psi unit will do fine and the chances are, you won't need anything else other than Ford 24lb injectors. You could build a MAP adjuster but I suspect you'll probably have the voltage close to stock (5.0v). The stock fuel pump will do fine.
My set-up? Stock fuel pump, stock fuel pressure regulator, Ford 24lb injectors, MAP adjuster set at 5.25v, excellent emissions, average 20mpg despite lead foot (can get 25mpg if I drive like grandma), and A/F mixtures right on the money.
___________________
1992 XJ Laredo 4-dr - 201k miles - 27k miles on 4.6L HO Stroker
AX15, NP231, D35c, D30
small.A9DFB5LA1GZW1.jpg

270hp@4950/327lbft@3750, 1/4 mile = [email protected], 0-60 = 5.6secs :D
Websites - Jeep 4.0 Performance, 4.6L Stroker Build-Up, Dino's Jeep Tricks
 
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