newbie mustang owner fueling questions

Discussion in 'Fox 5.0 Mustang Tech' started by mrlilguy157, May 10, 2009.

  1. hey guys. I've been lurking the forums lately and i just bought a 1991 mustang lx 5.0 with a vortech v1 t trim blower, e303 cam, gt40p heads, ford racing 1.6 rockers, cobra efi manifold, 30lb injectors and C&L MAF housing, 70mm TB, new aluminum radiator, alternator, edelbrock water pump, holley 255lph in tank fuel pump, aluminum harmonic balancer... etc etc.

    this car also has an adjustable fuel pressure regulator with the fuel pressure gauge on the front raintray area, as well as a J&S Electronics ultrasafegaurd computer with the wideband monitoring....

    the trans is a TREMEC 5 speed, and the motor is fresh, i'm pretty sure built.

    from what i've learned the 5.0's before 1993 (This is a 1991) had forged pistons. are they legit? how are the rods and crank? etc.

    supposedly this car put down 521whp, but its tuned at a conservative 430whp/390wtq right now, on 8psi.

    several people i've talked to think that the injectors are too small for either numbers. my cousin is a big lightning buff, and i was thinking about just grabbing a set of his 42lb injectors that he's got laying around, and the lightning 90mm maf. does that swap right in, correctly?

    in doing that, would the car drive just fine swapping in the larger MAF which is calibrated for larger injectors? I think this is the first change i'm going to make to the car.

    please inform me. I'm new to the 5.0l mustang platform, though i know forced induction and fuel injection very very well. i'm used to building ridiculous 4 bangers.... but I'm excited about the transition into REAL power from a blown v8.

    I'd love to chat with someone friendly and extremely knowledgable. i can talk cars all day long, I just need to know what I need to look into as far as tuning the thing. I pick up the car next weekend and its coming with a fat binder of receipts and pictures from the build up.

    get back to me!

    jonathan martin

    Attached Files:

  2. use this for injector size


    and the stock forged pistons are pretty good

    actually in most cases the pistons and rods will last longer then the stock block

    i would be surprised to see your car dyno at over 500rwhp with stock block and internals...
  3. o and congrats on buying the car, it looks great!

    be careful with it! lots of power
  4. OMG Sweet ride dude. I wanted to tag along and c if I could learn a thing or 2 about tuning also. Just got my fox too.
  5. I'm not familiar with the "J&S Electronics ultrasafegaurd", but it looks like a piggy back system to the stock ecu?
    The J&S setup is for retarding spark advance based on feedback from a knock sensor?

    If you have access to the tune settings in the ecu, then you can run the 90mm LMAF and 42's. Many folks have done this, and the LMAF is still one of the best meters available to us.

    Does the car run the factory ecu?
    Is there a chip installed in the back of the ecu?
  6. I have a comment to make about that link...

    That site has some MAJOR issues.
    The moderator who authored that thread, is clueless. I cannot tell you how many times I have corrected something stupid he has stated.
    He has told members not to waste time pulling diagnostic codes.
    He has told members that bearing clearances would wear in.
    (I can provide links/evidence)

    Notice at the end of the above linked thread, a question was asked by 'dudeboy'. No response from that Eagle guy, because he doesn't know.
    (btw, I go by dudeboy there... that is me)

    If you posted a link on AFM to another site, the staff would edit your post to remove the link. They don't allow people to link to other sites, so why would you link to their site.

    My opinion,
    If you want to learn REAL tech... AFM is the very last place you should go.
  7. :rlaugh::rlaugh:

    Vri kills me.
  8. Link removed, image inserted....just to keep the masses happy. ;)
  9. First off congrats on your first mustang buy, not many fox body's can pull off the yellow look. I will let you know a buddy of mine that rebuilt his motor and kept the the rods and piston had a 400 hp and a little under 400 pounds of TQ supercharged system and it was a 1990 fox body. His motor never had an issue so the stock forged rods and pistons can take a beating. And please keep this site informed on what you do for a tune I am curios about what you learn is the best way to tune it.