24 Lb Injectors

Discussion in '1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-' started by John Dirks Jr, Dec 22, 2013.

  1. I was at the pick and pull today and I think I spotted injectors I can use. I want to confirm first. These are in a 32 valve V8 1997 Mark VIII. They are the blue injectors.

    Are these the 24lb injectors that will work with my 92 5.0?



  2. Yes but with your combo you dont need them.
  3. Ok. But to be sure. I will have mild ported GT40 heads, explorer intake and 65mm TB, stock cam with 1.7 roller rockers, exhaust, etc...,,

    Are you saying the 19lb injectors will be enough for this setup? Nothing to gain with 24lb injectors?

    Thanks because if there's nothing to gain, I wouldn't wanna waste the money on them. Cheap though, at $72 for the full set of 8.

    I'm aware if I did go to 24lb, I would need a matching MAF.
  4. Same sEt up I have. 19s are just fine
    f8tlfiveo likes this.
  5. Bigger injectors do not create additional power, all they do is supply the fuel. If your injectors are too small you run the chance of running lean at full throttle. In your case 19 lb injectors are fine.
  6. Thanks for the info friends. I'll skip the 24lb injectors.
  7. stock injectors can support 280-300 hp all day long. I run them with an explorer top end
  8. If they are cheap, grab them

    I've sold mark 8 injectors on ebay easily for good $$$$$
  9. Is $9 each or $72 for the set of 8 cheap enough? How much would they go for on ebay?

    I might get them in case I need them in the future. If not, I could always sell them.

    There might be a mild super charger in the future plans. If that idea develops into fruition, then would I need 24lb injectors?
  10. 72 is pretty steep. You won't make any profit at that price. Any supercharger is going to require36# or better injectors. Pass.
    #10 stykthyn, Dec 23, 2013
    Last edited: Dec 23, 2013
    f8tlfiveo likes this.
  11. Man I would take that whole motor. As far a 4.6Ls go, that's one of the better ones.
    88LX5.Oh likes this.
  12. IMHO 24 lb injectors are a waste of money. I would not buy anything under a 30lb. 70$ seems a little expensive for junkyard injectors.. Maybe 20-30$
  13. Damn, that's expensive.

    I think I was paying $10/set and selling them on Ebay for $75-100ish.
  14. Yep,. you can buy them all day long for $50 for a set on the boards. I also agree that they are kind of a waste. You might as well get 30's as they give you room to grow when you decide to add a blower or change your setup. Just dial down the FP to compensate or get a tune.
  15. If buying new, i agree with you. Go with 30's over 24s and get a tune to make sure everything is dialed in correctly

    If going used injectors, 30's are tough to come by. They did come on supercoupes for a few years. Most people on the boards upgrade their injectors needlessly all the time. A stock-headed car with an explorer intake and exhaust does not need more than 19#ers. IIRC, the stock 19's are good for around 300HP. His combo might be near the borderline of needing injectors.
  16. 19s will hold a gt40 combo all day. If he does a cam swap and springs for better heads then yes 24s would be in order. Regardless of porting I dont see a streetable gt40 combo requiring a bigger injector without a power adder.
  17. Ive never tuned a heads/cam/intake 5.0 that didnt max out 24lb injectors

    19lb injectors will never support 300hp its physically impossible

    24lb injectors will cause lean out on any healthy running HCI stock bottom 302 making only 310rwhp, i know because i deal with it day in and day out, the biggest mistake most fox owners make is spending the coin on 24s absolute junk NEVER buy 24s

    The DOHC injectors probably have a split pattern, its not ideal to hose down the port walls with those type injectors in a pushrod.

    30s will never support a supercharged setup

    all the info is here

  18. No offense, but I suggest you change professions with that kind of advice. There are hundreds if not thousands of guys running 19's and around 300 hp. 24's can easily support 325...

    Jrichker posted this several times

    Injector HP ratings: divide flow rating by.5 and multiply the result by the number of injectors. This uses a 100% duty cycle. These ratings are for naturally aspirated engines.

    19/.5 = 38, 38 x 8 = 304 HP
    24/.5 = 48, 48 x 8 = 384 HP
    30/.5 = 60, 60 x 8 = 480 HP

    The preferred duty cycle is about 85% maximum, so for a safety factor multiply the final figure times .85.

    304 HP x .85 = 258 HP
    385 HP x .85 = 326 HP
    480 HP x .85 = 408 HP

    Remember that the above ratings are at 39 PSI. Increasing the pressure will effectively increase the flow rating. Example: a 19 lb injector will flow 24 lbs at 63 PSI, and a 24 lb injector will flow 30 lbs at 63 PSI.

    See http://users.erols.com/srweiss/ to get the calculators used in these examples.
    stykthyn likes this.
  19. Will a slightly higher fuel pressure help 19's give a little more if a setup justifies it? I already have the Kirban adjustable reg on there.
  20. If you find you are leaning out WOT you can cheat and dial the pressure up.