24# Injectors

Discussion in '1996 - 2004 SN95 Mustang -General/Talk-' started by j966er, May 22, 2014.


  1. j966er

    j966er New Member

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    The builder of the performance motor I'm looking at recommends installing 24# injectors . Would I have to upgrade my fual rails an fual pump ? Also would I need to get a dyno tune or could bama write me a new tune for the hand held tuner I bought from them.
    #1
  2. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    24# injectors will fit right in. You will need them either matched to your maf or have a fresh tune written
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  3. adamv7010

    adamv7010 Member

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    I've been curious about this too...on basically stock cars, would 24lbs be any gain over stocks. Obviously a tune would be necessary, but what maf would be suitable?
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  4. Three50won

    Three50won Member

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    24s will gain you nothing on a stock Mustang GT to even a Mustang GT with all bolt-ons. If anything, you'll run rich and lose power. I ran 24s on my all bolt-on GT and monitored the fuel through a scanner and my fuel was way rich at part throttle and WOT. So 10s are your best bet. You won't need 24s until you either have a lot more compression and/or ported heads/aftermarket cams.
    #4
  5. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    with either a properly calibrated maf or a tune for the injectors, the vehicle will not be rich. I will also agree that they are not needed on a bolt on car though
    #5
  6. Three50won

    Three50won Member

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    I had a tune and my trims went super rich. I then tried 24s with a MAF sensor calibrated for them and it still went rich. Then I tried the MAF sensor and also tuned it and it was rich. Ran the 19s and it was fine. I monitored my trims in real time on a professional scanner. Even when I adjusted the fuel through my tuner it still was rich. Nothing I did with the 24s worked. And this was on a full bolt-on GT.
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  7. logancamp

    logancamp Member

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    I'm ordering 24# injectors asap I just installed patriot stage 2 heads comp 262 cams an a port matched professional products lower intake I got full bolt-ons I can hardly move my car with out it getting all choked up an starved for fuel
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  8. restomod66

    restomod66 Member

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    I'm really unsure of why your builder would recommend the larger #24 injectors on an otherwise stock motor? Unless you have increased your motors need for fuel through modifications you absolutely don't need them, and there will be 0 performance gains whatsoever. The fuel system on a GT has a fair amount of growing room (bolt-ons) before you need to start seriously upgrading it. All bets are off if you decide to go forced induction because that would obviously necessitate such upgrades.
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  9. j966er

    j966er New Member

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    Who said stock motor ? The motor I'm having built is a 3.8 block bored an stroked to 4.3 with performance, cam stage 2 ported heads an all the other good stuff that I'm to lazy to list. So this motor is fare from stock.
    #9
  10. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    were talking about a six banger :shrug: 19's are plenty
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  11. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    then your tune needed adjusting. Maf transfer function was off
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  12. Three50won

    Three50won Member

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    Perhaps. Wouldn't be the weirdest thing that has happened to me...thanks for the info!
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  13. sneaky98gt

    sneaky98gt Mustang Master

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    Actually, I doubt that. Let's do the math.

    4.3 liters of displacement. 6000 rpm. And 100% volumetric efficiency (I could be a little over here, idk). Do the math, and it comes out to displacing around 2047 pounds of air per hour.

    Throw in a 12.5 AFR to that number, and you need 164 pounds of fuel per hour.

    Divide by 6 cylinders, and you need 27.3 pounds per hour (per hole).

    I am not at all familiar with the 6 cylinder cars, but if he can actually displace 4.3 liters, and then fill those cylinders (he did say heads and cam), then I'd recommend 30 lb/hr injectors over 24 lb/hr. My estimates are high, and 24 lb/hr would probably work. But it's significantly better to be able to inject all of the fuel needed for a given stroke in a SHORT period of time (to take advantage of the port air velocity), versus just having them run at 100% duty cycle like the 24's likely would be at higher rpm.
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  14. Three50won

    Three50won Member

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    My bad, I automatically thought it was a SOHC 2V 4.6...
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