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SWITCHING from #30 to #42 pound injectors

6524 Views 3 Replies 3 Participants Last post by  Millusos
hi, this is me again,

do you know if a switch from #30 to #42 pounds injectors will give me more power, without changing other parts?, i will get my mass meter recalibrated for #42 pounds.

i thinking on getting aluminiums heads, on the future, thats why i switching injectors, but is this worth it now?

this are my mods:

88' Ford Mustang GT.
stock heads but port & polish,
1.6 roller rockers,
+40 sealed power piston,
z cam,
trick flow upper & lower intake,
high volume oil pump,
30lp injectors,
novi 1000 supercharger,
bbk 255lph fuel pump,
msd 6al,
jacobs ignition coil.
mallory distributor
70mm holley throttle body,
70 mm bbk spacer,
75mm mass sensor,
bbk 1 5/8 headers
aluminium driveshaft
a/c delete
smog pump delete
battery relocation kit.
i don't know the rear end, i think is stock,
car weights like 3250 lbs.
may be more stuffs, i don't remember.
1 - 4 of 4 Posts

I think you're making a mistake by installing 42 pound injectors. A bigger injector DOES NOT mean more power and can actually negatively affect your engine. Without the proper Air/Fuel Ratio you can't make full power, or even worse - you can destroy a perfectly good motor really quick! The first thing to consider is that it's the fuel that makes the power. For every amount of air you can squeeze into the cylinder, you must also have the proper amount of fuel to go with it. Too much fuel and you drown, too little and you start burning things up. It's that fine line that you're after, if only it was that easy.

All too often I see cars with huge fuel systems, for no apparent reason other than to jump on the band wagon. Don't get me wrong. If you're planning ahead that's one thing, and it is better to be too big than to be too small. The sad thing is when people are pushed into theoretical ideas of what they need. While with the proper Regulator or FMU (Fuel Management Unit) you can run a huge Fuel Pump, it is the injector size that is most critical. This is the one piece that should definitely be matched to the motor. For every Mustang running 11's and 12's with 42 lb. injectors, there is another running 10's with 24 or 30 lb. injectors.

Sure a 42 lb. injector will work with the right amount of fuel pressure, and the correct tuning device, but at what cost? Typically, idle quality and mileage are what suffer, as they can be tough to tune correctly. With many combinations a 24 lb. injector will work great by running a higher fuel pressure under load. This will allow your car to run properly, especially when not being pushed hard, which is very critical for a street driven motor. Huge injectors can be great on race only cars, but will be hard to tune around on a daily driver.

You didn't state any modifications to your block so i'm assuming that you have the stock 302 and your 30 pound injectors are PLENTY big for the mustang you have. You've got a decent combo of mods and will be better off with aluminum heads but shy away from bigger injectors unless you want to install an entire upgraded fuel system. Instead, get a Diablo Sport performance programmer or something like it and precision tune your ECU to get the maximum SAFE performance out of your engine.
The switch to 42's won't give you more power, if you're not upgrading anything else. Why do you feel the need to go bigger? How much boost are you making? 30 lb injectors are good up to around 450 hp, and if you need to upgrade you could go with 36's, 42's are huge.
thanks guys, i was thinking on #42 because i though that i was goin to get more power when i get the aluminum heads, my boost is 6 so far, so i think #42 is to much fuel for it, but with all my modifications so far, i feel my car like a stock 5.0, and i don't know why, i already took it to a performance shop, and they said that it wasn't necesary to get it tune at this time, so they just recommend me to get new cold ngk spark plugs, ford racing spark plug wires , mallory distribuitor and a adjustable fuel regulator, so i buy this stuffs, and now i feel the car with less power,

so i don't know what to do now, i think i goin to sell my car , i hate to do this, but am tired of deal with my car, thanks for all your advice.
1 - 4 of 4 Posts
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