boost vs. fuel requirements

Paluka21 · 12-24-2001, 01:17 AM

well I can tell you right now that 24# injectors are going to be too small for that application and hp. He's not running aluminum heads so he won't gain quite as much hp as a modded motor will. However, its still 14psi on an iron headed car which will increase chances of detonation. Yeah he can run an FMU, but why band aid the car if he wants it to be reliable and not run high fuel pressure maxing out the injectors. I say do it right.
here is a breakdown of what seems to be the hp output you 'might' put out.
ok, 190hp to the tires stock, we assume, plus 14lbs of boost, which will at LEAST give you 175hp to the tires, maybe more after a good tune. So, now we're looking at 375rwhp x .15 for driveshaft loss is like 430fwhp which is NOT out of the question here w/ this setup. By NO means would I run 24# injectors, you would actually gain power by getting rid of an fmu and going to a larger injector. Sure he may have enough fuel pressure but you want the volume there too

24# injectors 100% duty cycle for a s/c'ed motor is 349hp (flywheel), 30# injectors is 436, and 36's is 523hp. As you can see, a 36# injector would benefit him best from this setup.
Heck, Im running 50# injectors w/o an fmu and was LEAN on the dyno, Larocca actually lifted at 4000rpm on the first pull. A/F ratio was around 14:1 !! This was with 50# injectors, 255 internal, ati external boost pump, 44psi fuel at idle, 7 degree base timing, kirban 1:1 regulator, and only 8-9lbs of boost. 50# injectors for 464rwhp and no fmu is what its at now and its a little rich, but its safe, thats where you want it!
if you have any doubts at all, call or email jimmy larocca, hes a great tuner and he's a pro. his # is 732-723-1111 , or visit his site at www.laroccas-performance.com. I would explain to him your gonna be running a 14# intercooler procharger that you are putting on a near stock motor, that you want pump gas, and be safe with, like an 11:1 a/f mixture on the dyno, cause on the street there is more of a load, and more margin for error. This is just my opinion, but I like things safe

Also, about that meter, you may want to think about going w/ a pro-m75 bullet, blow through, s/c'ed calibration. They work well w/ the ati prochargers, at least I havent had any probs w/ mine.
good luck, and as I said, I'd give jimmy a call at the shop, he'll get you squared away, he's a big procharger guy anyways.
Dan
95 rio red cobra #2021

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12-24-2001, 01:17 AM	#1
Paluka21 Registered Member Join Date: Oct 2000 Location: Maryland Posts: 71	well I can tell you right now that 24# injectors are going to be too small for that application and hp. He's not running aluminum heads so he won't gain quite as much hp as a modded motor will. However, its still 14psi on an iron headed car which will increase chances of detonation. Yeah he can run an FMU, but why band aid the car if he wants it to be reliable and not run high fuel pressure maxing out the injectors. I say do it right. here is a breakdown of what seems to be the hp output you 'might' put out. ok, 190hp to the tires stock, we assume, plus 14lbs of boost, which will at LEAST give you 175hp to the tires, maybe more after a good tune. So, now we're looking at 375rwhp x .15 for driveshaft loss is like 430fwhp which is NOT out of the question here w/ this setup. By NO means would I run 24# injectors, you would actually gain power by getting rid of an fmu and going to a larger injector. Sure he may have enough fuel pressure but you want the volume there too 24# injectors 100% duty cycle for a s/c'ed motor is 349hp (flywheel), 30# injectors is 436, and 36's is 523hp. As you can see, a 36# injector would benefit him best from this setup. Heck, Im running 50# injectors w/o an fmu and was LEAN on the dyno, Larocca actually lifted at 4000rpm on the first pull. A/F ratio was around 14:1 !! This was with 50# injectors, 255 internal, ati external boost pump, 44psi fuel at idle, 7 degree base timing, kirban 1:1 regulator, and only 8-9lbs of boost. 50# injectors for 464rwhp and no fmu is what its at now and its a little rich, but its safe, thats where you want it! if you have any doubts at all, call or email jimmy larocca, hes a great tuner and he's a pro. his # is 732-723-1111 , or visit his site at www.laroccas-performance.com. I would explain to him your gonna be running a 14# intercooler procharger that you are putting on a near stock motor, that you want pump gas, and be safe with, like an 11:1 a/f mixture on the dyno, cause on the street there is more of a load, and more margin for error. This is just my opinion, but I like things safe Also, about that meter, you may want to think about going w/ a pro-m75 bullet, blow through, s/c'ed calibration. They work well w/ the ati prochargers, at least I havent had any probs w/ mine. good luck, and as I said, I'd give jimmy a call at the shop, he'll get you squared away, he's a big procharger guy anyways. Dan 95 rio red cobra #2021