im gonna be having my turbo thrown on shortly and i have the gm s/c on it currently but i know the 310cc injector are for sure not gonna cut my fueling needs but i was wondering what size i should throw in, my thoughts was that 440's would be good and was looking at the 550's cause i have hp tuners and could get it to work but would the 550's be out of their efficiency/duty as i know injectors are supposed to run in a certain range
thanks for your help
my 310's cut out after about 7psi..... i would say go 440cc and you would be more then fine... as your tuning with HP so you can work with the exra injector amount
The First Twin Charged jbody
blue car (R.I.P) - 240whp @7psi..
silver car - 305whp 315lbs.tq @15psi (91 Octane) or 420whp & 425lbs.TQ @20psi (94 octane+Alcohol Injection)
All dynos run on a Mustang dyno
would 550's be totally over kill?
gt28rs and probably 10-14psi
yea with HP tuners you could go as high as you want pretty much... not sure who well it would work with a set of 1000cc injectors in there but with HP tuners you can fix it all
The First Twin Charged jbody
blue car (R.I.P) - 240whp @7psi..
silver car - 305whp 315lbs.tq @15psi (91 Octane) or 420whp & 425lbs.TQ @20psi (94 octane+Alcohol Injection)
All dynos run on a Mustang dyno
i was asking cause i want dont want to have the duty cranked to make it work for one and have the duty been super low for the other if you know what i mean
get 550's, I have a set of 650cc RC injectors, they idle fine, my fuel milage on the highway is great, and I neve have to push them past 60% with all factory fuel pressures, according to RC I can run 450 HP with them :shrug, 550 would be perfect, but 440 are cheaper, hmmm
HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED
i can get the injectors super cheap even for 550's so im not too worried
but what can the 440's flow hp wise as im not sure i could validate using 550's
not too you shifted as you are a huge help to me but im not following how this works...
im estimating that i will put down 260hp we'll say but im not too sure still how to figure it out
if you could please explain im sorry but im more of a visual learner
Alright.... I'll try to explain it a bit better...
My FAQ wrote:
IFR = (HP * BSFC) / (# of Injectors * .8)
IFR is the Injector Flow Rate in lbs per hour
BSFC is the Brake Specific Fuel Consumption. A good number to use is .55 for NA, .65 for boosted engines.
# of Injectors are the number of equally sized injectors you will be using.
The .8 number is the maximum duty cycle of the injectors. You can't run injectors at 100% all the time, they will heat up and burn out. .8 is the highest duty cycle that you should use, which is why you don't want to use stock injectors.
So, my 225 BHP car, with a BSFC of .65, I will use this formula:
IFR = (225 * .65) / (4 * .8)
IFR = 46 lb/hr, multiply that by 10.55 to get CC's, 485cc
Now, those are some huge injectors for a 225 BHP car, yes. In fact they are too big. So why use that formula? Well we need a basis, that is how much fuel the engine should be using at the horsepower peak. The formula above assumes you are going to be running your fuel system at 45 PSI, which you won't be.
So, lets say we want to see if we can get away with some 36 lb/hr injectors. Lets say we are running 60 PSI at the HP Peak. You can use this formula to figure out what the fuel injector flows at a certain PSI:
F2 = (P2 * F1) / P1
F2 = Flow (in lbs/hr) at the new PSI
P2 = Desired fuel pressure
F1 = Fuel injector flow at the rated PSI (P1)
P1 = Rated fuel injector PSI
In our example:
F2 = (60 * 36) / 45
F2 = 48 lbs/hr
Taking the first equation:
IFR = (HP * BSFC) / (# of Injectors * .8)
If you are estimating, lets say 275hp for some added breathing room...
IFR = (275 * .65) / (4 * .8)
IFR = (178.75) / 3.2
IFR = 55.85lb/hr
Ok, so for 275hp, you need 55.85lb/hr of fuel, that doesn't mean you need 55.85lb/hr injectors, it just means you need that much fuel at your TQ peak. If you have more fuel pressure at your TQ peak, then the injectors can be smaller. Thats where the next equation comes in, lets say you are running 12psi, and your FPR adds fuel on a 1:1 basis, WOT pressure is 50psi, boost peak pressure is 62PSI, if you get 550cc (52.4lb/hr), then the effective size of the injectors is:
F2 = (62 * 52.4) / 43.5
F2 = 74.6lb/hr
So 550's would be way too big... lets try 440's (42lb/hr)
F2 = (62 * 42) / 43.5
F2 = 59.8lb/hr
Much closer, and even room for improvement.
So my recommendation, 440's.
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Buy stuff from CarCustoms Ebay! Won't be disappointed!
all that is on RC engineering scott..you can go and just plug in some numbers that they ask you and find out your injector size... but i still said 440cc will be fine since your going for all the same stuff as me ... unless Levi gets his hands on your car hahaha
The First Twin Charged jbody
blue car (R.I.P) - 240whp @7psi..
silver car - 305whp 315lbs.tq @15psi (91 Octane) or 420whp & 425lbs.TQ @20psi (94 octane+Alcohol Injection)
All dynos run on a Mustang dyno
I would say to leave room for future upgrades, and some room for injector error, (provided they are close to the same price) 550 cc would be awesome. Like I said before, I am using 650 and they work great, like stock only they can provide fuel under higher boost. You will not be disappointed if you get 550 for sure, but with the 440 you might, it is so easy to up boost on the dyno and clip an injector.
HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED
with scott (LAFNGAS) he wont be temped to just turn his boost up ahaha and if he does i dont want to be there as he will be pushing his stock bottom end enough... his bottom end couldnt take what 440cc injectors would max out at... well no stock 2.4L could... and if it does not for long
The First Twin Charged jbody
blue car (R.I.P) - 240whp @7psi..
silver car - 305whp 315lbs.tq @15psi (91 Octane) or 420whp & 425lbs.TQ @20psi (94 octane+Alcohol Injection)
All dynos run on a Mustang dyno
Josh F wrote:with scott (LAFNGAS) he wont be temped to just turn his boost up ahaha and if he does i dont want to be there as he will be pushing his stock bottom end enough... his bottom end couldnt take what 440cc injectors would max out at... well no stock 2.4L could... and if it does not for long
im not going for a dyno queen by no means, as josh was saying i will be just fine with the 440's cause ill blow my bottom end as its still stock before i outflow the injectors and once my car is tuned, im leaving it the hell alone and not upping the boost cause im gonna be pushing the stock internals far enough as it is
