are 01+ 28lb injectors sufficient for H/C?
11-13-2008, 11:27 AM
#22
Here's a good formula for figuring out what size of injectors you should use. You want to figure out your brake specific fuel consumption. Some general guidelines for choosing a BSFC number:
Nitrous, turbo and supercharged engines: 0.60
N/A street engines: 0.50
N/A performance engines: 0.45
N/A race engines: 0.40
First: Determine your horsepower.
I mean flywheel horsepower. The way I figured mine out was I estimated my bhp (I used 525 bhp, 447 rwhp, figure about 15-18% loss to the wheels)
Second: Determine fuel requirements
The equation is Horsepower x bsfc ( I used .50 for my h/c/i setup)
525 x .50 = 262.5 lsb-hr of fuel required
Third: Determine minimum injector capacity
Divide fuel volume by number of injectors
262.5 / 8 = 32.8# injectors @100% duty cycle
Fourth: Determine injector size
Divide injector capacity by duty cycle you want to be around 80%
32.8 / .80 =
41 LBS INJECTORS
That's the way I did it, if anyone has any better ideas I'm all ears!
Nitrous, turbo and supercharged engines: 0.60
N/A street engines: 0.50
N/A performance engines: 0.45
N/A race engines: 0.40
First: Determine your horsepower.
I mean flywheel horsepower. The way I figured mine out was I estimated my bhp (I used 525 bhp, 447 rwhp, figure about 15-18% loss to the wheels)
Second: Determine fuel requirements
The equation is Horsepower x bsfc ( I used .50 for my h/c/i setup)
525 x .50 = 262.5 lsb-hr of fuel required
Third: Determine minimum injector capacity
Divide fuel volume by number of injectors
262.5 / 8 = 32.8# injectors @100% duty cycle
Fourth: Determine injector size
Divide injector capacity by duty cycle you want to be around 80%
32.8 / .80 =
41 LBS INJECTORS
That's the way I did it, if anyone has any better ideas I'm all ears!
11-13-2008, 11:31 AM
#23
Another thing you need to consider is the fuel pressure. I believe the average psi for injectors is 45psi for example the SVO ford injectors. The ls fuel system is on a 60psi system which means if you go with a 38lbs injector for a 45 psi fuel system it will be a higher lbs fuel injector on a 60 psi system. I could be wrong on this one so if someone else would help me back this up it would be appretiated.
11-13-2008, 12:06 PM
#25
on my dyno generally 430 rwhp i suggest an upgrade of injector with a 28.8 lb injector, then again i had a customer that was out of money with 99 TA 26 lb injectors and i managed to make 445 rwhp on them, but the duty cycle was 110% lol, not good ....
11-13-2008, 04:45 PM
#27
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I ran 98 injectors on a 470 rwhp setup for 3 years with no problems. Built 4-5 heads/cam setups this year in the 450+ range with stock injectors and no problems.
You do not need bigger injectors for a heads/cam swap unless it's a max effort 346 (Trick flows, FAST, huge cam, etc etc etc)
You do not need bigger injectors for a heads/cam swap unless it's a max effort 346 (Trick flows, FAST, huge cam, etc etc etc)
A guy I know has an 02-up Z06 with AFR 225's, Vindicator cam, ported FAST92, etc. and he's on stock injectors with no issues.
11-14-2008, 12:29 PM
#28
i am runnin ms4 in my z06...when i was cam only with fast 90 90 i put 436 403 on mustang dyno...we ran it with tha stock injectors @ 110% so i moved up to some 36lb injectors now runs about 85% max...
11-16-2008, 12:05 AM
#30
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I installed 30lb svos in my 99 with heads,cam and fast intake along with bolt ons and the car made right at 400 to the wheels with a stalled a4 and when it was being tuned i was told the injectors were close t obeing maxed out. The svo 30lb injectors are like a 36lb injector in the ls1 because of the higher fuel pressure. That should give you some idea.
11-18-2008, 12:36 PM
#31
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On my '02 H/C w/stock fuel system, the injectors were going 100% @ 6450 (just below peak, 400rwhp) and were at 85% at 5600. I just installed a racetronix pump and harness thinking a volume/pressure problem but haven't scanned it yet to see if that solved it. If not I'll stick bigger injectors in it.
