fuel injector question
02-21-2007, 11:17 PM
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fuel injector question Hi, I have a set of 42lb injectors and i was curious if these injectors will be okay after i get a tune? The set i have is rated 370-380 rwhp. also once i get a tune will these dump alot of fuel that i don't need? I was hoping to get some lower rate fuel,but my friend had some extras
02-22-2007, 01:47 AM
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From what I hear they can be tuned down enough for most applications, and will still give you an optimal A/F ratio. I've only seen a few cases where 42lbers were too much for the application, but it depends on alot of factors including the elevation of where you're driving. But I doubt you'll have a problem.
02-22-2007, 07:29 AM
#3
Injs are..
Originally Posted by TA1972
Hi, I have a set of 42lb injectors and i was curious if these injectors will be okay after i get a tune? The set i have is rated 370-380 rwhp. also once i get a tune will these dump alot of fuel that i don't need? I was hoping to get some lower rate fuel,but my friend had some extras
Most are flowed at 3 bars, 43.5psi. Changing the flow pressure, the specific gravity of the flow fluid, etc, all affect the results of the tests.
42# injs are likely rated at 43.5psi. You don't give the specifics of your application, but assuming they are running at 58psi, they are now flowing 48.5PPH.
Here are some comparisons, using various FWHP's, a BSFC of .5, duty cycle of 85%:
500FWHP = 36.76PPH
550FWHP = 40.44PPH
600FWHP= 44PPH
650FWHP=47.8PPH
I think these numbers indicate the fallacy involved in using "RWHP" values.
Without the specifics on the application, it's difficult to determine the suitability of those injs...
The tune is going to determine, in most cases, how the injs behave. There are some designs/brands known for poor linear flow results, and large injs may not allow short pulsewidths to provide smooth idle, etc, etc.
A set that's matched to the application, goes a long way towards being
.IMO, comparisons of performance parts, using RWHP is an absolute waste of time... There are far too many variables, to make the effort worthwhile. Dealing in FWHP is the accurate method, something most enthusiasts do not have access to.
Bottom line:
Choose the injectors that fit your application. If you are headed towards 600FWHP, then these 42's may well be a good buy.. If not, ????
Back to
under my injector bench.