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Old 11-15-2006, 06:01 PM
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Injector Question

Hey guys, I got a 305 TPI with L98 heads that I'm going to be running 6lbs of boost on. It has the Ford SVO 24lb/hr injectors and a Holley AFPR. Will I be able to get by without an FMU at 6psi boost with ECM tuning?

Thanks

Last edited by MattODoom; 11-15-2006 at 06:18 PM.
Old 11-15-2006, 07:56 PM
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Originally Posted by MattODoom
Hey guys, I got a 305 TPI with L98 heads that I'm going to be running 6lbs of boost on. It has the Ford SVO 24lb/hr injectors and a Holley AFPR. Will I be able to get by without an FMU at 6psi boost with ECM tuning?

Thanks

With a little 6psi you could get away with the 19lb injectors with computer work....those 24# injectors covered my *** @ 43-44lbs fuel pressure to 15psi and it still ran a tad rich...
Old 11-16-2006, 12:14 AM
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The 24#/hr seem to just make it at 6 PSI with an adequate IC. They are fine with no IC and hot air.

I am amazed that 24#/hr at stock fuel pressure worked on a 305 at 15 PSI. In order for that to happen the intake air temp. had to be non-intercooled and in the 250* F range. That thing didn't detonate like crazy?

I put Ford 30#/hr in the stock 305ci TPI I am building with a giant IC.
Old 11-16-2006, 12:18 AM
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Assuming a .5 BSFC (which is still optimistic for a blower) you need a 24# injector to make 300hp and still not run over 80% duty cycle. If you run a 19# injector at 99% you could do the same thing, but you will probably not have a long lasting injector or it might just go static.
Old 11-16-2006, 12:26 AM
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Originally Posted by junkcltr
The 24#/hr seem to just make it at 6 PSI with an adequate IC. They are fine with no IC and hot air.

I am amazed that 24#/hr at stock fuel pressure worked on a 305 at 15 PSI. In order for that to happen the intake air temp. had to be non-intercooled and in the 250* F range. That thing didn't detonate like crazy?

I put Ford 30#/hr in the stock 305ci TPI I am building with a giant IC.
It was non intercooled, with methanol injection and no detonation....until I went over 20 psi. I answer so firmly because he owns my old kit. I know exactly what it will and won't do. trust me Ford Racing 24# injectors around 44 psi with a chip burnt for the 24#'s I ran rich all the time.
Old 11-16-2006, 12:36 AM
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meth. injection........that changes everything. He didn't post that part. Without the IC I do believe the 24#/hrs will work. They would fall short with a good IC. Another thing he didn't mention.
Old 11-16-2006, 12:42 AM
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Engine: 3xx ci tubo
Transmission: 4L60E & 4L80E
Originally Posted by zapo
Assuming a .5 BSFC (which is still optimistic for a blower) you need a 24# injector to make 300hp and still not run over 80% duty cycle. If you run a 19# injector at 99% you could do the same thing, but you will probably not have a long lasting injector or it might just go static.
It is better to do the calc not based on BSFC and use airflow and AFR. For doing the HP calc. and turbos I would use .57 to .62 BSFC. Some injectors spray odd patterns when going static. I think it is more of a code thing though because of the on/off time calc. If the code was changed then going static would produce spray patterns that are OK. I wouldn't worry about longevity of the injector going static.
Old 11-16-2006, 12:56 AM
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OKAY so I should be safe at 6psi???

Im looking into ford SVO 42lb/hr injectors for when I swap the 350 back in.
Old 11-16-2006, 01:01 AM
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Engine: 3xx ci tubo
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You should be OK with 6 PSI with the setup that was posted.

Take a look at www.racetronix.com when you decide to get the new 350ci injectors. The Ford 42s are getting more expensive and other brands are becoming a better buy now. The Fords used to be a good buy because they were cheaper than the rest.
Old 11-16-2006, 01:12 AM
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Originally Posted by junkcltr
You should be OK with 6 PSI with the setup that was posted.

Take a look at www.racetronix.com when you decide to get the new 350ci injectors. The Ford 42s are getting more expensive and other brands are becoming a better buy now. The Fords used to be a good buy because they were cheaper than the rest.
OK!

Last edited by MattODoom; 11-16-2006 at 10:38 AM.
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