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...

 

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.

 

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 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.

 

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.

 

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.

 

OKAY so I should be safe at 6psi???

Im looking into ford SVO 42lb/hr injectors for when I swap the 350 back in.

 

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!