This injectior has me pulling me hair out. Do I need 28's 30's 36's 10000000000's.....I give up!!!!! Question is what injector is everyone running in the low 400 rwhp range. I seen one formula that tells me I should be running 36's everyone tells me 30's. I'm so confused now I could buy a Ford. Well maybe its not that bad.

Any how what are you running?
How do they work?
What is the duty cycle?

And if there are any formulas to figure out which injectors to run.

I've read a zillion posts on this but I would like input from people running certain injectors.

Thanks Rob

 

Dont buy a F ord....ouch that hurts.
From my readings, its the whole fwhp*.45 (for non FI) and then /8 (cyl #). When they say 30#, cuz the rating is standard rating for 43.5psi, and we run 58.01 to 61psi in our fuel system. So, that works out to 34 to 36#, depending on which Fuel Pressure you use, On a gauge mine is at 61 the entire RPM band, so it comes out to 36# i do believe. I dunno either, using the formula of hpx.45/cyl says I only need 24#, but autotap and LS1Palm scanner says my IDC is over 80% at only 5000rpm. WTF? I am going to use a set of accel 30# i picked free, so it has to be better than the 26 at over IDC %.

 

30lb svo's would be more then enough for your application. I bet the 28's would even work.

 

Depends on what you use for bsfc for normally aspirated I use .55 which kicks the injector sizing up big time. So thats 18% more injector than using .45.

You also don't want to run the injector past 80% duty cycle so thats another 20% less flow. Anything above 80% and you risk damaging the injector

So thats 40% difference right there. So thats why you have such widely different numbers.

BSFC can be determined from a dyno run and is related to the AFR you are running.

Also remember at high rpms you have less time so a bigger injector can more easily keep up.

Gary

 

If you want to figure it out, try this link. With my new dyno # I must be pushing 100% duty cycle. 30# are on order.

http://www.rceng.com/technical.htm

David