Stan Weiss
Member
yes, they are the ford racing green top injectors. so i guess that means that the 39psi that i see at wot is correct?
NO!
If you have a 42 lbs/hr injector that is rated @ 39 psi and at WOT you have 10 psi boost with 39 psi fuel pressure you have a 29 psi pressure differential and your injectors are flowing a max of 36.22 lbs/hr. The question becomes how much fuel does your engine need?
I calculate that a 4.6l at 6000 RPM with 10 psi boost needs a mass air flow of around 3460 lbs/hr. With an AF of 12.5:1 each injector need to flow 34.6 lbs/hr
(3460 / 12.5 ) / 8 = 34.6
Is the "NO" in my post easier to read now?
Code:
A/F lbs/hr needed
10.5000 41.19
10.6000 40.802
10.7000 40.421
10.8000 40.046
10.9000 39.679
11.0000 39.318
11.1000 38.964
11.2000 38.616
11.3000 38.274
11.4000 37.939
11.5000 37.609
11.6000 37.284
11.7000 36.966
11.8000 36.653
11.9000 36.345
12.0000 36.042
12.1000 35.744
12.2000 35.451
12.3000 35.163
12.4000 34.879
Let me clarify that the injector lbs/hr is what is needed for that air fuel ratio. Based on what duty cycle you want as your max you than need to calculate injector size. If I want a 11.0:1 AF @ 90% duty cycle 2 WOT then 39.318 / .9 = 43.6867. You would need a 44 lbs/hr injector