42# injectors

[Boss 351]

Hi all, I need to get some bigger injectors for the added boost and to get rid of this FMU thing... Do I need 11-13 Ohms? I heard people having issues with brands other than FRPP? What specs do I need to ensure they will work and should I use EV6 adapters or properly weld on new connectors not requiring adapters?

This is for my engine (added a 95mm MAF, TweecerRT, new EFI wiring and 10-12psi of boost)

 

[VibrantRedGT]

FRPP injectors are made by Bosch I'm pretty sure and they make injectors for most major companies.

Depending on how much power your making (don't know your combo) here's the color to HP chart. The 42's max HP is 685BHP.

FRPP FUEL INJECTOR RATE by LBS. / HP RATING & COLOR

Injector Lb/Hr Max V8 HP supported by 1 injector Ford Color*
14 Lb/Hr 228 28.56 Gray
19 Lb/Hr 310 38.76 Orange
24 Lb/Hr 391 48.96 Lt Blue
30 Lb/Hr 490 61.19 Red
36 Lb/Hr 587 73.44 Dk Blue
42 Lb/Hr 685 85.68 Lt Green
60 Lb/Hr 800 100
*Colors are only constant for Ford Racing Performance Parts brand name injectors.​

 

[Boss 351]

hmmm seems like overkill now, I doubt it will be able to reach 500hp, maybe 450 at the flywheel (again that's speculation, won't know until it hits the dyno for the tune but 12psi of boost will raise the bar a little )... Sounds like 30 or 36 would be enough. I have a lean condition right now (at only 6psi) and don't want to play with the FMU. Rather have it setup so there's no need for such things.

So with overkill (42's) I'm guessing my idle will be rich and I'll make the car more of a pain to drive in the city? ACK! But everyone I speak to locally recommends to go big but there's no way in hell I'll ever reach 685hp with a Ford 302 block.

 

[Bullitt347]

42's will work fine on the street if the proper MAF is used and the fuel pressure is correct, proper fuel system and all. Engine will not run rich at idle at all. It is better to have it and not need it, than need it and not have it. According to the Ford Racing catalog, on a forced induction engine, a 39 lb/hr fuel injector is only good to 408 HP at 85% duty cycle and a 47 lb/hr injector is good to 492 HP at 85 % duty cycle. I would definitely think 42 lb/hr injectors are the way to go given your combo.

 

[Boss 351]

42's will work fine on the street if the proper MAF is used and the fuel pressure is correct, proper fuel system and all. Engine will not run rich at idle at all. It is better to have it and not need it, than need it and not have it. According to the Ford Racing catalog, on a forced induction engine, a 39 lb/hr fuel injector is only good to 408 HP at 85% duty cycle and a 47 lb/hr injector is good to 492 HP at 85 % duty cycle. I would definitely think 42 lb/hr injectors are the way to go given your combo.

Thanks I've been researching this (slow day) and you're 100% dead on. Thanks for the info. Yeah I picked up a MAF that's calibrated for the 42's and the car is going on the dyno for a proper tune. I'm going to try and find the green tops and get that.

 

[RacEoHolic330]

FWIW, My 42's were showing 98% DC at around 530ish rwhp.

 

[Boss 351]

So what brand now? FRPP's greentops are discontinued. Are Venom any good?