[VM0824]

everyone tells me that 42# injectors are enough to support 500+ hp. but when i do the math it never adds up.. what am i missing here.

8 injectors
500 hp @fly ~ 420 rwhp?
bsfc ~ .65 (apparently it costs more fuel with a turbo than a supercharger, but i dont understand this at all since i thought turbos were supposed to be more efficient than superchargers)
max duty cycle = .8

id need 51#'s according to most calculators(which dont even take into account the fact that fords dont use 3bar pressure) fixed for 39psi, id need 54# injectors.

yet the guy at on3 and everyone else keeps insisting 42's are perfect for my application but i wanna be able to make 4XX hp to the wheels.

[fogged306]

42's will be at more duty cycle than I would use with that bsfc and 500 at the crank. If you're doing a turbo you're going to be using a tuner or getting a tune right? If thats the case, go with some 60# EV6 injectors (skinny body) with the minitimer connectors (fox style). The EV6 are more accurate at lower pulsewidth than the fat body ones so at idle with no boost it'll be easier to tune. And the fact that you're getting a tune means you don't have to limit your injector size as much.

[VM0824]

well see the suggested bsfc changes with each site i look at. im not sure what to use. some say .65 for turbos. some say .55

i was under the impression that the fuel/power would go down compaired to n/a only because your taking wasted energy(exhaust pressure) to add power. soo in theory shouldnt that improve efficiency? or at least more than a supercharger which directly costs power (from a pulley)?

and about the ev6, ive read that they cause alot of excess wall wetting due to their spray pattern being optimized for 4 valve applications. dunno the extent of this, but either way i guess i wanna move on up to 60's or at least 47's

[fogged306]

Nah, there's plenty of fox guys with EV6 injectors on their car, including me. I run 60# EV6's on my N/A car. I don't really know a whole lot about forced induction fuel needs, but I do know that at WOT, you always want to be richer than an N/A car. I suspect it has to do with how much the intake charge is heated up as compared to N/A. In the software for the quarterhorse, it says .65 for boost so I wouldn't think you're going to stray from that too much.

[VM0824]

Ok sounds great thanks again

[fogged306]

No problem

[VM0824]

i picked up some ford racing ev6 47# boys. M-9593-LU47. with some adapters. the great thing is these injectors dont flow 47@43.5psi like most other advertise. they flow 47@39.1. which by my calculations mean i can support 500crankhp on my setup with stock 39.1 fuel pressure and keeping the duty cycle under .8!

the best part is i picked up the set of 8 for $200 new on ebay. the adapters for another 30 and already found a flow sheet to tune here.


btw, this has got to be one of the most complete fuel system requirement calculators out there. i strongly recommend after using a bunch of different calculator (one for pressure multiplier one for hp/injector potential..etc)