killerpenguin21

so was searching and ofund that to found the max power rating of a set of injectors you multiply lbs/hr x your desired duty cycle the divide that by the Brake Specific Fuel Consumption, which is usually .50 for all motor. Then multiply by 4 injectors...

So...

stock gsr Injector size 22.8 x Duty Cycle 100% / .50 BSFC = 45hp per injector
45hp x 4 injectors = 180hp

now im guessing if i grab an adjustable fpr i can obviously get over this (180bhp sounds like crap anyway). i think im going to get a new fpr anyway since my stock ex is only running 28ish psi at idle which i believe is a little low.

so my question is, how much pressure can you throw at the stock injectors?

im doing this more as an experiment to see if i can hit 200whp on my ls/vtec build (12.3cr on pro1 cams) on stock injectors before i put my 310's in after break in.

this will be tuned on crome with a permanently installed wideband.

00Red_SiR

ITR's also run 240cc injectors stock but made 195 hp (rating) on stock fuel pressure, so that calculation doesn't tell the whole story about what's possible.

Dry nitrous systems raise the fuel pressure in the fuel rail substantially, I remember reading somwhere where it said the pressure can climb as high as 70psi or so. It's how they deliver the extra fuel when needed.

The problem you'll run into is that when you increase the fuel pressure, it will add more fuel right across the whole rpm range which causes driveability issues and running rich problems in the lower ranges. I suppose with tuning like hondata you might be able to reduce the duty cycle to correct for that... interesting experiment though

killerpenguin21

well im only planning on going 50-55 psi on the rail, and yeah i realize the calcs are a rough estimate but god to know none the less.

crome will allow me to adjust the duty cycle. there was a thread somewhere of someone dynoing and tuning on just a adjustable fpr and making good power but i cant find that thread anymore.

if i cant make 200 i cant do it...

any other input?

killerpenguin21

bump

UncleD

iTrader: (2)

My roomate recently had his motor tuned(B16b) with mild cams, Spoon header, Spoon exhaust and Comptech Ice box. His injectors were at 95% DC at 170whp(Dynojet). I've seen motors dyno'd to 200 whp on stock injectors, but is this safe?

killerpenguin21

what fuel pressure was he running?

this is an experiment, as soon as it looks unsafe wide band wise it will be sopped and the bigger injectors will go in.

onepoint6i

i wouldnt go past 60psi wot on stock injectors..