How Much Boost Will Stock Injecters Handle

[khunjeng]

260kw on stock injectors with all other supporting mods using slide hi-flow running 17 psi. Also the use of a nismo fuel pressure reg helped.

IMO all the supporting mods for that output would include injectors. The duty would be close if not 100% at high RPM i.e. it its static.

Its is not recommended to exceed 80% duty cycle. Otherwise you will run the risk of the injector not being able to open and close quickly enough, which causes the injector to float half open. This may lean the mixture out, which is not going to healthy for an engine at high revs and under full load which is where this occurs. Under static conditions the injector cannot control fuel delivery anymore and based on this my assumption is why ppl see good results from installing an FPRs to simply add more fuel under this circumstance. IMO this would be the caveman approach.

There is an arguement that it only happens at high RPM and that doesnt happen all the time. As mentioned before the AFRs would be a good guide to see if this is happening.

IMO if ur spending the money on everything else just buy some 550cc NISMO ones and be done with it for an app under 280 rwkw

[Marco-R34GTT]

550c NISMO injectors, would they manage at 300kw?

Also, when replacing the injectors, how long after until you consider changing the fuel rail and fuel pump?

Any need for a rising rate regulator....

[Adriano]

Yep. 550cc nismo's are fine for 300rwkw no need for FPR

[khunjeng]

550c NISMO injectors, would they manage at 300kw?

Also, when replacing the injectors, how long after until you consider changing the fuel rail and fuel pump?

Any need for a rising rate regulator....

I doubt u will get to 300 without a new pump.

[ossie_21]

I have a gt30r, 20psi, stock injectors, just short of 400rwhp.

[MZTRBO]

also running 235rwkw on stock injectors and stock pump, no reg.

Ive also heard of people running big power (300rwkw) with stock injecctors..and I heard this from an exerienced tuner? But from what these forums say its impossible to run this/or dangerous to do so...it might be I dont know?

Im assuming that it may depend on the tuner and how he tunes it...People say rb25 AFM need to be upgraded over 220rwkw..mines fine at 235rwkw.

Its also good to consult with a tuner as they are the ones tuning these things on a daily basis and some for a long time.

my 2c

[MZTRBO]

I used nulon injector cleaner just before the tune as I run around alot with the empty fuel light on which usually picks up all the sludge from the bottom of the tank..

[MZTRBO]

ossie 21 what pump are you using?

[32vspecII]

my rb25 afm was runing out of resolution on about 200rwkw , stock turbo at 13-14 psi , if it was a cold night (i assume because of air density

[MZTRBO]

I wish i knew the explanation of different parts maxing out at different power. I know that no 2 parts are the same, though I have a good feeling is has sumthing to do with the tune.

Cheers

[32vspecII]

it has lots to do with the dyno IMO

it probably has most to do with that . the only other factor thats variable here is AFR , a lean mixture will make more power with less air and rich mixture will require more air to make the same power . i would expect most people who have a tune though will know what to look for in their AFRs so most tuners would be roughly the same as they are aiming for good AFR curve , so not enough to produce great variences . there will also be some variance in the calibration of each individual AFM , they may vary voltage slightly for a certain amount of measured air due to age or tolerance

but to get 30-40 rwkw difference i would say it would be mostly dyno variations with a bit of the above . i know my figures were on a notoriously conservative dyno