Daz_WRX

Im after some bigger injectors for my P1, i beleive there 440cc at the moment, what injectors fit? and what size shall i go to. Mods include, decat, full system, induction kit, front mount and remap.

Thank you

p1mark

i assumed your mapper has told you that the 440's are running at a high duty cycle?

you match your injectors to the rest of the spec and expected BHP - 440's will be good for round about 340 BHP, next step up is 550's which will see you to 400 BHP.

Daz_WRX

Hi mate, yeah i have an apexi unit. The duty is around 90-93% duty. i have a walbro pump but im running standard pressure. Im having it mapped again when the front mounts fitted, could i get more out of the injectors if i upped the fuel pressure or will this just cause more problems...

Thanks mate

p1mark

Yes you can, obviously assuming you have an adjustable reg of course.

If the only change you have made is the FMIC your existing injectors should cope.

Just remind your mapper it was running 93% before, he will dial in a bit more pressure if he thinks its required.

If you are planning any more mods in the future though, i would put 550's in now to give a bit more headroom.

Daz_WRX

Cool, just the basic mods really, ie porting the standard headers, wrapping the exhaust, etc etc nothing too substantial yet. I will purchase an aftermarket fuel pressure regulator. Im not very clued up on injectors and duty etc, but if i were to increase the pressure, will this lower the duty cycle or will this have no difference at all? I assume raising the pressure will allow more fuel in?

Thanks Mark

p1mark

yep, increasing the pressure a tad will lower the duty cycle percentage a bit i.e your injectors will not need to work as hard to deliver the same fuel.

P1/STi 5/6 will be fine on 440's at just the basic decat/induction kit stage.

Out of curiosity, who is mapping it? and i assume you know about www.p1woc.co.uk

Daz_WRX

Yep I am a member on P1woc. The mapper is Simon aka Jolly green monster.

p1mark

You should speak to JGM to confirm (as he knows your car already)

Daz_WRX

will do mate. Well thanks for the advice chap, Greatly appreciated