550 injectors Options

[lawngsx]

I am currently running an EVO III B16g and the stock 450s, uip, GM MAF-T, 3" exhaust, Walbro 255, etc. Well as you may have guessed, I have maxed out the 450s and am now looking for what to upgrade to. The options I'm looking at are 550s and 680s from either FIC or PTE. I'd like to stick with the same turbo for a while, even after a built motor goes in. Now the question is, will I max out the 550s with this turbo (running ~25psi)? I have a friend here at school that has a B16g, FMIC, etc and 550s and is convinced he has maxed them out at ~22psi.

Also, if I were to go with the 6xx injectors, would I need a burned chip to compensate for the idle or would I be able to iron things out with the MAF-T?

[natedogg]

With my 650's 80% duty cycle is about the most I've seen at 9K RPM at a boost pressure of 27 psi. If I start turning the boost up beyond that, the duty cycle does tend to get higher. I could probably use larger injectors in the future, but the 650's are about perfect for me now. Plus, like Eric said, I can always turn up my fuel pressure. I'm pretty sure the BR500 has more in it than 650's can take care of, if I truly want to max it out. I just don't think my poor stock bottom end engine can handle 35+ psi.

I think dsm-performance.com has some equations that will work out what the effective cc is for a given injector and fuel pressure. I used to have a duty-cycle map over RPM, that I worked out for my injectors. I'll have to see if I can dig that up.