550cc good enough?

Do you have a inter-cooler? Are you on the stock T25 or T3 ?

Depends on your horsepower capabilities of your setup.... Fuel Injector clinic puts you maxing around 440 crank HP assuming stock fuel pressure.

https://fuelinjectorclinic.com/hp-calculator

my suggestion… get a good tune first, then check your actual duty cycle (if possible).

im running 550CC Grams with vac/reference, they are around 60% duty cycle @ 400 WHP @ 17PSI on a hx35.

with goals i'd suggest at least 750 or 1000CC for head room and to keep duty cycle low. If you are not targeting over 400WHP 550CC is fine.

Now if I can't run a 420WHP setup on 550cc, I'd love for people to send me some links for bigger injectors, please and thank you!

Injectors are less complicated than they appear

Replacing the original connector plugs is highly recommended as the original plastic plugs break down and crack.

Upgrade to the PastPowerPerformance O-ring rails, find a set of R32 skyline injectors, splice in ev-14 connectors, new gaskets… then do yourself a safety solid and convert your fittings to AN so you don't die in a fire.

before attempting start-up perform multiple leak checks.

550CC should safely get you over 400WHP, until duty cycle approaches 80% you're safe - this also relevant to you or your tuners comprehension

Also remember if convert to E85 you need larger injectors compared to gasoline power goals.

Do you idle smooth with the large injectors ?.. just asking … . ( jwt 420cc on my t4/t3 turbo no problem ) but what about other larger injectors … ? do they pulse out small amounts at idle ? and then there's what cam is installed …

Smooth idle is largely determined by your setup and tuning.

If you are competent with K values and idle/warm up trim you should be quite as a honda 4banger at idle

im running E85 on 1200cc injector on nistune. Running a little rich 10-12.1 afr but holds a good idle at 900 rpm. I think 1200cc is already past the limit a little of E85 for decent idle. I had no problems with idle and afr with my previous 450cc dsm blue tops.