Hello,

So I've been busy putting an upgrades list together and stuff to get done on my Z.
Internet searches have only gave me an article from Engine Labs & Automotive Forums (Broke_a_****).
Both articles explain that bigger injectors tend to be less reliable when metering fuel in lower RPMs, however Im not clear that
duty cycle was taken in account.

How much can the duty cycle be reduced on Z32 injectors (side feed Jecs, NISMO, TOMEI, etc) before there are problems?
I'm on the fence as far as deciding to get 615 or 740 injectors; could I get 740s and reduce the duty cycle to say 60% or 55%?
Im trying to avoid having to buy 2 sets of injectors.

What is consistent with the articles above and other articles, is that everyone has the 80%-85% max duty cycle for
injectors, top or side feed, as the safe zone.

Regards.

Are you worried about idle issues? Many many many folks have 740 Nismos, including my self, and no issues at idle. I’m on my 6th year with them on a SZ tune.

Idle issues & knocking would definitely be a concern, but no.

My worry would be to have injectors too big or too small, then having to come up
with more money for another set; I have a AEM Series 1 PnP, if it helps.

How much HP are you running? What duty cycle you have yours on?

I'm at 390 WHP and 402 TQ, following upgrades: stock turbo,3"-2.5" exhaust, z1 intercooler ,740 inj. Sz dyno tuned, 94/93 oct fuel, selin dual intake, EBC max boost 16.9psi.

Another local z32 has same mods with the addition of full 2.5" intake pipe and 2.5" intercooler yielded 430 whp and 420tq.

@itsa300zx: It seems to me that a Z below 500hp with 740cc inj has a low duty cycle on the inj
by looking at the numbers you posted. Thanks BTW.

1. Size the injectors to your needs.
2. Nismo injectors of all varieties are proven to run well in all applications down to almost stock HP levels
3. Size the injectors to your needs, if you plan on running any 5xx series turbo (JWT or Z1) then the 615s should be plenty unless you're looking at E85 or Nitrous.
4. Size the injectors to your needs.