norbak1258

hey guys, I have a quick question. Can the stock injector be put to work at 85% duty cycle? if so how? I have been asking this question and it is still unclear to me. Some people say that you can, some peple say you cant.
This is the reason I ask. This is from rx7.com

"Your next limitation in the fuel system comes from the injectors themselves. The stock Turbo II fuel system uses two 550cc injectors for primaries and two 550cc injectors for secondaries which come on a higher RPMs (Non-Turbos use 460cc). Those injectors, maxed to their extreme limit (100%), will support approximately 420HP(*) at stock fuel pressures. You don't want to push the injectors beyond 80%-85% duty cycle though for reliability reasons.

If this is true I dont see a reason to buy 720 secondaries for mild upgrades like exhaust, filter and 12psi

Thanks guys for you time.

norbak1258

no one????

DaleClark

iTrader: (55)

I think I answered a similar question on the TeamFC3S forum...

Anyhow, the stock ECU seems to underdrive the primaries. Increasing the airflow meter signal with a Super-AFC or the like doesn't work - I don't know why, but it doesn't add more fuel. That's why people put in 720's and tune them down - tuning down works, tuning up doesn't.

BUT, the Greddy E-manage with the injector harness lets you directly add pulsewidth to the injectors in a 16x16 map. I'd love to see someone try it with a stock turbo/exhaust/etc - fine-tune the pulsewidth to stay in a good AF range. I'm running the E-manage on my car, but it's way past stock turbo .

Dale