Spectrum24x

Guys, i've pulled my injectors to send off to get cleaned and flowed and rather then spending the money to get my secondaries cleaned i'm thinking i'd rather get 720s as secondaries but i wont have ems for a year or so. The car has FMIC, full 3'' exhaust and intake and a fcd i've heard of people running the 720's without any ems and they did just fine, what do you guys think?

i know its not ideal and i wont get full function out of them but will it run better, or at least just as well?

Black Knight RX7 FC3S

iTrader: (7)

its going to run pig rich when the secondaries open up. 550cc to 720cc is about a 25% increase in fuel.
You are going to have some kind of fuel controller to make sure its utilized to its best. Maybe a safc until you get your EMS setup.

j9fd3s

iTrader: (3)

its 25% more fuel, but he's also making approximately 25% more power too...

RotaryEvolution

iTrader: (30)

except the stock ECU isn't mapped for them so the "pig rich" statement stands true. it probably won't hurt anything aside from your wallet in extra gas money.

Evil Aviator

Your car will get worse MPG and accelerate slower past 3800rpm, possibly bog down some at the higher rpms, and maybe foul the spark plugs. I can't think of any other major problems off hand.

It's more like 21% more global fuel due to the difference in pressure ratings of the fuel injectors (720cc@43.5psi is about 665@37psi). Also, the EMS will compensate for some of the power increase due to MAP, so the engine will run rich with the wrong injectors.