Mitchocalypse

iTrader: (2)

Hey there, I know that with RX-7s, you need to be careful monitoring your AFR. I'm considering buying one but it seems to be running quite rich. What exactly does this entail? The car is a 93 so its got TTs and I'm not sure if it's important but it's got a Greddy cat delete exhaust.

i just thought the cat delete thing might have something to do with it because you'd be left with more unburned fuel.

RotaryRocket88

iTrader: (7)

So you're calling it "rich" because you smell the exhaust?

AFR refers to the air/fuel ratio inside the combustion chambers; it just happens to be that wideband 02 sensors calculate this value from the percentage of 02 present in exhaust gases. Removing a catalytic converter does not change the mixture inside the combustion chambers, but it will increase the amount of HC/CO/NOx that exits the tailpipe.

Mitchocalypse

iTrader: (2)

okay so the exhaust smell is okay then?

And yes your first sentence was correct.

gracer7-rx7

iTrader: (16)

Depends what you mean by "okay". Do you enjoy smelling nasty exhaust fumes? If so, I guess its okay.

Without the main cat, you will never pass emissions.

Without some kind of cat or exhaust restriction, you may find it difficult to control boost - especially when it gets cooler. The stock fuel system only supports enough fuel for 10-11 PSI of boost. Be careful or you'll blow your motor.

Spend some time reading the 3rd gen FAQ thread for past threads on the topic.