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.

 

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.

 

okay so the exhaust smell is okay then?

And yes your first sentence was correct.

 

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.