Anyone know the impact of not running a 02 sensor on a 12a carb 1984 car
 

Does anyone know exactly what running without a 02 sensor attached does to the fuel mixture? I have a stock 1984 12a with stock carb and stock exhaust. I knocked the 02 sensor off the exhaust (maybe it just got fragile at 24 years old) and before I replace it I actually wondered exactly what the impact would be to leave it off. The car appears to run fine. Any thoughts?

So far as I know it doesnt do anything. Just like your carb has a TPS, and that doesnt really do anything that I know of. It think its just for all the emmissions sensors and stuff. But in real world performance, it shouldn't make a lick of difference.

The 12a being carburated does not have an o2 sensor. It does however have a pyrometer, (exhaust gas temp sensor). As I understand the pyrometer only signals a waring light if your exhaust temp gets to high. So no worries you should be fine without the pyrometer.

The exhaust temp switch on a the RX-7 (all generations) is just a switch mounted to the floor near the cats/thermal reactor. It's nothing more then a temperature switch used to illuminate a warning light if there is a fire under the car.

As far as I know there are no O2 sensors on any 1st gens save the GSL-SE. Are you sure it was an O2 sensor?