Pretty sure my catalytic converter is done. Which one not sure yet till I take apart the exhaust and do a visual. My question is do I need all 3 cats to pass a smog do you think I can get away with just replacing the main cat (one with the pipe for air pump) or do I have to replace all 3? quoted over $800 for all 3 cheap NAPA cats.

Or is there a recommendation for a cheaper replacement?

my ultimate plan is just to have the cat for smog tests only then put a cat delete pipe in.

1990 RX7 13B NA

 

You can get away with punching out the pre-cats, leaving the shells in place, and use just a main.

 

Excellent, Thank you!