I'm redoin my exhaust, I'll probly run cats to just make it street leagal but I heard someone saying they don't run catalytic converters and I was just woundering how that works with the O2 sensors, is that just a permanent check engine light if you do that or what's the deal?

 

You can buy some o2 simulators or you have have somebody tune the o2 sensors out

 

Oh cool. O2 simulators sound bunk, can you have your pre cat 02 sensors for the job they are made to do and your post cat O2 sensors tuned out so there is no catalytic function confirmation requirement?

 

Yes, the rear o2's are only there to tell the computer that the cats are working.