CAT removal in the frontpipe, CEL?
 

Hi guys,

If you remove the cat in the front-pipe, are you going to throw a code in these cars?

In my Miata there is a second downstream O2 sensor whose job is to basically verify that the CAT is there and working. The the upstream O2 sensor does all of the calculations for air/fuel etc. Therefore, if you remove the CAT, you get a code.

I live in MD so we have and OBD emissions check every 2 years, and I want to avoid codes. I want to get rid of the CAT if I can, I know high-flow is an option, but full removal would be preferred.

Has anyone confirmed whether you'll get a code or not yet?

I would assume it would throw a code. Most cars now days have 2 o2 sensors. One to read the exhaust fumes & determine how the motors running. The second to determine how much fumes r being left out as emissions

Removal of the front cat throws the efficiency code. Its quite annoying and when it happens you'll have idle issues not to mention power loss

Thanks for the heads up. I will stick to cat-backs.

Can't you get a CEL eliminator for this? That's what I did with my Elise when I removed the Cat.

Hmmm... There is no o2 sensor after the 2nd cat. You will get no CEL. One before the header cat and one after the header cat.