S3 8P Exhaust system


Registered User
Hi all,

Got my S3 a few weeks ago and looking to tweek a few bits and bobs,

I was under the car the other day giving it a check over and i noticed after the first cat and second lambda sensor theres a small box (which im presuming is a second cat) but its also got a bypass witch i find odd?

im getting a custom cat back made up and i was wondering if i can do away with this second cat? its after the lambda sensor so wouldn't cause any running issues but im not sure how much it would effect the emissions?

Any help much appreciated :)



Registered User
Why not just replace the whole exhaust?
You're gonna need it sooner or later:p

If you want to repair the old one just buy new cats and go to the local garage and get it done!