Schyluer Jarman

Hey guys! New to the forum. Had a question about my 2009 Honda Civic Hybrid. So, I didn't know my car has TWO CATs. And my friend who normally hooks my family up with cheap parts and repair told me it's going to be 1100 dollars. Well I live in an area where we burn our trash and we don't test for emissions at our DMV... I read that other people in my situation with a Honda Civic (Non-Hybrid) just take off the CAT and put a straight pipe on it with a threaded hole for an oxygen sensor, and than they get better engine performance and gas mileage. Can I do this with a Hybrid? Is there a specific way I can do this? The car is worth like 3000 I don't want to pay a grande for two new CATS.

nsxmatt

Is it just throwing a code for the cat or is there a drop in performance from it being clogged? Most the time the secondary o2 will detect a inefficient cat and throw a code but the performance will be the same and you can just continue to drive it. The one cat is built onto the manifold and you cant just weld a piece of pipe there. Best option if you're not going to replace them is just gut them and drive it.

Schyluer Jarman

It had a code pop up. Don't remember which one.. And when i drive it it stutters, especially when the AC is on, don't know if that makes a difference or not. Thanks for the reply Matt. Oh, and if i gut my CATs would my engine performance and MPG go down or up? I'm getting mixed reviews and info on that.

nsxmatt

Well with the engine light on you may see reduced MPG but the car will actually breath easier so performance and economy would improve if the computer doesn't change anything.

holmesnmanny

Why even bother with this ? Just leave it the way it is if you don't want to spend money.

nsxmatt

An engine is a air pump. If the cat is melted to the point it's stopping the flow of the exhaust the car won't run.