I looked under my car tonite and something had gotten caught on it and its now not actually connected to the cat. Isnt it just a temp sensor to turn the light on the dash on when its too cold?
Anyway. I had some time to kill so I unbloted the cat and took it out and went for a drive. MAN. talk about loud. I sounded really deep and throaty but way way too loud. I then got the cat and put a peice of pipe in it and hit it with the back of an axe to smash the filtery stuff in it out. its a bit like chalk but really hard but brittle. so basically it is just now hollow with no restriction. There was no difference in exhause sound and no noticible increase in power.
I say that, but I tested it after I went back to stock intake. Before, I remobed the bottom half of the intake and tapped the filter on to the top and got a great response at low to mid range and a really cool deep sound at wide open throttle.
Anyway, im probably just going on a bit now, but if someone could answer that question, thatd be great.
Thanks from New Zealand

 

I think the oxygen sensor behind your cat is only there to let the computer know the cat is functioning properly. I removed my cat and havent had any problems, not even a check engine warning (the sensor is still there). I dont know why you didnt hear an increase in exhaust sounds...mine became alot louder.

 

Well the rest of the exhaust is still stock. Maybe I had gotten used to the extra power the "modified intake" because I put the intake back togeather as stock then tested it. But no. Exhause noise may have just a tincy bit more noise, but thats it. WHat size is the exhause pipe anyway?

 

Well I replaced the cat with a straight pipe the same diameter as the rest of the stock exhaust. I guess that would be 2" or 2 1/4". Anyways, you've gotten rid of one ristriction, now get rid of the resonator, stock muffler, and get a y-pipe