gutted my CAT and loved the sound and the lil bit of gains on the MPG. I didn't get the CEL to come on either. I talked to by buddy at the muffler shop and he said not all trucks will throw the CEL at you when the CAT gets gutted.

 

Usually the only time the OBD will pitch a code with the cat removed is when you are putting strain on the motor. Towing, romping... etc. I've got like 40K miles on my truck with out a cat now, and have only pitched a CEL one time for not having a converter on there. I was climbing up a hill with about 1000 pounds in the bed of the truck.

 

you have to get all of the catalyst material out. and if you have straight pipes behind it then it'll sound like a stock car. if you have some sort of muffler then it'll have a nice growl.
now if you knocked it all loose and didn't get all of the chunks out then put it back together then that loose piece(s) can plug up the muffler.

laramie, i thought you got a fastman o2 sim. am i wrong?

 

^ Yea, you're wrong. I've got a Bosche O2 sensor in the front and a stocker in the back. That's it. Stock housing, nothing in there. Y's off into two Flowmaster 40's series.

 

laramie, what do you think happened with hammer_down's truck? i'm thinking that some of the catalyst got lodged further down the exhaust. that or maybe the front o2 got knocked around.

 

Unless his truck is a CA setup, that's about the only thing I can think of, unless he knocked the tip off the O2 sensor or something. Maybe check the wires on it, and just flat get a new one.

 

thats the reason i said to remove the o2 sensors before beating up the cat.