hey guys everyone is talkin bout gutting their cats and stuff and i know this is prob a newb question but i want to know how you guys do it.. like i avent been underneath my truck but i think its welded on to the actual exhaust pipe

 

Cut the pipe behind the cat, remove your o2 sensor, take a long bar and ram it inside the cat. Bust up everything inside. Start the engine (with exhaust pulled to the side) Get the debris out with a couple good revs, then shut it down and make your you bashed it all out. Repeat until everything is gone. Then weld the exhaust back to the cat.

Most of the restricitions are on the inlet side of the cat. There are 2 small pipes bending sharply going into the cat. Add a ypipe and straighten the ppes going in as much as possible or even better have it going into a single 3" inlet and add a hi flow cat

 

The way I did it on my old S-10 was to disconnect the pipe between the cat and the muffler from the cat. The cat itself stayed connected to the y-pipe. Then I manuevered the " cat back" section out of the way, and got busy with a Craftsman pry bar set and a five pound hammer. This was in my driveway, on my back, with the truck on jackstands. This was the older brick type cat, I don't know what material they use now. Most of the pieces I was able to remove, the rest got blown out with the exhaust. Crude, but effective!

 

BTW, completely not legal.

 

Yeah but I wont tell if you dont!

 

I thought it was only illegal till you get caught lol. If you have to pass an Etest do not gut your cat,,,,,until right after the test [sm=devilangel.gif]

Gutting the cat could set off a CEL(check engine light)
The pcm could go into limp mode. If it does, try reseting the pcm by disconnecting the battery and turn the ignition on for 10 seconds. Reconnect the battery and the CEL should go away. If it doesnt you may have to get an o2 Simm from fastman.com or krcperformance.com. Tricks the pcm into seeing a reduced reading. Pair of resistors between the o2(rear one) and the pcm would probably work and save you $75.

1/4mile et reductions on average for my 96 5.9
.10 Edelbrock headers w/ypipe (only 14" K&N @ time)
.32 Magnaflow h/f cat 2in/1 out 3" exit
.18 Magnaflow h/f cat commits hari kari & gutted itself 2yrs later
.08 Magnaflow 3" glasspack all 3" to side exit infront of axle (Edelbrock/Flowmaster40 catbacks gave even less)

As you can see by how my 5.9 reacted, the cats were its at. Hi flow cats give a good boost in performance and will still pass an etest. Magnaflow, Catco and Carsounds are most popular.