Steve J.

How is a cat actually gutted? What's in there?

Nicole

Depends on the type of cat - ceramic versus metal. The metal is almost like a mesh, while the ceramic looks more like a piece of clay with tiny square openings on the front and back.

Go to http://auto.howstuffworks.com/catalytic-converter2.htm to see a picture of the ceramic type.

The higher flow metal cats are very popular in Germany these days, becasuse they provide the same sound and feel of a no-cat car, while making the 928's exhaust even cleaner. That puts the car into a better emissions class, and tax incentives pay for the conversion over time.

Barry Johnson

If you have the cat off of the car, its much easier. You can use a broomstick and slam it through it to break up the ceramic type, and maybe the mesh type. You just have to seperate the insides from it and 'gut' it out. Some (with ceramic type) have been able to just bang on the outside of the cats with a sledge hammer to break up the insides, and then fire up the engine and rev it to shoot it out the muffler, but I doubt that would work for us.

hacker-pschorr

First, for humane purposes, ensure that the cat is dead. If you find a cat allready dead, i.e., Road Kill Cat, so much the better. Next, obtain a board larger than the cat. Attach the cat to the board belly up, with the limbs tied out spread-eagle. Make an incision from the pubic symphysis up to the sternum and left to right under the rib cage. Retract the skin and muscle layers, exposing the peritoneal....









Oh C'mon, someone had to post it.

Rez

I'm waiting for that picture....

"Free Cat"

tresamore

A hammer, a long chisel w/o a round shaft and a crescent wrench. The chisel is hammered into the ceramic brick, the crescent wrench is attached to the chisel and used to turn it back and forth to break up the brick. Repeat this until it all comes out and then use the chisel and wrench to wrap up the stainless mesh around where the brick was. Keep winding the mesh onto the chisel until it pulls away from the inside of the cat and pull it out. Of course I've never done any of this.

Gretch

Your wish is my......

Rez

Well I asked for it.

Jim bailey - 928 International

Also note that a gutted cat becomes a resonance chamber and will at certain RPMs make an unpleasant rumble from under the car. The other option is to cut open the cat end to end remove the ceramic bricks honeycombs then tack weld in straight pipes from inlet to outlet before welding the cat back together. It then appears stock but actually is straight pipes.

Dave H.

you should also wear a dust mask and break it up in a bucket of water. the dust isn't too friendly to your lungs...

Garth S

This is a great approach, provided the welder is not a grade 'A' dufus; I installed a spare S4 cat on last week for a trial - which had the straight pipe treatment done in an earlier life. The trick of tack welding cheesy carbon steel exhaust pipe to the expensive Porsche stainless steel shell was obviously not mastered by the unknown welder.
The internal pipes are now loose, and at takeoff, rattle like a string of tin cans tied behind a Honeymooner's car leaving the reception.
There will be another welding surgery to remove these: Is the resonance unpleasant enough that fresh (stainless) pipes should be reinstalled - correctly? - or left empty?
Otherwise, I may have to rent my S4 out to honeymooners ....