How many ways to gut a CAT ?

[S2central.net]

So we all know there are 101 ways to skin a cat...

But what is the best way to gut the internals of a CATalytic converter ?

There is little rust on the CATs (presumably stainless factory items) so I presume its just a matter of cutting the top half off, removing the internals (wiv a hammer) and then welding it closed again.

I can legally decat the V6 and I'd like to do this on a shoestring if possible... should release a few more ponies as well.

[Rusty]

Get some pipe and borrow a welder, got to be better than having 2 chambers to mess up the flow.

[Fat Audi 80]

If you can "see" inside, I would try a cold chisel and a hammer. The honeycomb in my hold ones was practically falling out.

Dest had my old ones, he will tell you...

Cheers,

Steve.

[GazzaG60]

if its rattly then mash it out. if not try drilling into it. should break up.

maybe fill the drilled hole with water and freeze it. pretty easy at the moment may manage some freeze-thaw action.

or get a cutter the size of the internal diameter and cut it out and slide a tube in.

[s2avant]

Jason has just decatted the V8 when he serviced the gearbox. Well worth it. He used pipe to replace the cats.

The shoestring way would be as Steve says. Hammer and chisel. Even if you cant see all the way through you should be able to smash up the honeycomb from either end then tip it out.

Ben

[dest]

No need to open it up, just use a long thin old screwdriver or similar with a hammer!
All you need to do is literally break up the honeycomb into small enough bits to get it out.
Obviously it goes without saying to avoid breathing any of the dust/particles...

[benntenn67]

Hi , isn't a cat in full working order needed to pass the MOT test ?

[andy10v]

If you just hammer out the inside you end up with a big empty box, creates turbulence, not good for flow and sounds funny.

I would cut the flanges off, bolt them onto the exhaust, tack in a straight pipe, then remove and weld up, you then have bolt in de cat pipes with good flow.

If you want an stealth de cat i guess you could sleeve the cats.

No need for a cat pre 92, certain month can't remember which.

[Kieron20V]

Not if it was registered before July '92 it isnt.

[benntenn67]

Not if it was registered before July '92 it isnt.

but mine is Aug 95 - so i have to keep the cat and it has to work ?

[s2driveruk]

Paul, cats sell so i'll get them off, cleaned up and listed on the bay and then just get some proper decat pipes made up personally, would be cheap to do and you get the right thing on the car first time.

[S2central.net]

Hadn't thought of selling them right enough... but they heavy. Liking the big screwdriver idea for a cheap bodge, but then the turbulence could be an issue with empty CATs... suppose I should do it right and find a man that can weld in a couple of suitable straight pipes - is not like I am in a hurry as the engine build will take me eons.

[spink]

Presuming you havn't already had a look inside them there's a big possibility that the contents of the cats have already disintegrated and fallen out,seen this on 2x '93 V6 coupes lately.

[S2central.net]

Ain't looked yet Spink, but they sure aint rattling...

[martinjs]

I would avoid gutting them tbh, i did it to my 2.6 80Q, cut them open then welded them up and it sounded terrible, resonated really bad.