I recently saw a site where a guy had gutted his cats. His approach was to take an electric drill and mash up the insides then remove them.

I was wondering if anyone had tried the same or if anyone knew of a reason not to (other than the fact its devious, underhand and will spoil warranties etc).

 

Your car will also fail a roadside emissions test/MOT if you gut the cats ?

 

Well yes but surely thats the same as fitting a de-catted aftermarket exhaust system.

I was wondering whether there would be any downsides..presumably an aftermarket system just has a straight 3" pipe..would a cat box (albeit empty) be bad ?

 

The decatted aftermarket exhausts mean you have the cats to put back when MOT time comes round, if you get caught at the roadside and there is obviously no cat you could theoretically get done more than if you have the box still on the car, you could just say it must be knackered. I dont know if they actually look into the cats when they do a roadside test. The only thing to watch is you would have to get all the internals out of the box, or you would end up with a very low performance car