"Gutting" your cat

[Art0ir]

Ever have someone point something out to you and wonder "why the hell didn't I think of that before now?"

We were discussing restrictions of an exhaust system on a TDI on another forum, and obviously how the catalytic converter is a major choke point, but removing it altogether can create problems for MOT visual inspections. Someone mentioned literally gutting it; taking a 1/2" steel rod and a hammer and beating all of the internals out of it, creating a nice free flowing piece of exhaust that looks like a perfectly normal cat from the outside.

Eureka!

I've never seen this mentioned here before, has anyone else done it? I'm really considering it now next time I get my car on some axle stands. The restriction of the exhaust was kind of rendering any sort of induction improvements useless in my opinion, but perhaps gutted cat + smoothed airbox + cold air feed would make a nice cheap combination of home made mods?

 

[cupradan]

without the internals it would fail the mot on the emissions test

 

[Art0ir]

without the internals it would fail the mot on the emissions test

Not on a diesel

And I've heard of plenty of petrol owners on here flying through with decats before provided the car is in good shape

The main advantage would be to get past the problem of the tester saying "No cat - fail"

 

[truCido]

a diesel doesn't need a cat for an MOT?

 

[Art0ir]

a diesel doesn't need a cat for an MOT?

By law, every car has to have a catalytic converter. That said, diesels don't get their emissions tested as they are so low anyway.

So all I need to guarantee a pass, is for the examiner to see a cat and tick his box.

 

[truCido]

Never heard of a diesel failing for having no cat....you sure its the law?

 

[LEE69]

Yes no cat needed for a diesel.

 

[Andrewcupra TDI]

no CAT needed ( or dogs )

mine passed no probs at all ,

and as said they dont check emissions only smoke testing ,

 

[DannyC87]

I have a gutted CAT on my LCR; and a none gutted one for the odd day of the year...

 

[Andrewcupra TDI]

lol , can always do what we done to my bros beemer , have the cat section removed and a quick swap area so that very odd day of the year was , undo clamp swap job done

 

[undefined]

sounds a good idea... all these cars running around illegally... tut tut...


wheres my bar and hammer

 

[undefined]

on 2nd thoughts.. i speaking to my mate who has a pd130 bora mapped up.. he took his cat off and he said his turbo was spooling up on idle.. anyone else experienced anything of this nature?

 

[Andrewcupra TDI]

before i fitted my carbonio induction kit , just a green panel filter

it spooled up very quick about 1200rpm ,

as for illegal , dont think mine is tbh , as said she passed the mot no probs at all

 

[Ashmeister_UK]

I dont think the RSPCA will be very happy if they find out you gutted your cat

 

[Andrewcupra TDI]

not sure if gutting is worse than stuffing

 

[s4oopie]

would you not be better pushing a piece of tube through the cat to reduce the affects of pulsing due to there now being a large space that gases will be forced into and forced out again .... wich is probably why the bora was spooling as it created a vacuum pulling on the turbo whilst on idle
that way its a de-cated pipe that has the cat surrounding it

gutted and stuffed cat all in one what will the rspca make of that then ?

 

[Mr_Dave]

on 2nd thoughts.. i speaking to my mate who has a pd130 bora mapped up.. he took his cat off and he said his turbo was spooling up on idle.. anyone else experienced anything of this nature?

My PD130 used to do that when it was sat idling pre-map or pre-decat