3.4V6 : Can you "de-cat" and still pass the MOT?

[chadr]

Happy New Year everyone!

The truck has been suffering from a rattly exhaust over the last couple of months. I have a full stainless "cat-back" system and that seems to be fine. It is the manifold to cat portion that seems to be the issue, especially around the part where the pipes from the 2 banks join. I also have a leak just before the cat - i.e. under where the driver's feet are.

This got me wondering whether removing the cat completely was a viable option.

Also what are the available options regarding repairing/replacing this (manifold to cat) portion of the exhaust in general?

As always, thanks in advance.

 

[Crispin]

maybe a daft question but is the cat still needed if you running on gas? could you take it for an MOT with an empty petrol tank?

 

[chadr]

Not sure Crispin. It passed the emissions test when it was MOT'd with flying colours in November. I'll have to dig out the emissions slip but I noticed that one of the outputs (CO2 or similar) that was supposed to be within a certain percentage was recorded as being 0%. .

If I didn't need the cat to pass the MOT, then I would like to look at getting rid of it completely.

 

[Ecky Thump]

If you take it in on LPG they are supposed to leave it on for the test, hence the zero percent figure.
I'd like to think that you could ditch the cat but don't know for certain

 

[silvercruiser]

I know off people taking the cat out and re welding the outer bit back together but im not sure if its entirely legal.


Joe

 

[chadr]

Just did some research and it seems that the cat IS required for petrol cars but not for diesels as they only have a smoke test currently for the MOT.