Gutting the Cat

[surfingooner]

Been reading older threads about getting rid of the cat, or gutting the existing one, and an advantage of gutting is that it 'appears' to still be there. How hard a job is this ? Is the pipe on a 2003 TD5 sufficiently straight so that I can get straight instruments to it, ie drills and other long sharp objects or is it too bent and I will have to get cut out and a replacement piece of pipe welded in ?

From what I have read other say it is well worth it ?

[rangieman]

I cut mine off and welded some pipe in place [bigwhistle]
Or you could buy a pre Eu3 down pipe and simply replace it[wink11]

[Lemo]

Chop it out and weld a pipe in!
I replaced the whole section with a terrafirma after market as needed a new flex coupling anyway.

[surfingooner]

I just spoke to an exhaust shop near me and they claim that to remove a catalytic converter is illegal ?

Really ?

[ScotchRocks]

Most developed countries have emissions laws requiring catalytic treatment of exhaust gasses to oxidise (add oxygen atoms to) carbon monoxide and uncombusted hydrocarbons. This is a good thing for urban air quality (particularly in high density population areas and areas prone to atmospheric inversion events) and greenhouse effect impacts (especially for uncombusted methane).

There is is possibly some argument for very high fuel combustion efficiency tuning of engines allowing a higher flow catalytic converter with less exhaust gas contact time, but that is a bit beyond my expertise.

Personally I would be be looking for performance improvements elsewhere and not gutting the catalytic converter... But your vehicle and your choice how to modify it.

[rangieman]

I just spoke to an exhaust shop near me and they claim that to remove a catalytic converter is illegal ?

Really ?
Yes it is illegal also removing your EGR is as well [bighmmm]
Laws are made to be broken but don`t get caught[bigwhistle]
Do you have a mate that is handy on the welder or like i said earlier just buy a down pipe of a model that did not have the cat early D2 is your friend[thumbsupbig]
And honestly whats a cat going to do on a Td5 for emissions any way[bigsmile1]

[Tins]

And honestly whats a cat going to do on a Td5 for emissions any way[bigsmile1]

Given that sulphur is the enemy of cats, and Aussie diesel was high in sulphur content until a few years ago ( About when the first HiPo diesels appeared in Audis and Beemers locally ),
I'd say "not much". Happy to be corrected on that though.

[Tins]

I just spoke to an exhaust shop near me and they claim that to remove a catalytic converter is illegal ?

Really ?

Any mod that interferes with emission controls that are mandated under ADRs is illegal. Lots of workshops fell foul of the EPI for removing devices that were fitted for ADR 27A compliance. Anyone who remembers the strangling effect of those mods back then (1986? ) would understand why people took the risk though.

Me, I'd get rid of it. The only way you'll get done is if you drive through an EPI test site, and, as rangieman says, I doubt they'd notice, as the cat is probably doing nothing.

[surfingooner]

Thanks Gents, since the EGR is long gone, in for a penny in for a pound I say. Yes I spoke to friend this afternoon, has a worshop as he re-builds pre-war cars for a job and he said he has welding gear and a spare exhaust I can cut up. Three questions if I may:

1) Cut the pipe, de-gut and leave the converter box on and re-weld, or just get rid of the whole converter - been reading that smooth pipe all the way is the best way ?

2) if cutting, do I still have to remove the cross-member ?

3) if I have to remove the cross-member, can I do a 10km round trip without it ?

I have a daughters basketball game in middle of afternoon so we have a 3 hour window to do the cutting and welding. As I have never welded before and he has offered to do it, should I remove the cross-member beforehand or will we have enough time to do everything in 3 hours ?

Please excuse my ignorance with this !!

Thanks again, Matt.

[Tins]

Thanks Gents, since the EGR is long gone, in for a penny in for a pound I say. Yes I spoke to friend this afternoon, has a worshop as he re-builds pre-war cars for a job and he said he has welding gear and a spare exhaust I can cut up. Three questions if I may:

1) Cut the pipe, de-gut and leave the converter box on and re-weld, or just get rid of the whole converter - been reading that smooth pipe all the way is the best way ?

2) if cutting, do I still have to remove the cross-member ?

3) if I have to remove the cross-member, can I do a 10km round trip without it ?

I have a daughters basketball game in middle of afternoon so we have a 3 hour window to do the cutting and welding. As I have never welded before and he has offered to do it, should I remove the cross-member beforehand or will we have enough time to do everything in 3 hours ?

Please excuse my ignorance with this !!

Thanks again, Matt.

Can't speak for the X member personally. As for the pipe, if you are going for the "in for the penny" line, I'd just cut it and do the straight pipe thing. My daughter has a XR8 that has loose baffle in the cat. The rattling drives her nuts. I'm old, and my ears no longer work so I don't care, but you may see ( hear ) it differently. If you are going to do it, do it, IMO.

[Tins]

Can't speak for the X member personally. As for the pipe, if you are going for the "in for the penny" line, I'd just cut it and do the straight pipe thing. My daughter has a XR8 that has loose baffle in the cat. The rattling drives her nuts. I'm old, and my ears no longer work so I don't care, but you may see ( hear ) it differently. If you are going to do it, do it, IMO.

That said, I reckon the flexible coupling should be saved. Not sure if that has been mentioned.

[rangieman]

I cut mine off on the car no need to to remove xmember[wink11]
Then i tacked a new pipe in place , I then removed the down pipe and welded it all up refitted hey prestto[thumbsupbig]

[surfingooner]

Took both cross-members out dropped the exhaust and replaced the box with a piece of stainless steel, my friend being a professional restorer, he sand-blasted the whole unit and painted it all in black heat paint. Looked too good to put under the car by the time it was finished.

instant sound difference, and yes hearing the turbo is very pleasant on the ear. Unexpectedly has made more difference to the power than I thought it would, car is quicker, considerably so when first picking up, a little difference but makes a big difference if that makes sense (maybe the stage 2 re-map has influenced this).

only downside is that is is also noisier, with mid-muffler already removed, but that said, the whole noise is meatier, tuned, and you also get to hear that lovely turbo at work. A job certainly worth doing.

And then I woke up and realised this had all been a dream and none of this had happened. The cat is still there !!!!

Thank you all for the advice given, great forum.

[sierrafery]

Your dream vas more like a premonition IMO...cos that's what will happen if you get rid of the cat [thumbsupbig]