Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: bp_porcaro on 11 September 2010, 11:38:14

Title: Removing CAT on 2.5TD
Post by: bp_porcaro on 11 September 2010, 11:38:14
Few questions for the knowing members with experience on a 2.5TD ......

1. Is it possible to de-cat a 2000 facelist 2.5TD GLS
2. If yes, how is it easiest to do.
3. What are the advantages or disadvantages to running without the cat
4. Are there any issues on the engine management with sensors etc
5. Does removing the cat affect the running of the Turbo
6. Will it still pass the MOT

Any thoughts appreciated...Cheers, BP
Title: Re: Removing CAT on 2.5TD
Post by: hoofing it on 11 September 2010, 18:20:46
You can de-cat the td as there is no lambda sensor fitted.
It realy all depends on who mot's it some can be fussy.
I haven't done mine yet but am planing to once i can get a hold of a down pipe.
I plan to cut off the flange leaving enough to attach a flexi to fill the gap.
as for performance it should be alot better and won't effect the engine in any way :y
Title: Re: Removing CAT on 2.5TD
Post by: tidla on 11 September 2010, 18:27:11
mot wise should not be an issue as test levels are still quite high.
as the cat does some of the exhaust damping, i should imagine some noise increase.

in the gallery section at the mo is a pre lift mig with such a mod..

http://www.omegaowners.com/forum/YaBB.pl?num=1284220865
Title: Re: Removing CAT on 2.5TD
Post by: hoofing it on 11 September 2010, 18:30:18
Quote
mot wise should not be an issue as test levels are still quite high.
as the cat does some of the exhaust damping, i should imagine some noise increase.

in the gallery section at the mo is a pre lift mig with such a mod..

http://www.omegaowners.com/forum/YaBB.pl?num=1284220865
so it will sound better then ;D ;D ;D
Title: Re: Removing CAT on 2.5TD
Post by: bp_porcaro on 11 September 2010, 19:14:04
Has anyone tried, or is it possible, to take off the cat section of exhaust and try knocking out the inside of the CAT material (ie flexi ram rod, and bashing the outer case) until as much comes out as possible and then re-fitting ??
I believe the CAT inner material is quite fragile, so this might bepossible.
Title: Re: Removing CAT on 2.5TD
Post by: Shackeng on 11 September 2010, 19:18:07
Quote
mot wise should not be an issue as test levels are still quite high.
as the cat does some of the exhaust damping, i should imagine some noise increase.

in the gallery section at the mo is a pre lift mig with such a mod..

http://www.omegaowners.com/forum/YaBB.pl?num=1284220865

This thread sounds interesting to me, but what does the above mean?
Title: Re: Removing CAT on 2.5TD
Post by: tidla on 11 September 2010, 20:10:47
smoke density check on diesels has not been reduced a great deal since introduction.

current levels are:
2.5m for normally aspirated.
3.0m for turbo.

the old smiley face transits can still meet this requirement without too much drama.

Title: Re: Removing CAT on 2.5TD
Post by: Kneepad on 11 September 2010, 20:43:20

I believe I read in an earlier thread that Elite_ Pete was planning to decat his diesel. Would be nice to hear his views.


 :y
Title: Re: Removing CAT on 2.5TD
Post by: tidla on 11 September 2010, 20:47:49
Quote
Has anyone tried, or is it possible, to take off the cat section of exhaust and try knocking out the inside of the CAT material (ie flexi ram rod, and bashing the outer case) until as much comes out as possible and then re-fitting ??
I believe the CAT inner material is quite fragile, so this might bepossible.
you can do but.. the void isnt ideal for gas flow.

straight pipe welded inside maybe.

other motors, decat pipes are available off the shelf.

Title: Re: Removing CAT on 2.5TD
Post by: Shackeng on 11 September 2010, 22:37:50
Quote
smoke density check on diesels has not been reduced a great deal since introduction.

current levels are:
2.5m for normally aspirated.
3.0m for turbo.

the old smiley face transits can still meet this requirement without too much drama.



Thanks :y :y :y
Title: Re: Removing CAT on 2.5TD
Post by: bp_porcaro on 12 September 2010, 00:38:25
other motors, decat pipes are available off the shelf

tapper888

do you know which section for which model fits directly on (do you know a part no???)
Title: Re: Removing CAT on 2.5TD
Post by: Kneepad on 12 September 2010, 00:54:31
I think Tapper888 meant they were available of the shelf for other motors but would not fit not yours.   ::)
Title: Re: Removing CAT on 2.5TD
Post by: Kneepad on 12 September 2010, 01:07:48

One possibility is to pop in to your local Quick Fit Fitter and see if they will make up a pipe section with flanges that will go on in place of the cat.

One time I had a hole in a section of pipe in an old van they didn't have that section in stock so they made it up while I waited. An hour later job done. 
                                                           :y
Title: Re: Removing CAT on 2.5TD
Post by: Shackeng on 12 September 2010, 09:07:04
Is it legal to remove the CAT?
Title: Re: Removing CAT on 2.5TD
Post by: Kneepad on 12 September 2010, 15:28:21
Quote
Is it legal to remove the CAT?

I would imagine so, as long as the car meets the emmission requirements without it. Many car owners do it.   :y
Title: Re: Removing CAT on 2.5TD
Post by: VXL V6 on 13 September 2010, 00:23:31
Quote
Quote
Is it legal to remove the CAT?

I would imagine so, as long as the car meets the emmission requirements without it. Many car owners do it.   :y

It's just a smog test on a diesel.
 :y
Title: Re: Removing CAT on 2.5TD
Post by: Omegatoy on 13 September 2010, 07:57:41
Quote
Quote
Quote
Is it legal to remove the CAT?

I would imagine so, as long as the car meets the emmission requirements without it. Many car owners do it.   :y

It's just a smog test on a diesel.
 :y

true!!! also its not a cat as we know it from petrol burners, its a very very basic cat, its more of a burner than a cat :y
Title: Re: Removing CAT on 2.5TD
Post by: hoofing it on 14 September 2010, 08:11:46
Quote
Has anyone tried, or is it possible, to take off the cat section of exhaust and try knocking out the inside of the CAT material (ie flexi ram rod, and bashing the outer case) until as much comes out as possible and then re-fitting ??
I believe the CAT inner material is quite fragile, so this might bepossible.
DON'T ever do this to a cat this is highly toxic and dangerous it's not just platinum and gold thats used its what the core is made off is a asbestos like material :o
Title: Re: Removing CAT on 2.5TD
Post by: aaronjb on 14 September 2010, 09:49:57
Quote
DON'T ever do this to a cat this is highly toxic and dangerous it's not just platinum and gold thats used its what the core is made off is a asbestos like material :o

Ceramic, last time I checked, which turns into a very very fine dust which, you're right, can easily cause the same symptoms as asbestos (silicosis) if you breath it in over a reasonable period..

Having said that I've done precisely that plenty of times on MR2 Roadsters (they have preCATs right next to the exhaust ports that have a habit of breaking up 'naturally' and getting sucked back into the engine via the EGR system, nicely mullering the bores) and so far I haven't died (yet) ;) Just be sensible and don't take great lungfuls of the stuff in, do it in a well ventilated area and, if you have one handy, wear a mask (at least a paper gauze type).