removing cat S2

[ZenithalRavage]

Anyone here have experience removing the cat of the S2? My main concern is if you can just remove it (I take it the second cat and replace with straight pipe) without screwing up your motor management as there's also the O2 sensor between the cats if I'm not mistaken.....
Any info greatly appreciated, my cat is rattling and I want it out! [img]images/graemlins/thumb.gif[/img]

[Doug_RS2]

I don't think there is an issue with removing the cats on an S2 - you should have 2 of them. If you are getting replacement pipes made, get them made with brackets to support the exhaust otherwise most of the weight of the exhaust will be hanging from the turbo. The Lambda probe(only one) is just behind the turbo - you can see it from the engine bay - there isn't one after the cats.

I have no cats and as long as your S2 can pass the mot cat tests there is no legal requirement to have them fitted - you might need to argue this point with some testers that can't read the regulations properly!

[PhilT]

I have no cats and as long as your S2 can pass the mot cat tests there is no legal requirement to have them fitted - you might need to argue this point with some testers that can't read the regulations properly!

Really. I thought the deal was that you have to have the cats fitted for the MOT as they specifically check Carbon Monoxide levels with the cats on. If you then remove the cats, the vehicle is no longer 'road worthy', as it would fail the emissions test....?

[Doug_RS2]

Really. I thought the deal was that you have to have the cats fitted for the MOT as they specifically check Carbon Monoxide levels with the cats on. If you then remove the cats, the vehicle is no longer 'road worthy', as it would fail the emissions test....?

It's only after 1997(IIRC) that cars have to have CATS fitted to pass the MOT - Cars built later than 1993(IIRC) have to have them fitted when new but can be taken off as long as they pass the "CAT" test. The S2 should pass it without the cats fitted, if it is running correctly.

I will try and get a copy of of the official wording on this.

[Doug_RS2]

Quote from an MOT FAQ - by another S2 owner:


CAT test is an unfortunate term which leads many to think that the MOT is testing the Catalytic converter fitted to later vehicles but this is not so.

The MOT is testing emissions, so if the emissions from the tailpipe meet the requirements the vehicle passes. Whether a CAT is fitted is irrelevant. The deciding factor is the vehicles date of first registration. A "Cat" may be fitted to a vehicle which only needs to meet the two gas test and if the emissions are satisfactory, it passes. A "Cat" may have been removed and the vehicle is required to meet the "Cat" test standard by virtue of its first registration date. If the emissions meet the standard then it passes.

Many advanced design engines will meet the "Cat" requirements with a standard exhaust but of course may be emitting other pollutants not subject to the MOT.

Advanced emission tests must be carried out on fully warmed up engines, the oil temperature must be above 80 degrees C (some are set at 60 degrees C) and the idle speed must be within the manufacturers agreed tolerances. Both engine speed and oil temperature will be measured using equipment attached to the gas analyser.

During engine idle the engine must not be subject to electrical loading such as heated seats, heated rear windows and air conditioners. Electric cooling fans do not cause significant problems and can be active during the test.

Twin exhaust systems need to have the reading from each pipe tested and then averaged. A twin exhaust has two separate pipes from the engine manifold all the way back to the tailpipes. Systems with a balance tube between separate pipes are still considered a dual exhaust.

[ZenithalRavage]

Hey, many thanks for the info guys, now we're getting somewhere [img]images/graemlins/grin.gif[/img]
Ofcourse the rules here in the Netherlands are a bit different from those in the UK. Your "MOT" is about the same thing as our "APK" I reckon.
Anyway, I've done some searching and to pass our APK a car first registered before end 1992 (I'm in luck [img]images/graemlins/boots.gif[/img] ) doesn't have to have a cat and emission tests are more liberal.

Taking your info that removing the second cat doesn't effect readings to the ECU and my car was first registered before end 1992, I think I can be happy [img]images/graemlins/jump_clap.gif[/img]
I'll keep you all informed [img]images/graemlins/thumbs.gif[/img]

[ZenithalRavage]

Ok, haven't been here for a long while, but I said I'd keep you informed so if you want to check out my new exhaust pipe look here [img]images/graemlins/grin.gif[/img] (bottom of the page)