De-cat S2

[Joss Walker]

Has anyone removed the cat and replaced it with a straight through pipe? Promax do a kit for this with claims of extra bhp - not something I think is too realistic on my 21 yr old 111k engine but does it affect the sound at all? I'm assuming that a cat (especially an old one) acts a bit like a silencer - what do you guys think?

 

[PSH]

Hi Joss

can't speak for the S2 but in general removing a cat from the car will release some extra BHP. Sound may be a bit throatier as well but can't say for sure, I'm sure someone here with an S2 must have already done this and can advise better. One thing though, iirc a car of your year needs a cat for it's MOT, I think this came into effect from your year onwards but can't say for certain.

Pete

 

[nick9one1]

I did mine myself.

Bought a meter of straight 3" pipe for about £12, chopped the old cat out and welded it in place.

I cant 'feel' any difference, but dont have any figures to back that up.

Sound is slightly throatier, hardly anything though. Certainly nothing like changing your backbox to a 'sporty' one.

 

[graham.webb]

Good idea to speak to Promax....I intend to do this (but only when the back box gives up), but they advised that de cat with the Janspeed back box is a bit louder.

 

[eddieedmo]

on my 1991 S2 it had the origional non-cat mid box and I initially put a Dansk back box on and sounded good and then put a straight pipe section on instead of the origional non cat mid section and it is too loud and rasps at 4000rpm going back to origional non cat mid box when get chance.

Nick []

 

[Neil Haughey]

Mine is 89 dB with a plain SS pipe in place of the cat and Dansk rear section. I had Maniflo in Salisbury make it for me on a while-u-wait basis about a decade ago.

 

[GlennS]

ORIGINAL: PSH

One thing though, iirc a car of your year needs a cat for it's MOT, I think this came into effect from your year onwards but can't say for certain.

Pete

Catalytic converters are required on [spark ignition] vehicles registered after 1st August 1992.

 

[Diver944]

Hi Joss, I missed your post whilst away. My S2 has a straight pipe instead of the cat, cost was £100 from a local exhaust place in Northampton. I can't say I notice any performance gain but I had to do it as my cat was holed. Noise is slighty louder but not uncomfortably so, send me a message if you are ever near Northampton and you can have a listen

 

[zcacogp]

ORIGINAL: GlennS

ORIGINAL: PSH

One thing though, iirc a car of your year needs a cat for it's MOT, I think this came into effect from your year onwards but can't say for certain.

Pete

Catalytic converters are required on [spark ignition] vehicles registered after 1st August 1992.

I don't think this is the case. Isn't it that they tightened the emissions requirements on that date to the point that a non-cat car is likely to struggle to pass the test, but the rules don't specifically require a cat to be fitted?


Oli.

 

[chrisjcoe]

Catalytic converters are required on [spark ignition] vehicles registered after 1st August 1992.

I like this thread! My main car (Volvo S40 2.0 TD) has a cat/filter on it, horrible thing and wish I could remove it before I have to throw away £1k to get it changed. The chrome tip/cover on my 1989 944 is shot so needs changing, I'm going to check to see if it has a cat and might rip the entire thing out if it has, or rather add it to my list of jobs to do!

 

[Joss Walker]

ORIGINAL: Diver944

Hi Joss, I missed your post whilst away. My S2 has a straight pipe instead of the cat, cost was £100 from a local exhaust place in Northampton. I can't say I notice any performance gain but I had to do it as my cat was holed. Noise is slighty louder but not uncomfortably so, send me a message if you are ever near Northampton and you can have a listen

Thanks for the offer Paul - but I've gone ahead and taken the plunge, makes quite a difference to the noise on my car but that may be because it is only ever driven with the roof down so I will hear a lot more than in a coupé. I love it though! I don't feel any power difference but I have had so many engine based changes recently I wouldn't really be able to tell what caused what. I must admit that I didn't realise so many members have done this, its probably why I though so many cars sounded so throaty at the Rutland meet this year

 

[Diver944]

ORIGINAL: Joss Walker

I didn't realise so many members have done this, its probably why I though so many cars sounded so throaty at the Rutland meet this year

Blummin boy racers []

Welcome to the gang

 

[GlennS]

ORIGINAL: chrisjcoe

Catalytic converters are required on [spark ignition] vehicles registered after 1st August 1992.

I like this thread! My main car (Volvo S40 2.0 TD) has a cat/filter on it, horrible thing and wish I could remove it before I have to throw away £1k to get it changed. The chrome tip/cover on my 1989 944 is shot so needs changing, I'm going to check to see if it has a cat and might rip the entire thing out if it has, or rather add it to my list of jobs to do!

There is currently no requirement for a UK TD to have a catalytic converter and no emissions test. There is only a particulates test. My Golf TDi has been de-catted for years and always swans through its MOTs.

 

[GlennS]

The definitive list of what is tested and against what standard is given here

http://www.dft.gov.uk/vosa/repository/Emissions%2017th%20Edition.pdf