I havent been on these forums for long but I keep hearing about people decatting their exhausts to get more power. Obviously a cat is there to reduce emissions so my question is a) do people decat and hope they wont get tested (i.e. roadside emissions test) and b) if you did get caught whats the likely punishment?

 

i got the centercat removed, and hope to get the downpipe one removed soon, ill then get long life zausts to make me a sports centre cat, so i keep the best of both worlds,

But i am worried about an emmish test

 

im a mot tester so can tell u the car must have a cat for the test.
as for road side test's im not sure but there might be a fine.

 

I think a roadside failure was £60 fine but I suspect they are after the old smokers rather than newer models so you would be a bit unlucky to get pulled over. DL

 

there's also a query over insurance which we have mentioned before the bit in the policy about vehicle being roadworthy. That said, I have started a thread on this before and responses seemed to be that provided you tell your insurers it shouldnt be a problem.

Speaking to my dealer about this an effect on warranty at the weekend. They said they hadnt ever had a claim blocked by IM due to a decat. They also said that some cars will still pass the MOT although there was no certain way of telling when or which cars - I presume this is down to testing conditions?

 

I was wondering about this too. However I have noticed that at one of the country's biggest Subaru dealers, who see a lot of Impreza Turbo's etc they are actually advertising their own 'performance upgrade' that involves removing the Cat and also stating in their own sales documents that this upgrade has been done - although the de-catting is not mentioned specifically. I was quite surprised at just how much extra power this gives - from a 'normal' turbo, you will get around 270ish BHP and one of the service managers was saying that it improves sound too :-)

 

Will you post the number for such miracle workers!

 

oops

[Edited by bug-eyed wonder - 1/14/2002 9:41:14 PM]

 

I posted the DETR rules on this a while back. Basically, it is not a legal requirement to have cats fitted in the UK. HOWEVER, the car must be capable of passing an emissions test - either roadside or MOT - and most, if not all cars will not pass without a cat - so catch 22.


Sharkspeed
If a standard turbo gives 270bhp with just a decat, i'll eat the cats lying in my garage....

Varies from car to car/rollers to rollers, but probably in the region of 230-245bhp.

 

A few weeks back I calculated the average bhp for unmodded MY99/00 on the dyno's page - it was 235bhp IIRC.

A full decat should, I'm told, give 20-25bhp - so 260bhp is not unreasonable.

This is born out by the dyno readings for most de-catted cars being around 250-260bhp (though most have a air filter change as well).

So may be dealer is not exaggerating that much!?

Cheers
Tim

PS Dave - I'd really like to get hold of the DETR regs, I can't find it on the web, can you post a URL if you've got it?

[Edited by NBW - 1/14/2002 10:26:38 PM]

[Edited by NBW - 1/14/2002 10:27:20 PM]

 

A friend of mine chanced her arm and avoided a roadside test by saying that she had only just set off and it wouldn't be a fair test. They let her carry on her way.

 

I've only heard that same certain dealer that I think sharkspeed is referring to claiming 270bhp for ppp cars with decat which is slightly more realistic.

 

Any rough ideas about what the new uk-Sti could produce with 2 of the standard 3 cats removed, just wondering as I'm having it done before delivery...

 

I think I'll be lucky to see a genuine 260bhp from a decat PPP with boost controller running 2 PSI over the whole range more than PPP. Basically apart from the 2500-5000RPM range my wastegate is virtually shut so I don't think you can get much more out of a TD04L at the peak power point except for maybe changing the manifold as well. If you put on a monster exhaust (or induction kit) you might lose low down torque and gain some top end, but I don't think you will make a quicker overall car given that my ignition advance and fuelling are looking pretty good. This is on a rolling road that rates standard cars about standard (Star) but we will see - similar figures to Powerstation. Some people have 280+ for simliar setup car at PE. Depends on what you believe I suppose.

[Edited by john banks - 1/15/2002 10:30:06 AM]

 

Just learnt a painful lesson on this one. Am having to buy a new cat for my car ( 97 Ibiza Cupra ) as it wont pass the mot without it. Works out about £300. Wouldnt mind but the people who are now saying this has to be done are the same ones who sold me and fitted the cat pipe last year! they never gave me the old cat either! feeling a bit on the angry side at the moment. argghhhhh!

 

I got dumped by my old insurance company when I told them I decatted the car (95 WRX) as they said it was not legal! I have since got insured by another company who know all about the decatting (thanks Rum ). It has since been recommended to me to tell insurance companies that you have a full stainless steel exhaust and not comment on the cats unless asked. This is sort of holding info back from the insurance company but could cause problems in the even of a claim. I personally prefer to declare anything that they could use against you!

When I last got the car MOTed I got told that because it was newer than 1994 it needed one by law regardless of whether it passed the emissions without or not. I also thought that UK cars after Aug 92 had to have one by law aswell as my previous car was a 93 Rover200 Gti which I decatted!

I stand to be corrected.

 

D T-S is correct - all cars post '94 must be capable of passing an emissions test at any time, not just at the MOT time.

I sufferred the indignity of failing a roadside test (randon DOT one with Police pulling cars of a main road) in my 2 week old VW a couple of years ago. I was initially threatened with 3 points or a £1000 fine, but changed it to a produce a valid emissions check certificate. Apparantly they could have impounded the car if they wished, but given my story about it being new (etc etc), I got away with it.

Duncan

PS. I was extremely unlucky to get pulled - I do no know anyone else who has come across one of these roadside tests.

 

Finally found the info on the DETR site here:

http://www.roads.dtlr.gov.uk/consult/emissions2001/03.htm

Basically says £60 fixed penalty for failing the roadside test - but presumably you could also be charged for a seperate offence under consturction and use regs if you've modified the vehicle by removing the cats?

Tim

[Edited by NBW - 1/16/2002 7:50:36 PM]

 

More good stuff:

http://www.roads.dtlr.gov.uk/consult/emissions2001/03.htm#chapter5

There is an option to have the roadside test deferred:

'5.5.1. The Road Traffic (Vehicle Emissions) (Fixed Penalty) (England) Regulations 2001 allow drivers who have been stopped under these Regulations to request a deferred test. THIS OPTION IS OPEN TO ALL DRIVERS STOPPED but one likely to be exercised only by those drivers sincerely concerned that the test may cause damage to their vehicle.'

You then have 21 days to produce a valid MOT, which must be dated no later than 14 days after the date you were stopped.

How much does an MOT cost these days?

Cheers
Tim

 

rotdot,
What's the deal with regards to jap imports? I have a MY94 WRX Wagon (jap import) and it's fully decatted. I'm told it should pass the emmisions tests though.