Like said it`s not the cat that became law it`s the emmission levels that changed. For vehicles registered on and after 1st Aug 1992 the levels fell from 3.5% CO to something much lower, this was enforced on
1st Jan 1993. And again as said it was almost impossible to pass the test without a cat so they became standard fitment as from then. The actual emmissions test became more thorough too and as the emmissions tightened further it also became impossible to pass the test without the engine being fuel injected hence one reason for the demise of Lada in this country as they still fitted carbs to the end. The emmissions test did not become retro so vehicles registered before Aug 92 and after Aug 95 come under 3.5% CO, before Aug 95 and after Aug 72 (I believe) must be 4.5% CO or below and pre 72 the test is visual. Withou checking I believe these figures to be correct but it wouldn`t be the first time I was wrong either.
>
>>
>>
>>> From: "Doug"
>>> Organization: BT Openworld
>>> Newsgroups:
>>>
alt.autos.alfa-romeo,uk.rec.cars.classic,uk.rec.cars.maintenance,uk.rec.cars.m
>> isc,uk.rec.cars.modifications
>>> Date: Fri, 2 Jan 2004 17:03:43 +0000 (UTC)
>>> Subject: Re: When Did Cat. Converters Become Law?
>>>
>>>
>>>> Can someone please tell me when catalytic converters became mandatory for
>>>> cars for use in the UK?
>>>
>>> They aren't mandatory for cars for use in the UK - mine doesn't have one. >>>
>>> Cars built from 1993 do need them fitted though - not sure the exact date
>>> but I suspect you'll find that on the DVLA website easily enough >>>
>>>
>>A lot of people get rid of them don't they? I would have thought that if it
>>was fitted it would be mandatory to keep it. But, unless I'm getting the
>>wrong end of the stick, some of the people on
formatting link
have put
>>straight-through pipes in place of their cats.
>
>AIUI there are two issues here:
>1) Can your car pass the relevant emissions test without a Cat? If so
>you can remove it with impunity.
>2) The emissions levels changed in 1992, making it virtually
>impossible to pass without a cat.
>
>Pre 1992 cars will almost certainly be able to pass the relevant test
>without a cat (my Giulietta for example. The engine comes from a cat
>equipped car). That being the case, the car can be removed as many >have done.
>
>Post 1992 cars will almost certainly fail the more stringent emissions
>test without a cat.
>
>HTH
>Dates might be wrong.