Does my mini need a catalytic converter to pass its MOT?

This is an age old question that I spent some considerable time looking into in the summer of 2006, and as such the original articles and links to the VOSA website are no longer valid.

Most MOT websites simply state that if your car was first used after July 1992 you have to take the BET (Basic Emissions Test), which is too tough for a non-cat car to pass. And from 2002 the emissions regs changed and got even more complicated.

However, having been told by two separate mini specialists that my 1994 mini should be okay without the cat for the MOT, thusly opening up options as far as off the shelf stage one kits are concerned I decided some more research was required.

Unfortunately there are a few gaps so don't take this as gospel, and consult with your MOT tester before changing your exhaust system, because after all, even if your car is exempt if he fails you all you can do is appeal, and I suspect that takes a very long time, leaving you without your pride and joy on the road.

Cars from 1st August 2002

Have a cat test with vehicle specific limits, unless an exact match isn't found on the database and then the limits are:

At Fast Idle
CO2 <= 0.2%
HC <= 200ppm
Lambda 0.97 - 1.03

At Idle
CO2 <= 0.3%

This of course doesn't really effect us, so what about minis??

Cars first used between August 1995 and July 2002

If there is an exact match in the emissions database a cat test is done to those specified limits and if not.

At Fast Idle
CO2 <= 0.3%
HC <= 200ppm
Lambda 0.97 - 1.03

At Idle
CO2 <= 0.5%

Cars first used between August 92 and July 95

If there is an exact match in the emissions database a cat test is performed within those limits, and if not a non-cat test is used. As per cars from prior to August 1992 but with a tougher requirement on C02, as follows:

CO2 <= 3.5%
HC <= 1200ppm

Cars first used before 1st August 1992 don't need a cat to pass the test.

Cars first used between 1st August 1975 and 31st July 1992

For the bulk of mini production cars need to meet the following criteria

CO2 <= 4.0%
HC <= 1200ppm

Cars first used before 31st July 1975

A visual test only is required, back until somewhere in the 1930's I believe, at which point no test is used at all.

Emissions Database

You will need your chassis number to use this information

The engine code is the 8th letter of the chassis number, and the serial number is the last 6 digits

1.3i Auto TBi Engine Code X Serial No 059845 onwards CO2 at Idle 0.75% CO2 at Fast Idle 0.3% HC 200 ppm Lambda 0.95 - 1.09 Min Oil temp 70 ºC

1.3i Manual TBi Engine Code X Serial No 059822 onwards CO2 at Idle 0.75% CO2 at Fast Idle 0.3% HC 200 ppm Lambda 0.95 - 1.09 Min Oil temp 70 ºC

1.3i TBi Engine Code Y Serial No 060488 onwards CO2 at Idle 0.75% CO2 at Fast Idle 0.3% HC 200 ppm Lambda 0.95 - 1.09 Min Oil temp 70 ºC

1.3l MPi Engine Code Z CO2 at Idle 0.5% CO2 at Fast Idle 0.3% HC 200 ppm Lambda 0.95 - 1.09 Min Oil temp 70 ºC

My old mini 35 had the engine code 'D', so as you can see it didn't have a match on the database and as such a non-cat test was required

It would appear that even Spi's up to a certain point don't need the cat, and that carb'd mini's never do. And it's only the MPi's that definitely do.

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