MOT & Emissions

[Rusty]

Had my ABY MOTd a few weeks ago and the emissions data got me thinking. It was tested as a non-cat car so limits were 3.5% CO and 1200ppm HC.

Values for this year were 191 HC, so pass fine but the CO was 0.73%. THe difference is that I now have a sports cat...

What are the limits for a cat car? If there's a problem that might show itself in the future at another MOT tester then I'd prefer to have a year to sort it than a week.

[shark_90]

So does that mean it can be tested without a cat?

[anton]

So does that mean it can be tested without a cat?

not legally no, gues your mot man is a keeperany car made from 92 onwards i think it is will be on the cat regs, and any car made before then that had one from the factory, but since no mot tester can every be bothered to find out your basically safe. a friend of a friend is an mot tester tho and he said if you have a decat pipe, a lot of mot station test systems atomatiaccly go onto the non-cat ststem assuming its a pre 92 so you'll pass unless the mot man has a sharp eye and notices the auto detect.

end of the day, i always thought sports cats were so expensive as they can do the job of the normal cat and flow more air...otherwise whats the point.....

Ant

[Rusty]

It is an A registration car

[anton]

A registered?.......yours is K or L isnt it? or am i missing something here?.....

Ant

[Rusty]

Private plate A_CSY

[anton]

haha they think its an 84 or whatever A is...thats classic!!! wonder what else you can get away with

Ant

[Rusty]

It's more the fact that I've paid for a sports cat to avoid MOT issues and it would seem that the CO is too high to pass a CAT test

[anton]

well i had a quick perouse of other websites and i think the 'norm' is for HC to be about 75ppm and CO to be around 0.3% for a cat closed loop car. since the car is in closed look for the MOT it seems that all your readings are high...and the cat aint gunna do anything about HCs so i'd guess your problem lies in the engine not the cat....your obviously running V rich....good for power, bad for MOT man....how old is your lambda??

PS. those values could easily be incorrect, its just what ive seen from ppl that have passed on other forums, the point is the rastio between the two seems right

Ant

[Rusty]

Lambda is new. MAF clean.

Will get it checked somewhere I trust.

[mcandmar]

Am i right in saying there is no published emissions specs for cars this age? I have to import my S2 and part of the vehicle registration form requires the CO2 emissions in g/km. I assume thats only applicable to car from the last 10 years?

Last test on my 7A gave 28ppm and 0.04% running without a cat. Didnt sound right to me but it passed so i kept my mouth shut...

[Rusty]

I think it depends how many of the 30s the pipe stays in the exhaust

[dubmeister]

What are the limits for a cat car? If there's a problem that might show itself in the future at another MOT tester then I'd prefer to have a year to sort it than a week.

Cat test limits:
CO<0.3%
HC<200 ppm
Lambda 99-1.03

Sports cats very very very rarely pass the cat test.............better off fitting a bypass then refitting the cat for the test (unless you can find a friendly tester like yours!!!!!!)

[Rusty]

Right, have to see what happens then, seems like it's a bit close, makes me wonder what I've paid the £200 for

[Rusty]

Have emailed the exhausrt place to see what they think...