Can emisions be low enough for MOT without CAT ?
09 January 2002 | 12:51 PM
#1
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From: Edinburgh
Just put my '98 sti V in for MOT and it failed on emisions (CO output too high, everything else ok). They didn't say anything about it having no CAT so I reckon if I can get the emisions down a bit it will pass ok 
.
The CO was 0.8 when it should be under 0.3. Anyone else been in the same boat ? From my limited knowledge of Chemistry I'd have thought with enough air going in, the CO would drop ? Am I just running too rich ? Any help would be much appreciated.
Thanks
Dave
. The CO was 0.8 when it should be under 0.3. Anyone else been in the same boat ? From my limited knowledge of Chemistry I'd have thought with enough air going in, the CO would drop ? Am I just running too rich ? Any help would be much appreciated.
Thanks
Dave
09 January 2002 | 03:05 PM
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Interesting point, i've been worrying about the first MOT for my V5 Sti. I guess you don't need a cat, as its not a EU approved car, so if you get the emmissions down, i don't see why it should fail.
Good luck!
Russ
Good luck!
Russ
09 January 2002 | 04:36 PM
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I put my STi4 in for it's MOT thinking that it had a centre cat (I have a Scoobysport downpipe) and would pass OK.
Unfortunately the "centre cat" was in fact an empty box (as is sometimes the case on STi4s) and I got similar readings as Kart-man.
They wouldn't entertain the "non-european approvals" idea as they said the car would have been fitted with a cat for that year in Japan.
So I borrowed a regular catted centre section from some kind chap on this board and the car passed OK.
It's probably worth getting a second hand C/S just for MOTs if you run a full de-cat.
Neil.
Unfortunately the "centre cat" was in fact an empty box (as is sometimes the case on STi4s) and I got similar readings as Kart-man.
They wouldn't entertain the "non-european approvals" idea as they said the car would have been fitted with a cat for that year in Japan.
So I borrowed a regular catted centre section from some kind chap on this board and the car passed OK.
It's probably worth getting a second hand C/S just for MOTs if you run a full de-cat.
Neil.
10 January 2002 | 04:26 PM
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From: Edinburgh
Thanks for all your answers guys. I've got 3 options now which is great as I had none last week (or at least no cheap ones !)
1 - The AFR route (I see there's even instructions on how to build one on the board
)
2 - Someone's offered to sell me a OEM p1 exhaust system, which should fit I think !
3 - I called around some local garages, and one of them offered to fit an exhaust for the MOT, put it through, and then take it off again for me !! They import scoobys and always have some lieing around apparently ! A nice option except they'll charge me thier time which will add up over the years ! Nice service though.
Anyway, thanks for all the help
Dave
1 - The AFR route (I see there's even instructions on how to build one on the board
)2 - Someone's offered to sell me a OEM p1 exhaust system, which should fit I think !
3 - I called around some local garages, and one of them offered to fit an exhaust for the MOT, put it through, and then take it off again for me !! They import scoobys and always have some lieing around apparently ! A nice option except they'll charge me thier time which will add up over the years ! Nice service though.
Anyway, thanks for all the help
Dave
10 January 2002 | 04:54 PM
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From: London
Kart Man,
Sorry to spoil your ideas but the instructions on the board detail how to build an AFR (Air-Fuel ratio) gauge - this just measures your CO in the downpipe. This won't change anything so won't help you I'm afraid.
What you may be getting confused with is a fuel controller which can change the fueling - you could fit this just before you go into the MOT station and crank this down to really lean and then take it off as soon as you leave. I'm not sure I'd want to fiddle in this way but it is theoretically easy to do - you've got to fork out for a fuel controller though. I think Power Engineering do an air flow based one fairly cheaply.
It will fit but do you really want this on your car and the labour charge for fitting this is likely to be >= £100 
The other option is to go to Scoobysport and "hire" their twin cat mid section to go and get your MOT done (if you're anywhere near Basildon). Ask Pete how much he charges for this? Changing the mid section is a really quick and easy....
Matt
1 - The AFR route (I see there's even instructions on how to build one on the board )
What you may be getting confused with is a fuel controller which can change the fueling - you could fit this just before you go into the MOT station and crank this down to really lean and then take it off as soon as you leave. I'm not sure I'd want to fiddle in this way but it is theoretically easy to do - you've got to fork out for a fuel controller though. I think Power Engineering do an air flow based one fairly cheaply.
2 - Someone's offered to sell me a OEM p1 exhaust system, which should fit I think !
The other option is to go to Scoobysport and "hire" their twin cat mid section to go and get your MOT done (if you're anywhere near Basildon). Ask Pete how much he charges for this? Changing the mid section is a really quick and easy....
Matt
10 January 2002 | 05:09 PM
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Would adding octane booster to bring up to octane level have any effect?
Does the type of ECU affect CO levels, like would a UK ECU cause a different CO reading than a Japanese ECU mapped for 100RON? I'm sure the different mapping would cause different actions to the same readings from the lamdba sensor.
Johny
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11 January 2002 | 03:36 PM
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What if the cat is missing from behnid the turbo? Are these hard to replace for an MOT? Similar position to kart_man.Looking for the least painful way of getting it through!
Ideally I would like to stay away from swapping exhaust pieces - then again I may have no choice & it limits me because it's not the centre cat that's been replaced.
Johny
11 January 2002 | 03:50 PM
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jmca.
What I was saying in my first post was that I have replaced the "cat behind the turbo" already and hence my car was unwittingly catless when I took it for it's MOT.
Your car will pass on the centre section cat alone and this is very easy to change out; there being only 2 bolts at each end and a centre support rubber.
neil.
What I was saying in my first post was that I have replaced the "cat behind the turbo" already and hence my car was unwittingly catless when I took it for it's MOT.
Your car will pass on the centre section cat alone and this is very easy to change out; there being only 2 bolts at each end and a centre support rubber.
neil.
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