Vantage Sports Catalysts and the MOT
Discussion
I know this one will have been done to death on PH but I just thought I'd post on my experiences getting a motorsport catted Vantage through the test for the last few years, might prove helpful to anyone struggling with passing an MOT, especially in cold weather. Bamford Rose fitted their headers and 200 cell motorsport cats to my 2011 car in Feb 2020. Since then, I have done three MOT, Feb 2021, Sept 2021 and now again in Sept 2022. The first and last emissions test results were interesting as there was one fundamental difference - temperature.
On a cold morning in Feb 2021, I dropped the car off at my local MOT centre after driving it 1 mile, and they tested it an hour later, effectively stone cold. On first attempt the CO levels exceeded the idle CO limit and it failed the test. I guess knowing what to do they ran it at fast idle for a few minutes, then did the fast idle test then the idle test immediately after.
It then just squeaked through on CO:
Fast Idle CO 0.2% (limit is 0.2%)
Fast Idle HC 17ppm (limit is 200 ppm)
Idle CO 0.18% (limit is 0.3%)
No need to mention lambda as the ECU will ensure this is OK. If you have a failure on this, there's likely a maintenance issue, inlet air leak or failing O2 sensor.
In 2021, BR MOT'd the car after replacing a failed body module and servicing it in Sept 2021. It passed but I got no copy of the results. I did note that the test centre was a good few miles from the workshop, so the car would have been decently warm for the test.
Last week, following the new anniversary, I took the car for what will be its last UK MOT, I also needed to understand if it could pass a French MOT (Control Technique - which uses the same emissions test and limits as UK) with the sports cats.
This time I booked an MOT slot in a known quiet period in the day, went out for a decent blast beforehand, promised the centre I would arrive at the precise booked time for the test to start, asked them if they could do the emissions bit first, if possible starting with the fast idle test. I also informed them honestly that the motorsport catalysts only really work when fully hot as they are designed for track use. I turned up with a fully hot car 5 min before the test and left the engine running, sniffing the exhaust to make sure that sweet smell of cold motorsport cats which takes so long to fully disappear was minimised (it never fully goes).
The result this time was an easy pass:
Fast Idle CO 0.04% (limit is 0.2%)
Fast Idle HC 16ppm (limit is 200 ppm)
Idle CO 0.01% (limit is 0.3%)
On a cold morning in Feb 2021, I dropped the car off at my local MOT centre after driving it 1 mile, and they tested it an hour later, effectively stone cold. On first attempt the CO levels exceeded the idle CO limit and it failed the test. I guess knowing what to do they ran it at fast idle for a few minutes, then did the fast idle test then the idle test immediately after.
It then just squeaked through on CO:
Fast Idle CO 0.2% (limit is 0.2%)
Fast Idle HC 17ppm (limit is 200 ppm)
Idle CO 0.18% (limit is 0.3%)
No need to mention lambda as the ECU will ensure this is OK. If you have a failure on this, there's likely a maintenance issue, inlet air leak or failing O2 sensor.
In 2021, BR MOT'd the car after replacing a failed body module and servicing it in Sept 2021. It passed but I got no copy of the results. I did note that the test centre was a good few miles from the workshop, so the car would have been decently warm for the test.
Last week, following the new anniversary, I took the car for what will be its last UK MOT, I also needed to understand if it could pass a French MOT (Control Technique - which uses the same emissions test and limits as UK) with the sports cats.
This time I booked an MOT slot in a known quiet period in the day, went out for a decent blast beforehand, promised the centre I would arrive at the precise booked time for the test to start, asked them if they could do the emissions bit first, if possible starting with the fast idle test. I also informed them honestly that the motorsport catalysts only really work when fully hot as they are designed for track use. I turned up with a fully hot car 5 min before the test and left the engine running, sniffing the exhaust to make sure that sweet smell of cold motorsport cats which takes so long to fully disappear was minimised (it never fully goes).
The result this time was an easy pass:
Fast Idle CO 0.04% (limit is 0.2%)
Fast Idle HC 16ppm (limit is 200 ppm)
Idle CO 0.01% (limit is 0.3%)
If the original MOT had been done properly, the temperature would have been seen to be below MOT limits and the engine would need running until that is achieved. The latest MOT has a requirement that the car is attached to the MOT testing equipment via the OBD socket and this would have kicked-out the original test due to under temp unless the tester overrides it.
8Tech said:
If the original MOT had been done properly, the temperature would have been seen to be below MOT limits and the engine would need running until that is achieved. The latest MOT has a requirement that the car is attached to the MOT testing equipment via the OBD socket and this would have kicked-out the original test due to under temp unless the tester overrides it.
to be fair, if they had done the MOT "properly" it would have failed! 
"Non original / missing catalyst & emissions equipment".
OP, I don't leave my 911 (with sports cats) unattended for the MOT & ensure the engine is well up to temp even though I'm less than 10 minutes from the garage who undertake it - I insist on the first slot on a Saturday morning so there's very little possibility of it failing the emissions part as they will hopefully not have any distractions. The garage know I'm fussy 
AdamV12V said:
to be fair, if they had done the MOT "properly" it would have failed!
"Non original / missing catalyst & emissions equipment".
True, buts that’s a slightly odd one for some Astons. Because some come with primary and secondary cats from the factory, but if you have the AMR pack fitted at the factory, the same car won’t have secondaries but will still be “original”. Whereas if you have the AMR pack fitted later the car will be the same as one with it factory fitted but now wont be “original”. "Non original / missing catalyst & emissions equipment".
BlackWidow13 said:
AdamV12V said:
to be fair, if they had done the MOT "properly" it would have failed!
"Non original / missing catalyst & emissions equipment".
True, buts that’s a slightly odd one for some Astons. Because some come with primary and secondary cats from the factory, but if you have the AMR pack fitted at the factory, the same car won’t have secondaries but will still be “original”. Whereas if you have the AMR pack fitted later the car will be the same as one with it factory fitted but now wont be “original”. "Non original / missing catalyst & emissions equipment".
To complicate matters even more the AMR V12S Performance Pack doesn't even always come with a cat delete! That depends on if you go for Pack1 or Pack2. And the AMR Pack was never fitted at the factory, always a dealer fit accessory. The AMR V12VS came with the parts as part of the standard AMR Spec, so whilst it was factory fitted it was not a "pack" as such.
Then you have models such as the AMR Rapide, which came with the 595bhp power as std but did have the secondary cats installed, whereas the Vanquish S, (ironically not an AMR as such) also came with the 595bhp power as std but did NOT have the secondary cats.
It's a true minefield for any non AM Specialist to get their head around. And confusing at least for those of us in the know....
Thanks for the comments guys. The point I was simply trying to make was that the motorsport catalysts really do need to be hot to work, as a result of being designed to work under the high engine loads and speeds of race conditions. For this reason, it is possible to fail an MOT where the tester simply has to allow the engine to reach 'normal' road operating temp.
The experiment was to see what difference it makes to a borderline result at the 'normal' conditions associated with the MOT emissions tests if one gets the sports catalyst as hot as is possible, i.e. closer to its design operating parameters. The result was, perhaps as expected, that it does its job of cleaning up the gases much better.
The conclusion? Do your bit for the environment by opening the taps as often as you can...
For all our cars I drive 20 mins or so through to other side of town to MOT garage and usually have 15 mins spare for a nice run that goes up a steep hill on a dual carriageway after a mile or so and back down and get there a few mins before appointment and they run to time on 45 min slots.
Plus if car not driven much in weeks before it gets a little run out in the country the day before.
Plus if car not driven much in weeks before it gets a little run out in the country the day before.
I’m not sure that removing or changing OEM catalysts is a problem provided the car’s emissions remain under the set limits.
https://www.gov.uk/government/publications/modifyi...
https://www.gov.uk/government/publications/modifyi...
Caslad said:
I’m not sure that removing or changing OEM catalysts is a problem provided the car’s emissions remain under the set limits.
https://www.gov.uk/government/publications/modifyi...
Sorry but you are incorrect. Please read Section 8.2.1.1 a) of the MOT rules.https://www.gov.uk/government/publications/modifyi...
https://www.gov.uk/guidance/mot-inspection-manual-...
Any OEM emissions equipment, missing, obviously modified or defective is a Major Fail in itself.
AdamV12V said:
Caslad said:
I’m not sure that removing or changing OEM catalysts is a problem provided the car’s emissions remain under the set limits.
https://www.gov.uk/government/publications/modifyi...
Sorry but you are incorrect. Please read Section 8.2.1.1 a) of the MOT rules.https://www.gov.uk/government/publications/modifyi...
https://www.gov.uk/guidance/mot-inspection-manual-...
Any OEM emissions equipment, missing, obviously modified or defective is a Major Fail in itself.
“ You only need to check components that are visible and identifiable‘
- primary cats are not this. Winner.
I've never heard of any AM failing under this rule I would hasten to add, but going back to my first post on this thread having had them modified is a failure if the MOT is actually done correctly.
I've never heard of any AM failing for the deletion of secondary cats either which is far more visible / obvious that and primary delete. That said if it was noticed and failed, reversing a secondary delete is a lot easier and faster to do than a primary, so both have their pros n cons.
I've never heard of any AM failing for the deletion of secondary cats either which is far more visible / obvious that and primary delete. That said if it was noticed and failed, reversing a secondary delete is a lot easier and faster to do than a primary, so both have their pros n cons.
AdamV12V
I have looked at the information you kindly shared. It appears that an inspection to determine missing, modified or defective OEM parts is only to be carried out on cars that must have a Full Catalyst Emissions Test.
Cars requiring the Full Catalyst Emissions test (according to Chart 2) are those which have failed the Basic Emissions Test.
Therefore if I understand it correctly, a car will be fine if the emissions are within the prescribed limits of the Basic Emissions Test irrespective of whether it has missing or modified parts.
I have looked at the information you kindly shared. It appears that an inspection to determine missing, modified or defective OEM parts is only to be carried out on cars that must have a Full Catalyst Emissions Test.
Cars requiring the Full Catalyst Emissions test (according to Chart 2) are those which have failed the Basic Emissions Test.
Therefore if I understand it correctly, a car will be fine if the emissions are within the prescribed limits of the Basic Emissions Test irrespective of whether it has missing or modified parts.
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