V12 Vantage exhaust

[handyman 1417]

Why does an MOT required to know anything about Astons? Do they have their own special test?

[AdamV12V]

Getting a bit like groundhog day in here...

Best you read this thread chaps!

https://www.pistonheads.com/gassing/topic.asp?h=0&...

[handyman 1417]

I someone takes their Aston for an MOT and it passes the emissions tests, why would a tester check for cat deletion and if the original cans are in situ, how on earth would he know?

[AdamV12V]

handyman 1417 said:

I someone takes their Aston for an MOT and it passes the emissions tests, why would a tester check for cat deletion and if the original cans are in situ, how on earth would he know?

Read the thread I posted above - it very clearly answers the questions are are asking here.

[handyman 1417]

AdamV12V said:

handyman 1417 said:

I someone takes their Aston for an MOT and it passes the emissions tests, why would a tester check for cat deletion and if the original cans are in situ, how on earth would he know?

Read the thread I posted above - it very clearly answers the questions are are asking here.

I have and other than having a pop at BR, it still doesn’t explain how or why an MOT tester would check for primary cat deletion if it passed the emissions test. I’m not pontificating whether cat deletion is right, wrong or necessary, just that there’s no justification for a tester to question the cats presence if the test is passed.

[LTP]

handyman 1417 said:

I have and other than having a pop at BR, it still doesn’t explain how or why an MOT tester would check for primary cat deletion if it passed the emissions test. I’m not pontificating whether cat deletion is right, wrong or necessary, just that there’s no justification for a tester to question the cats presence if the test is passed.

Because it's part of the MOT procedure for testers. The MOT Inspection Manual says:
8.2.1.1. Exhaust emission control equipment
You only need to check components that are visible and identifiable, such as catalytic converters, oxygen sensors, and exhaust gas recirculation valves.
You should reject all vehicles first used on or after 1 September 2002, where original emissions control equipment components are missing, obviously modified or obviously defective.

The actual emissions test (and the MIL light operation) is covered in section 8.2.1.2

https://www.gov.uk/guidance/mot-inspection-manual-...

[handyman 1417]

LTP said:

handyman 1417 said:

I have and other than having a pop at BR, it still doesn’t explain how or why an MOT tester would check for primary cat deletion if it passed the emissions test. I’m not pontificating whether cat deletion is right, wrong or necessary, just that there’s no justification for a tester to question the cats presence if the test is passed.

Because it's part of the MOT procedure for testers. The MOT Inspection Manual says:
8.2.1.1. Exhaust emission control equipment
You only need to check components that are visible and identifiable, such as catalytic converters, oxygen sensors, and exhaust gas recirculation valves.
You should reject all vehicles first used on or after 1 September 2002, where original emissions control equipment components are missing, obviously modified or obviously defective.

The actual emissions test (and the MIL light operation) is covered in section 8.2.1.2

https://www.gov.uk/guidance/mot-inspection-manual-...

On visual inspection, all the cats etc appear intact. If the cats had been removed and straight pipes put in their place, I’d agree, but we’re not discussing that option.

[LTP]

handyman 1417 said:

On visual inspection, all the cats etc appear intact. If the cats had been removed and straight pipes put in their place, I’d agree, but we’re not discussing that option.

I agree. But your question was:
it still doesn’t explain how or why an MOT tester would check for primary cat deletion if it passed the emissions test.

And the "why" answer is "because he's instructed to". And the "how" is "visually". If the catalyst cans in the manifolds are still in place and the O2 sensors not blocked off then I agree, it'll be down the the emissions test. But if you've got a fancy 6-2-1 manifold on each side with no cat can and the tester knows what should be fitted as OE then that's possibly a different situation, irrespective of the emissions result.

Edited by LTP on Saturday 9th March 22:57

[handyman 1417]

LTP said:

handyman 1417 said:

On visual inspection, all the cats etc appear intact. If the cats had been removed and straight pipes put in their place, I’d agree, but we’re not discussing that option.

I agree. But your question was:
it still doesn’t explain how or why an MOT tester would check for primary cat deletion if it passed the emissions test.

And the "why" answer is "because he's instructed to". And the "how" is "visually". If the catalyst cans in the manifolds are still in place and the O2 sensors not blocked off then I agree, it'll be down the the emissions test. But if you've got a fancy 6-2-1 manifold on each side with no cat can and the tester knows what should be fitted as OE then that's possibly a different situation, irrespective of the emissions result.

Edited by LTP on Saturday 9th March 22:57

I agree entirely with your point if such a manifold was fitted, however the threads covering this are mainly concerned with the BR technique of removing the catalyst material and leaving the original manifold and cans in place, therefore passing both visual and emissions tests. Again I’m not suggesting it’s necessary, justified, legal, ethical or otherwise, but simply such a procedure provides no concerns regarding an MOT carried out by a tester that’s never seen a V12 Aston or a main dealer.