4.0 V8 Secondary cat delete
Discussion
Dunno about fitment with the DB11, but ive been using RP motorworks secondary decats on my 4.7 and then V12V. Great quality.
https://www.rpmotorworks.co.uk/search.asp
https://www.rpmotorworks.co.uk/search.asp
Thats pre 2021 facelift so you need these secondary decat pipes https://www.rpmotorworks.co.uk/products/130/aston-...
Edited by bogie on Wednesday 29th April 13:14
gdawwg said:
Perfect, i will get an order in, thanks
Just to check you are aware...those decat pipes will leave you with no cat at all. Which makes it technically illegal in the UK.Its an MOT failure and MAY invalidate all but 3rd party insurance.
The legal option would be what is often called 'racing cats' ie much reduced cell count.
Its your car and your risk. Im not saying dont do it. Just be aware
There are 4 catalytic converters on >2012 Vantages (and DB9, V12V, Vanquish) 2 primary cats with sensors, 2 secondary cats without sensors.
The secondary cats are really only needed for some other countries with stricter emissions tests.
The car will pass a UK mot emissions test without the secondary cats. The primary cats are doing most of the work.
Aston Martin used offer "official" AMR secondary decats as optional upgrades, and some AMR models came with them fitted from the factory.
If you had a particularly thorough MOT tester who was willing to remove the undertrays and inspect the full exhaust system, compare it to the OE fitment, then yes, technically they could fail the MOT because you have changed the emissions systems away from OE.
The secondary cats are really only needed for some other countries with stricter emissions tests.
The car will pass a UK mot emissions test without the secondary cats. The primary cats are doing most of the work.
Aston Martin used offer "official" AMR secondary decats as optional upgrades, and some AMR models came with them fitted from the factory.
If you had a particularly thorough MOT tester who was willing to remove the undertrays and inspect the full exhaust system, compare it to the OE fitment, then yes, technically they could fail the MOT because you have changed the emissions systems away from OE.
Marc_G said:
Just to check you are aware...those decat pipes will leave you with no cat at all. Which makes it technically illegal in the UK.
Its an MOT failure and MAY invalidate all but 3rd party insurance.
The legal option would be what is often called 'racing cats' ie much reduced cell count.
Its your car and your risk. Im not saying dont do it. Just be aware
Deleting the Particle filters is certainly considered “ illegal “ in the UK which is why all the companies that sell them plaster their adverts with “ only suitable “ for track and or off road vehicles. Its an MOT failure and MAY invalidate all but 3rd party insurance.
The legal option would be what is often called 'racing cats' ie much reduced cell count.
Its your car and your risk. Im not saying dont do it. Just be aware
In reality I’ve no idea what actually happens at the MOT but presumably it’s a fail due to the emissions by themselves ?
The other option is to get “ cat back “ alternatives.
bogie said:
There are 4 catalytic converters on >2012 Vantages (and DB9, V12V, Vanquish) 2 primary cats with sensors, 2 secondary cats without sensors.
The secondary cats are really only needed for some other countries with stricter emissions tests.
The car will pass a UK mot emissions test without the secondary cats. The primary cats are doing most of the work.
Aston Martin used offer "official" AMR secondary decats as optional upgrades, and some AMR models came with them fitted from the factory.
If you had a particularly thorough MOT tester who was willing to remove the undertrays and inspect the full exhaust system, compare it to the OE fitment, then yes, technically they could fail the MOT because you have changed the emissions systems away from OE.
When I had my V12S secondary decatted from new it was replaced with the QS straight through pipes and AM put in writing this would not impact the warranty or indeed MOT.The secondary cats are really only needed for some other countries with stricter emissions tests.
The car will pass a UK mot emissions test without the secondary cats. The primary cats are doing most of the work.
Aston Martin used offer "official" AMR secondary decats as optional upgrades, and some AMR models came with them fitted from the factory.
If you had a particularly thorough MOT tester who was willing to remove the undertrays and inspect the full exhaust system, compare it to the OE fitment, then yes, technically they could fail the MOT because you have changed the emissions systems away from OE.
alscar said:
When I had my V12S secondary decatted from new it was replaced with the QS straight through pipes and AM put in writing this would not impact the warranty or indeed MOT.
Yep, the secondary decat continues to be a popular mod for the VH Vantages. I bought my V12S used and the only mods are the exhaust switch and secondary decat pipes 
Cheers for the extra info guys. Didnt realise there were 2 additional cats!
Indeed, none would fail an MOT and be illegal, ditto removing the OPF.
To my knowledge there is no specific check for the presence of an OPF filter. But warning signs on the dash etc would trigger it.
I own a garage with an MOT bay...i guess I could ask next time im in!!!
Indeed, none would fail an MOT and be illegal, ditto removing the OPF.
To my knowledge there is no specific check for the presence of an OPF filter. But warning signs on the dash etc would trigger it.
I own a garage with an MOT bay...i guess I could ask next time im in!!!
These are the ones I've found, they're advertised for a DB11 but fairly sure they'd fit my 69 plate v8v..my only concern was around the OPF and if my car had them fitted or not, chat GPT seems to think I I have.
https://ebay.us/m/AJ1LVO
https://ebay.us/m/AJ1LVO
gdawwg said:
These are the ones I've found, they're advertised for a DB11 but fairly sure they'd fit my 69 plate v8v..my only concern was around the OPF and if my car had them fitted or not, chat GPT seems to think I I have.
https://ebay.us/m/AJ1LVO
Seems like a good discount over new. I cant answer for sure if the DB11 pipes are the same pattern as the Vantage, but Im sure RP Motorworks would confirm if you email them.https://ebay.us/m/AJ1LVO
Marc_G said:
Cheers for the extra info guys. Didnt realise there were 2 additional cats!
The cat thing can be confusing because the primary cats are built into the manifolds. The easiest option for a bit more noise on the post 2012 cars are the secondary decat pipes. They are also supposed to release another 10bhp or, not that I can notice
Good video here by Bamford Rose detailing the options: https://youtu.be/VG5KD1n5XYY?si=daEXgPEKv9JbeRz3
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