Detune M157 in 2016 CLS63 to meet Euro 6C standard

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AndyM157

New Member
Joined
Jul 14, 2022
Messages
4
Location
London
Car
CLS63S AMG Shooting Brake
I have relocated to Hong Kong and need to take my CLS63S AMG Shooting Brake with me - the now-extinct body shape and the superb 5.5L V8 M157 engine are both too rare to just sell and leave behind. Since this was my personal car in the UK, until a month ago it could have be exempted from meeting the latest emissions standards (HK is currently testing to Euro 6C), but that exemption has since been terminated by the local authorities without warning.

I now have to find a way to detune the M157, which is already compliant with the original Euro 6 emissions standard, to meet the more stringent Euro 6C NOx requirements. Of course, I know this will impact both performance and drivability, but that bridge can be crossed once the car is over here.

I am looking for UK-based M157 tuning experts, either someone who has proven track record in re-programming the ECUs specifically to meet emissions requirements, or a combination of software changes and additional / replacement filtering hardware in the exhaust system to get NOx levels below the Euro 6C limits. Any referrals or offers to help will be gratefully received!
 
I have relocated to Hong Kong and need to take my CLS63S AMG Shooting Brake with me - the now-extinct body shape and the superb 5.5L V8 M157 engine are both too rare to just sell and leave behind. Since this was my personal car in the UK, until a month ago it could have be exempted from meeting the latest emissions standards (HK is currently testing to Euro 6C), but that exemption has since been terminated by the local authorities without warning.

I now have to find a way to detune the M157, which is already compliant with the original Euro 6 emissions standard, to meet the more stringent Euro 6C NOx requirements. Of course, I know this will impact both performance and drivability, but that bridge can be crossed once the car is over here.

I am looking for UK-based M157 tuning experts, either someone who has proven track record in re-programming the ECUs specifically to meet emissions requirements, or a combination of software changes and additional / replacement filtering hardware in the exhaust system to get NOx levels below the Euro 6C limits. Any referrals or offers to help will be gratefully received!
I have absolutely no idea who might be able to help with this but a thought occurred to me as I read your post. How will the appropriate authorities know whether the car complied with Euro 6C?

Do they test it (e measure actual exhaust emissions form the tailpipe), or do they rely on the manufacturers homologation information when the car was new?

If they rely on the manufacturer’s homologation then “detuning” it may not be sufficient. Good luck importing it 👍🏻
 
I have absolutely no idea who might be able to help with this but a thought occurred to me as I read your post. How will the appropriate authorities know whether the car complied with Euro 6C?

Do they test it (e measure actual exhaust emissions form the tailpipe), or do they rely on the manufacturers homologation information when the car was new?

If they rely on the manufacturer’s homologation then “detuning” it may not be sufficient. Good luck importing it 👍🏻
The current procedure, following the termination of long-standing testing exemptions for personal car imports (as opposed to commercial import of cars for sale), is to first get it tested at a recognised testing centre in the UK for emissions and noise against latest European standards, submit that with some HK government paperwork to the local equivalent of the Environment Agency, only then can the car go on a ship.

Once it gets to HK, it needs to go to a government facility to have the same tests repeated to validate what the UK tester wrote up in the export paperwork, and they better match, otherwise it's going on the next ship back to Southampton. Because of this, the detune will need to be fairly permanent to make sure it's repeatable 6 weeks apart.
 
Once you get it to HK can you then get it back to full power 😏

Thats assuming you can even get it to comply in the 1st place
 
I'd suggest you get in contact with MSL or GAD. They are both experienced in tuning the 157 and may be able to help de-tune it.
Russ
 
Following, sounds like a worthwhile project!

I spent 3 weeks in HK a few years ago, was expecting to hate it as I’d already grown tired of the busyness of London but absolutely loved it. Must be in my top 5 places.
 
I'd suggest you get in contact with MSL or GAD. They are both experienced in tuning the 157 and may be able to help de-tune it.
Russ
Thanks Russ, talking to MSL already as they're a Weistec dealer in the UK. Interestingly I found a California state executive order type-approving the M157 Tune product as not making the emissions numbers worse. Indeed, for some reason those numbers look better - not sure if I am reading it correctly. Here's the PDF of it, for those who are more technically minded!
 

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Once you get it to HK can you then get it back to full power 😏

Thats assuming you can even get it to comply in the 1st place
Yep, that is indeed the plan - hobble the poor car in a semi-permanent way so they pass the same tests twice in a 6-week period. Then reset it all back to factory. I have actually zero interest in modifying this fine, low-milage example of a beast!
 

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