onthelookout

Appreciate that response - certainly helpful to understand the potentials risks to vehicles with the modification completed. Assuming for a car with the TCU software already completed, the software portion could be reversed easily with a new flash / reset by a dealer or otherwise if no longer desired? And seeing the ~$4k package offered by RENNtech that you pointed out for the throttle blip / valve body update.

Doctodd33

yes can probably be reflashed/erased back to stock if you wanted to ensure the integrity/resale value of the car and/or avoid any transmission failure. Driving style probably also plays a role. I think ill just get an ECU tune and skip the TCU tune/rev match on my clk63bs because i cant justify it for $3750 from renntech. Ive had 2 of these cars and dont know what im missing, and still love the car... im fine with that.

onthelookout

The one thing I know I'm missing is a BS, which I'm trying to rectify (hopefully soon). But you're right, could ultimately have been nothing to do with the software given small sample size, or entirely the root cause (I also don't know the full backstory, but with parties no longer offering or out of business, leads me to believe something negative). Good to hear your insight on the tune though, and likely having to drive two cars back-to-back (one with, one without) to justify the cost of the modification from RENNtech.

Doctodd33

the m156 engine/transmission package is in other MB cars as well, which is a bigger sample size, and which are the ones i think had the transmission failures. Sorry but ive been reading so much it is hard to recall every detail of every post.

Suffice it to say ive decided against the rev match/tcu tune with my current clk63bs and will probably just do an ECU tune and air filters. My first CLk63bs(red one in my sig) was in 2009 and sold in 2011. I just bought my current one last year.

Tex5

The rev match can be done only by flashing both ECU and TCU. If you reflash the TCU do he dealer you will lost the rev match feature.

The TCU mod exists in several versions. On my previous non BS CLK 63 I had the v1.5, then I passed to V2
On my BS I think he told me it was the V3, which was not realized when they were still traveling to do rev match day at Weistec/Renntech etc.

My old non BS CLK had done more than 50 000km included track with the TCU mod without any gearbox issue
My TCI mod on the My CLK BS was done since 10 000km, mostly without any issue.

The improvement on up shift and downshift is for me more useful in S mode than in manual, with is still too slow to be really good

The valve body upgraded seems to be a simple upgrade with Sonnax parts
A workshop with good knowledge of the 722.9 could be able to do it for less than 4K

The other extreme solution is to retrofit the 722.9 MCT on a BS. EDok Performance had done it on a non BS CLK 63 but it is the same.

Derekm15

I was under the impression the BS had the “row” air box already with bigger filters

One of the 3 cars I test drove had a tune and headers it was snappy. I worry since the M156 is already tuned from the factory is pushing it more worth it?

Doctodd33

In the USA the BS does not have the row airboxes.

i installed weistec air filters and removed the charcoal filters and it lights up the traction control easier. SOTP also feels faster, but traction control lighting up easier is more objective. Search for "charcoal" on this subforum and lots of old good info comes up.