Sidv22

I have been planning to ask this question for a while but I have noticed that at slow speeds the transmission is pretty jerky in S and S+ mode to a point where the passengers feel uncomfortable . It is also noticeable in C mode but to a lesser extent. The jerks are noticed while taking foot off the throttle or while applying some pressure on throttle to increase speed in traffic. I did not have this issue in my 2009 C63 but for the most part, it was tuned. Does a tune play any part in reducing jerks? At my moment, my 2013 C63 is not tuned.
Any one experiencing the same issue? Any inputs will be appreciated.

zibby43

Your '09 C63 had an automatic transmission with a torque converter.

The MCT transmission in your 2013 (no torque converter; wet start-up clutch) is a bit more sensitive to throttle inputs.

DCT-equipped cars like the E90 or F80 M3 can be jerky as well in the more aggressive automatic settings.

With the MCT, in S and S+, you can't "***** foot" around with the throttle/pedal at low speeds in gears like 1st or 2nd. Lifting suddenly at slow/low speeds in S and S+ will cause the car to engine brake rapidly.

In those more aggressive modes, the transmission is designed to produce maximum performance so if you are just tapping the gas and then backing off the throttle in S or S+, you may encounter some surging/bucking.

My advice would be to keep the car in C while just cruising around town/driving in stop-and-go traffic.

Alternatively, you can also reset your transmission so that it can adapt to your driving style.

Sidv22

^^ Thanks a lot for your reply. That explains it then. I do drive in C mode when driving around town, especially in traffic but was annoyed at the fact that I couldn't enjoy S mode in stop and go traffic.
Btw, do you have a tune on your 2013? I had a eurocharged tune on my 2009 and it made 'night and day' difference. wondering if the same applies to 2012+ models.

JimmyR

I too have noticed a different feel at low speeds in the MCT transmission compared to the old transmission in my 2010 model. I notice it in stop start traffic, particularly when stationary and you first take your foot off the brake and lightly apply throttle the transmission almost shudders a bit as the car starts moving. Sort of like the sensation on a manual car when you start off in 2nd gear. I have just assumed this is a "characteristic" of the MCT, and fully expect to get the old "they all do that sir" when I bring it up at the next service.

zibby43

You are very welcome. I am preparing to install Eurocharged V5.

In my experience, tunes can improve shift points.

As I said in my initial reply, you can also reset the transmission software in an endeavor to have it "re-learn" your driving style/habits. This may smooth out some of the jerkiness in S and S+.

I predominantly use C, S+, and M. When I'm using S+, it is when I have room to "play" and I always commit to my launches in 1st gear. If you're aggressive with S+, you likely won't encounter any of the low speed jerkiness problems.

PeterUbers

Same here in my 2014 e63s

CPD SLK

I notice it in my 2009...it's annoying. It'll jump a little sometimes when I start getting on the throttle lightly...not sure if it has to do with my tune or not. I need to hit up Velos and see

Sidv22

Kinda glad its "normal". besides, you explained way better than me. Thanks
i am very interested in knowing your feedback once you tune it. I had no plan for a tune in the near future but might just jump on it.
also shot a PM to Eurocharged for further clarification.
so it seems that its not limited to the C63.
thats surprising. my 2009 shifting was very very smooth and more so after the tune.

ToXicXxX

Any car without a torque converter, and instead some form of clutch direct coupling system (be it wet starter, double clutch, or single clutch automated) you will get jerks when you play with the throttle.

Torque converters smooth out the process since they are a fluid coupling and able to absorb slight differentiations in input, mechanical couplings are an input:output system, they give what they get.

I learned this very quickly when I went from an automatic BMW 335i to a DCT BMW M3, you cannot play footsies with the car.

You may also notice a stutter if you play with the throttle too much, from the car rapidly engaging/disengaging the clutch or it slipping and failing to fully grip.

The guy with the 2009 doing this... You may have issues with your torque converter... Or you may be doing it at a high enough RPM (I think the automatic C63 goes direct drive after 2800 RPM?) to have a direct connection, causing a stutter. I know if I'm downshifting and I'm in 1st at 4000RPM and suddenly give it gas then let off, it will throw me around a bit.

The only auto-manual that I have not had this issue with is a B8.5 Audi S4... And I believe that's because it would gear into neutral when you let off the pedal in normal or sport mode.