Quote:
Originally Posted by Boss330
"Upgraded cooler with bigger fans", does that remind you of any current M-models as well?
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This is where it gets a little fuzzy: automatic transmissions traditionally overheat from prolonged high rpm usage where manuals or DCTs are quite robust in performance. Given that both transmissions have undergone regular fluid changes, I would assume that
1. materials used in auto/mt/dct transmissions are thermal conductors of different nature.
2. cooling system is not up to the task.
If you are into cars, you have probably encountered countless cases where one of the two has been the culprit for overheat->tow aftermath for those with tiptronic/auto at the track where MTs or DCTs rarely if never have these problems.
For a mechanical reason I assume, torque converters are heavier than DCT and much heavier than manuals. This current M5 has less weight most likely due to carbon fiber roof+ some aluminum chassis parts that they should have used long time ago. + the new DCT would have been the ideal package.
As for the vibration, it is a fluid coupling nonetheless, and much of drivetrain vibration is absorbed by 6-10 quarts of tranny fluid that is used to spin the turbine to connect the flywheel to the transmission, resulting in much smoother ride than any of DCT or MT (which does so with the use of spring damped pressure plate or flywheel) which is good for daily driving I suppose, but it doesn't feel lively enough for me. Characteristic is one very important factor in these cars you see..