Quote:
Originally Posted by captainaudio
It is a "traditional" auto transmission in the sense that it has planetary gear sets and a torque converter so its technologically similar to the "slushboxes" of years past but in terms of performance it is head and shoulders above the ATs of a generation ago. Due to the lock up of the torque converter once the car is moving, the extremely fast shift times, auto rev matching, etc. it gives the DCT a run for its money and tends overall to be smoother shifting (which contrary to public opinion is not a bad thing).
Things to take into consideration:
1. Both transmissions can shift faster than the blink of an eye which ranges from 300 to 400 milliseconds.
2. Both transmission shift faster than the best professional race drivers can shift a manual transmission.
3. Realistically, what are we doing with these cars on public roads where shift speeds that are faster than the blink of an eye will make a difference?
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1. Let's say it sometimes shifts around 200 millisecond=0.2 second. If any of the shift is done in this range the delay is noticeable enough to be uncomfortable, especially if you plan to track the car or drive at 9/10th.
I find torque converter in high torque applications inconsistent in shifting in especially the downshifts as the computer is trying to figure out the safest release point <7,400 rpm which doesn't cause oil cavitation in the gearbox. Getrag DCT on the other hand is rated <=9,000 rpm which is more than enough for any turbocharged engines, so it does not have this lag.
2. The complaint about dropping DCT is not having "fast enough" transmission in either case but rather going from "fastest, uncompromising shifts" of DCT to "fast enough" shifts of torque converter.
It might have worked with the grandpa community of M5-M8 buyers, but I refuse to buy an M car that has been compromised for cost cutting and daily smoothness. M340i is and should be the sole option for duality towards the daily driveability.
3. As I repeat, M stands for motorsport. If you putter around a town or floor it once in a while on the highway and don't drive the car 9 to 10/10th around tight corners of a track or mountain roads, M is just a poser car.
Having a trim level (competition, CS, etc) to separate the degree of hardcore in my opinion is an excellent choice, but the base has to be good to satisfy customers of all range. I've test driven N55 M2 DCT and it was one of the fastest, smoothest transmissions I've ever driven and is on the par with PDK on 718 Cayman GTS (also test driven). ZFat on F90 M5? Not even close.