[westphone]

So looking at numbers for numbers sake, we did a little experiment here. It is by no means worthy for Road & Track, but....
AT M135i gets 17.x km trying to get the best mileage, MT just can't I guess because the final gear MT being 0.8xx and the AT being 0.6xx with the same final ratio.

Let's continue this "Efficient Dynamics" theme throughout the range for 114i on up there is no consideration for putting on DCT eh? I wonder why that is because doesn't DCT eliminate torque converter like those in a regular albeit a very good AT, it's sorta like going "all the way" eliminating inefficiencies cutting out torque converter? Perhaps cost, usable life (not trying to insinuate VW with their problems), comfort? Opinion always welcomed and thanks in advance Marketing wise I think it would be a weaker reason because they could have just called it something else, and they don't seem to mind letting M135i using the ratios from the 1M (ok it is the "same" gearbox )

I personally think it's a combination of all three of them, and AT they have just gotten so good with it....

[logiclee]

The 8AT can lockout the torque converter from 1200rpm in 1st and 2nd gear and lock it out totally in the other 6 gears.
The new dual vane cell pump is very efficient, ZF say the 8AT is more efficient and lighter than a 7 speed wet clutch dct.

Cheers
Lee

[HighlandPete]

Originally Posted by logiclee

The 8AT can lockout the torque converter from 1200rpm in 1st and 2nd gear and lock it out totally in the other 6 gears.
The new dual vane cell pump is very efficient, ZF say the 8AT is more efficient and lighter than a 7 speed wet clutch dct.

Cheers
Lee

In addition to your comments, which are big leaps forward in efficiency...

From my reading, not every one likes the DSG/DCT type boxes for low speed driving, parking, etc., as there can be issues with some of the designs. Torque converters have the ability to give super smooth low speed manoeuvres. The fluid coupling still has some advantages.

HighlandPete

[KoenG]

Don't understand why a normal dry clutch in a DCT is more efficient compared to a fast locking torque convertor. Both produce losses by friction, like every clutch does... For smoothness and precision, both are competing, but the ZF transmission is a winner to my opinion.

In the (recent) past you had a lot of massive inefficient torque convertors, but slip was required since:
1. Engines didn't have torque at low rpms.
2. Control was not microchip controlled, without having all relevant variables of the engine, inputs of the driver and six degrees of vehicle freedom. So no clue what the driver wants and where the vehicle is going!
3. Only 4 or 5 gears, in combo with point 1 providing for massive torque drops with every gear shift!

All this has evolved dramatically last decade.

[Fanis]

Originally Posted by HighlandPete

From my reading, not every one likes the DSG/DCT type boxes for low speed driving, parking, etc., as there can be issues with some of the designs. Torque converters have the ability to give super smooth low speed manoeuvres. The fluid coupling still has some advantages.

I am one of the people who do not like DCT type gearboxes and I much prefer traditional ones with torque converter. If I want an automatic I want a proper one, not an automated manual gearbox.

[tawia]

Originally Posted by Fanis

I am one of the people who do not like DCT type gearboxes and I much prefer traditional ones with torque converter. If I want an automatic I want a proper one, not an automated manual gearbox.

AMG

[Fanis]

Originally Posted by tawia

AMG

[westphone]

Originally Posted by tawia

AMG

I suppose the comparison of the upcoming A45 AMG / CLS45 uses a double clutch system is being compared?

The only Merc I ever driven is someone's C class, but that's a full automatics....