New 2nd Generation Mercedes B Class

[Heman75]

I had a 7g-tronic mated to a 3.5l v6.  

The 1st to 2nd gear clunks under certain acceleration situation. 

Put it in permanent sports mode seem to make it better. 

 

Beyond the 2nd gear the AT drives live a dream. 

u r right on the spot... i have to control my pressure on the pedal to make sure 1st to 2nd is smooth unlike the dct which is easier to control.. not so abrupt...

if I put in sports mode, I never get a chance to drive at gear6 or 7 .. keep at driving at gear5 due to slow traffic.

Edited October 17, 2016 by Heman75

[7hm]

The perception of poor 'smoothness' for DCT usually happens when the DCT is confused by or mispredicts driver action.

 

A DCT typically achieves a gear change within double digit milliseconds, resulting in a seemingly imperceptible shift with the lowest amounts of power loss due to disconnection of any transmission type yet by disengaging one clutch and engaging the other simultaneously.

 

But due to their design, DCTs usually pre-select gears based on prediction, and their pre-selection process usually happens on the presently non-engaged gear-set. Typically a DCT preselects the next higher gear if it detects the driver as accelerating or preselects a lower gear if decceleration or braking is detected. The issue is that DCTs these days don't have discretion of a seasoned manual driver; the preselection takes place in a fashion similar to the older automated single clutch boxes; that is to say slowly and jerkily... like a newbie driver - rough engagement of the clutch.

 

So if the gearbox mispredicts driver action, it has to make up for it by choosing the right gear, which takes much longer than the simple clutch switchover which would be what is happening with a correctly predicted and preselected gear, perhaps even longer than conventional torque convertor boxes do. Or worse, if it has to step down two gears, meaning it has to select another gear on the currently engaged clutch, it typically executes the action even more uncomfortably.

 

It also depends on your definition of "smooth". Smooth acceleration, without interruptions? DCT is best. Smooth and consistent gear changes? Conventional autos might be better.

[therock]

Can I downshift two gears, so that it engages the engine brake, revs up as I enter a bend?

Or when I go downhill, I downshift two gears from 5 to 3?

Any damage to the DCT gearbox? 

Thanks

[7hm]

Can I downshift two gears, so that it engages the engine brake, revs up as I enter a bend?

Or when I go downhill, I downshift two gears from 5 to 3?

Any damage to the DCT gearbox? 

Thanks

In this regard, simply treat it the same as you would a conventional manual gearbox, their operating principle is similar. Just be careful that you do not accidentally redline in this manner, but I expect the 7G-DCT to have programming that rejects overambitious downshifts.

[therock]

Thanks, this video has been used to educate DCT users, I think it's quite useful:

[gsanglan]

Thanks, this video has been used to educate DCT users, I think it's quite useful:

 

Interestingly, it mentioned that driver should avoid inching the car forward for cars with DCT. But in traffic jam condition, this is unavoidable.

[7hm]

Interestingly, it mentioned that driver should avoid inching the car forward for cars with DCT. But in traffic jam condition, this is unavoidable.

This is why I feel DCTs are not suitable for our country which has some of the worst rates of inching conditions, unless you are taking routes or driving at times that avoid such situations.

[Silverkris]

Thanks, this video has been used to educate DCT users, I think it's quite useful:

 

Actually, the advices apply to all gear-boxes, not only DCT/DSG. The advices are basically correct as not to do "half clutches" often when inching forward, but this will also apply to the other gear boxes as well. Slowly inching forward will result wear-and-tear in all clutches, not only DCT/DSG. Remembering how we learn half clutch using manual gearboxes when we took our driving lessons?

 

As to which gear box is the best out of manual / convention auto / CVT / DCT/DSG, it really depends on the engine and purpose of the car the manufacturer intends (fuel efficient? power efficiency? performance? driver engagement?).

 

If you ask me, best gearbox should be those in the F1 cars (similar but not totally same as DCT, since the gear changes are still manual), where the gearbox is able to take on the power of the engine seamlessly.

[therock]

More places to shop for B Class accessories: 

http://www.parts.loc8apart.co.uk/nav/auto-part/CA/Mercedes-Benz/B-Class/Clutch-Slave-Cylinders.php

[Hamburger]

dont inch forward with DCT...go JB how?

 

Flintstone huh...

Edited December 3, 2016 by Hamburger

[therock]

No more B Class?

https://www.google.com.sg/amp/www.drive.com.au/amp/motor-news/mercedesbenz-bclass-to-be-renamed-20150114-12o9i5.html?client=safari

[Silverkris]

No more B Class?

https://www.google.com.sg/amp/www.drive.com.au/amp/motor-news/mercedesbenz-bclass-to-be-renamed-20150114-12o9i5.html?client=safari

You are referring to a news in 2015.

Moving on, they will not classify the B class under A class because it will dilute A class instead.

But I do hope if news of a + is in progress, A "B+" with 7 seats will not be a bad idea.

[therock]

Yeah a 7 seater will be very welcome. Extend the current chassis by a bit and you can compete with the BMW GT.

[L23]

Yeah a 7 seater will be very welcome. Extend the current chassis by a bit and you can compete with the BMW GT.

They already have 7 seater. R280

[therock]

They already have 7 seater. R280

That's a totally different size class, and it's no longer on sale:

https://en.wikipedia.org/wiki/Mercedes-Benz_R-Class

[Silverkris]

I think the V-class is more like it.

http://www.mercedes-benz.com.sg/content/singapore/mpc/mpc_singapore_website/enng/home_mpc/passengercars/home/new_cars/models/v-class/v-class/facts/comfort/interior.html

 

Its more like  Estima than a Wish, but the interior IS FANTASTIC!

[therock]

Just saw a nice red SLH B180 flash past me.. nice !

Edited December 24, 2016 by therock

[therock]

I guess the boat has landed :)