M4 & GTS DCT differences

[aboulfad]

So the hardware is identical (check etk, ASAP, ...), same clutches, mechatronics, housing unit, also identical gear ratio according to this and this.

The F82 GTS tech info Section 4.5:

For power transmission, the F82 M4 GTS uses the M double-clutch transmission M DCT Drivelogic also optionally available for the F82 BMW M4 Coupé without any design modifications. The shift characteristic of the 7-speed M DCT Drivelogic was made even more suitable for motor sports driving and matched specifically to the F82 M4 GTS.

Given the power/torque increase over the M4, what is this "shift characteristic for motor sports, is it mostly the "clutch clamping" thingy?

[OutlawX3M]

IMO if the hardware is identical then it's software.

Perhaps different shifting programming to account for the increase HP + TQ because the GTS has a different hp + TQ curves. That may change where the optimal power is so they adjusted the shift points in the DCT.

[Bucketsbentley]

While the M4 and M4 GTS share the same gearbox, the gearbox was updated as of this month for both M4 and M4 GTS (new parts number). There was a previous update in March. The oil pan and oil windage tray are also new for both models.

[dr.mba]

Originally Posted by Bucketsbentley

While the M4 and M4 GTS share the same gearbox, the gearbox was updated as of this month for both M4 and M4 GTS (new parts number). There was a previous update in March. The oil pan and oil windage tray are also new for both models.

Interesting... So does this affect F80/M3 as well? I assume it's the same transmission after all.

M

[Bucketsbentley]

Originally Posted by dr.mba

Interesting... So does this affect F80/M3 as well? I assume it's the same transmission after all.

M

Yes same transmission

[dgp]

Originally Posted by Bucketsbentley

While the M4 and M4 GTS share the same gearbox, the gearbox was updated as of this month for both M4 and M4 GTS (new parts number). There was a previous update in March. The oil pan and oil windage tray are also new for both models.

Any idea what's new under new gearbox?

[Bucketsbentley]

Originally Posted by dgp

Any idea what's new under new gearbox?

No idea. Best ask a BMW engineer

[aboulfad]

Originally Posted by Bucketsbentley

While the M4 and M4 GTS share the same gearbox, the gearbox was updated as of this month for both M4 and M4 GTS (new parts number). There was a previous update in March. The oil pan and oil windage tray are also new for both models.

Are you basing this statement purely on part number change? Sometimes parts numbers change without change in the part itself and vice versa.

http://www.realoem.com/bmw/enUS/show...diagId=28_0018

http://www.realoem.com/bmw/enUS/show...diagId=28_0018

[Bucketsbentley]

Yep part number change. As I said, best talk to a BMW engineer. Not clear what has been updated. BMW don't usually change p/n unless there's been an update of some kind

[CaryTheLabelGuy]

Originally Posted by Bucketsbentley

Yep part number change. As I said, best talk to a BMW engineer. Not clear what has been updated. BMW don't usually change p/n unless there's been an update of some kind

Part numbers can also change if there is a new supplier.

[Bucketsbentley]

Originally Posted by CaryTheLabelGuy

Part numbers can also change if there is a new supplier.

True but how many different suppliers are able to produce the DCT box to BMW standards. It's complex. Springs I can understand. I for one would be happy if there were no design changes but...

[CaryTheLabelGuy]

Originally Posted by Bucketsbentley

True but how many different suppliers are able to produce the DCT box to BMW standards. It's complex. Springs I can understand. I for one would be happy if there were no design changes but...

We aren't talking about a whole DCT transmission. We are talking about a few parts inside the DCT. Individual parts are often sourced from different suppliers.

The DCT used in the M2/3/4/5/6 is made by Getrag, BTW.

[aboulfad]

ok I dug a bit about these updated p/n, here's what I found:
- the DCT top level p/n are subject to TeileClearing, "TC":

The affected part is subject to TeileClearing in certain countries. Before the respective part is exchanged, a PuMA case must be generated and a TeileClearing release must be obtained. Detailed information is available in PuMA/DCS Net.

Here's the information from ETK on all the new p/n (AA0, AA9, AC1), so it seems that in order to replace the DCT under warranty after a PUMA requires a TC release for the following countries: CN, DE and ZA.

Its unclear why for these countries only, and under what conditions, issues, seeing as oilpan and hydraulic cover was changed, maybe because of oil leaks ? The PUMA case would detail more info.

[CanAutM3]

Originally Posted by CaryTheLabelGuy

We aren't talking about a whole DCT transmission. We are talking about a few parts inside the DCT. Individual parts are often sourced from different suppliers.

The DCT used in the M2/3/4/5/6 is made by Getrag, BTW.

You forgot a digit

[CaryTheLabelGuy]

Originally Posted by CanAutM3

You forgot a digit

That pesky little M2.

Fixed it!

[aboulfad]

Ok was at a BMW dealer and asked them about the DCT minor revisions, as far as they know, it's only the casing and only for those countries above. I am going to another dealer tomorrow, I'll ask them too! (Obviously not for that reason)