New M3's twin clutch transmission

[edb49]

So the cat is out of the bag, the E92 M3 will have a twin clutch transmission similar in concept to VW's DSG boxes. (Has previously been referred to as ZSG on other forums.)

In official terms:
7-speed M Double Clutch Transmission with Drive logic (M DCT Drivelogic)

The fact that it is a 7 speed is quite unusual for a DSG-type box. As far as I know, the Veyron is the only road going car to have had a 7 speed twin clutch box so far.

The box should give almost completely uninterupted shifts, which will knock anyhwere between 0.1s - 0.3s off the 0-60 time due to continual transmission of torque during the shifts. (For reference, the Golf GTI 0-60 improves 0.3s, and the TT improves 0.2s.) Having another ratio to keep in the power band will also help the acceleration times too.

Now, that bad news. Price has been mentioned as ~£2.5k elsewhere on this board, but there's no official information on this yet. I would guess it will be a similar premium to the original SMG upgrade on the E46 M3. Anyone know this figure? There will almost certainly be a weight penalty - all the extra complexity of two clutches etc adds 20kg to the VW DSG cars, so I would expect something similar on the M3. Finally, the word is currently that the E92 M3 at launch won't have this as an option, and production will only start in March 2008.

What other information is there about this box? Is it BMW's own design, or have they licensed the same BorgWarner boxes that VW use. The M-DCT will almost certainly be extremely popular with the majority of E92 M3 buyers, so the question is how will it affect the resale values of manual E92 M3s? Once the M-DCT box is actually available, what will be the percentage split of new sales? I'm second in line at my dealer for the M3, and I'm going to be holding out until the box is available, I have a feeling it will be fantastic.

[wrn]

I bought a new E46 M3 SMG II close to launch and I THINK the 'box was £1,750 extra.

I have the first M3 coupe and the first M3 cab into my dealership - so might take the manual coupe at launch and chop it on for a 'boxy cab in time for the summer? Probably not that expensive a way to do it...

Edited by wrn on Monday 9th April 10:38

[DoctorD]

Internal BMW correspondence confirms that the M-DCT box will only be available from March 2008, but since I will get a CSL when that is eventually launched I cannot wait until M-DCT is available, so will take a manual to be starting with. If I am able to swap this for a M-DCT car come March then I might consider doing so, otherwise I will wait for it in the CSL.

I seem to remember that there was a news leak on Ricardo Engineering's website just over a year ago, talking about a collaboration with BMW on a new gearbox. However there was also news that BMW had bought the DCT technology from Borg Warner. And finally just to confuse us, there is equally strong information to conclude that M-DCT is a Gertrag based system.

www.just-auto.com/article.aspx?ID=88902&lk=fs

Article said:

With Volkswagen having stolen a march on its competitors, the question now is who will be next? Well, according to CSM's intelligence, it will be a race between Ford Europe and BMW, with announcements expected before the end of 2006: Getrag-Ford has been developing two DCTs called the MPS6 (or DCT450), for use with L4 and V6 engines, and a shorter SPS6 (or DCT470) for use with the longer L5 (Volvo) engines. Meanwhile, Getrag has been developing a DCT called the 436 (or 7DCI600), which is to be supplied exclusively to BMW. The first application will be the BMW M3, which is powered by a new 307kW/412hp 'S65B40' gasoline engine. Thereafter, expect to see it in various BMW 3-Series and 5-Series cars. Following them will be a Getrag 481 (or 7DCL650) unit for Ferrari, and the much delayed ZF unit in the Porsche 911

What is not clear is perhaps if they may end up using several systems (i.e. Borg Warner system in mainstream BMWs, and Gertrag DCT system in M-models) just as they did with SMG (i.e. SSG was used in the 3-series, whilst SMG was unique to M-models).

Interestingly, Ricardo performed a benchmarking study of the SMGIII transmission back in 2005
www.ricardo.com/download/pdf/Ricardo_trans_bmw_001.pdf

Edited by DoctorD on Monday 9th April 10:53

[M5Dave]

I don't think the M-DCT box will have any great impact on the resale value of manual M3s.

I think there will always be a demand for manual M cars, in fact, I think many enthusiasts
are beginning to tire of the amount of technology that is crammed into these cars nowadays, as they feel it dilutes the driving experience.

The fact that the E60 M5 was only offered with an SMG box has probably cost BMW sales of this vehicle in the UK.

[wrn]

I agree that there will always be purists who want manuals - and that the residuals won't be impacted either way (residuals of 996 TTs are far lower than those with tip 'boxes, but I accept that that's because it's not a great 'box).

Personally I am a proper enthusiast - but if I was given the choice I'd have the clever 'box on an M3.

[edb49]

I do wonder if the M-DCT box will have different shifts modes? You're almost guaranteed an auto and manual mode, but what about the ferocity of shifts, etc?

[wrn]

I have no doubt that it will... the SMG II box had a few options and it's bound to at least match that...

[edb49]

wrn said:

I have no doubt that it will... the SMG II box had a few options and it's bound to at least match that...

I do wonder if that's going to be the case though. my understanding is that a DCT inherently gives extremely quick and very smooth changes, so you get the best of both worlds. What settings would you want to change?