LexFather

Dual clutch transmission... sounds complicated. And it is. Case in point: BMW's new DCT on its latest-generation M3. This new transmission from Munich is so complicated that apparently even BMW couldn't get it right the first time, so they're issuing a recall. The problem, as concluded by the National Highway Traffic Safety Administration, is that under hard braking the transmission's software is prone to initiate a multi-stage downshift, which could cause the car to stall. The solution, however, should be fairly simple, as BMW is asking all owners of 2008 or 2009 M3s equipped with the DCT (about 2,500 in the United States) to come in for a software update, free of charge, at their local dealership. After the software update, M3 owners can perform all the panic stops they want in smooth-shifting bliss.

http://www.autoblog.com/2008/11/20/b...lutch-gearbox/

8speed

Classic.....GT-R, now the E92 M3? Sounds like Lexus and the wicked 8 speed slusher in the IS-F is still the king! Bravo Skunk/TRD.....bravo!

TwiBlueG35

This is no big deal. But the newest BMW vehicles have some software issues here and there, may be the cars have been made too complicated. That's why sometimes I miss the simpler sports cars in the 80s and 90s.

8speed

If I just threw down 70k for a new M3 I would think it's a big deal

TwiBlueG35

Considering the simple solution this shouldn't be a big deal, but that's just me.

mmarshall

VW/Audi, though, managed to get their dual-clutch (DSG) right the first time. I consider it one of the best transmissions on the planet.

LexFather

I agree seems to be a simple fix but did you see when the car fails? Under heavy braking? WTF?

TwiBlueG35

Yeah it could turn out to be a serious accident. Well, as long as there is solution nothing more people could ask for.

mmarshall

Many sports cars of that period, except for maybe the Miata, really weren't that simple: Take the Mitsubishi 3000 GT VR4 and Dodge Stealth Turbo, for example. They had not only twin turbos, but a multi-adjustable suspension, AWD with a center differential, 4-wheel steering where the rear wheels turned opposite the front ones....even an adjustable valve for the exhaust tone. They were horrendous to work on, and made today's BMWs, mechanically, look simple.

8speed

No doubt.....didn't they get DSG from Lambo, or vice-versa? Audi/VW does have a nice bin of parts to choose from don't yeah think

mmarshall

That's probably because BMW brakes are so effective (especially the Sport package and M-Cars with Brembos) that with a really hard stop, the deceleration rate is so fast that the rate of automatic downshifts apparantly can't keep up with it. So, the car comes to a stop (or approaches a stop) with the transmission still lugging the engine in a higher gear, and, of course, with no manual clutch to disengage the engine yourself while you're braking, that's a perfect recipe for a stall.

Until the car is reprogrammed, my guess is that you could probably override the automatic downshift mode by just slipping the lever into N (neutral) when you brake so the engine doesn't stall, but under high-G braking loads, that might be difficult or impractical to try....and you damn sure don't want to by-pass Neutral and hit reverse by accident.

TwiBlueG35

Thanks for the enlightenment. But electronically and software speaking the newest BMWs seem too complicated.

8speed

Correct me if i'm wrong....but I don't think BMW M cars uses brembos

Compound brake system

A suitably powerful braking system for a car with this much performance was specifically developed for the new M3. The internally-vented, cross-drilled cast iron discs measure 14.2 inches in diameter at the front and 13.8 inches in the rear. Featuring large compound disc brakes and electronic anti-lock, stopping power for the new BMW M3 is strong, precise and consistent. They are connected to a floating aluminum hub by cast-in stainless-steel pins. This configuration reduces the thermal loads on the discs, thus increasing their performance and service life. An electrically-driven pump provides the system's vacuum power.

Service - and safety - is enhanced thanks to an integrated wear indicator which, through a dash display, allows the driver to monitor the condition of the brake linings. Brake service can thus be administered when necessary without guesswork.

Standard M-style light-alloy spoked wheels measure 18 x 8.5 inches with 245/40 low-profile tires at the front and 18 x 9.5 with 265/40 tires at the rear, can be supplemented by optional 19-inch versions in comparable widths and design.

CDNROCKIES

I might be loudly laughing my *** off....and crowing about how happy I am that I passed on the M3....but I don't want to jinx my IS F....karma can be quite the b***h

mmarshall

Thanks. I reviewed a new M3 back in April or May.......I thought I remembered it having Brembos. Even if not, though, the principle is still the same.....the brakes it DOES have are so effective (the M3 is a car with chassis and brakes that don't fool around) that it seems, to me at least, that
the problem is that the transmission can't downshift at the proper rate with the brakes, leaving the engine in too high a gear at too low a speed....and it stalls.

However, not being an engineer myself, I'll keep quiet now and let THEM decide how to handle it.