Preview: Charged-up 2013 BMW M6 Cabriolet has major muscle

Preview: Charged-up 2013 BMW M6 Cabriolet has major muscle
A seven-speed dual-clutch gearbox is the only transmission offered, although as seen in previous M5s, rumours of a six-speed manual persist.
Jim Kenzie
By Jim Kenzie
Posted on June 15th, 2012
0 Comments

If the BMW M6 Cabriolet is not much more than the recently unveiled M5 sedan in a comely two-plus-two droptop body, it isn’t much less either.

Contrary to usual BMW practice, the Cabriolet version of the M6 arrives first — in Canada, later this month, just in time for the two weeks of bad skiing that constitutes our summer.

The Coupé comes a month or two later.

Pricing in Canada hasn’t been announced yet, but in the U.S., it starts at $113,100. Given the (again, outrageous) differential of $11,600 between the U.S. and Canadian prices for the mechanically similar M5 sedan, that should put our M6 Cab around $125,000.

Reviewing the M5 (now also M6) tech specs, the former utterly manic high-revving V10 engine has been replaced with a twin-turbo V8, which looks rather prosaic on paper — it uses essentially the same block as the cooking versions of the 4.4 litre in other 5, 6 and 7 models.

Purists may — heck, they will — pine for the days of M-specific engine blocks and individual throttle valves for each cylinder; the new engine has no throttle valves at all thanks to the addition of the Valvetronic valve opening system.

But that was then, this is now.

Still, stonking is as stonking does; a new turbocharger system, closer to that used on the X5 M and X6 M, dials power up to 560 horses, and peak torque to 500 lb.-ft., increases of 12 and 30 per cent respectively.

BMW says this is the most powerful engine ever fitted to a series-production BMW and that’s a pretty strong field.

And, it is expected to be some 30 per cent more fuel efficient, at least based on government-mandated testing protocols. Flog the thing (and why wouldn’t you?) and as with most smaller-displacement turbocharged engines, there probably won’t be that big a difference.

A seven-speed dual-clutch gearbox is the only transmission offered, although as seen in previous M5s, rumours of a six-speed manual for the U.S. (and, you’d expect, Canada) persist. Why people who presumably buy this car to go fast would prefer a system that makes the car go slower, I’m not entirely sure.

Three different shift programs are available in each of automatic (“D” for Drive) or manual (“S” for Sport) modes, to suit your mood at any particular time.

An electronically controlled limited-slip/locking “Active M” differential helps ensure this urge is delivered to the rear wheels in the most appropriate fashion.

The up-rated suspension components are more rigidly attached to the subframes/body than in normal 6 cars, to improve precision.

The electronically adjustable dampers and the hydraulically boosted steering again have three settings each — Comfort, Sport and Sport+.

Likewise, three choices for the electronic stability control system — “Full On,” “M Dynamic Mode” which allows a greater degree of hooliganism, or “Full Off — you’re on your own, dude.”

Big six-piston front brakes with single-piston rears try to keep all this under some sort of control.

Perhaps in response to criticism that M cars have typically been under-braked, BMW is offering carbon-ceramic brakes for the first time on an M car (and, as far as I know or can find out on short notice, on any BMW).

These are even bigger, have greatly increased fade resistance, have rotors that last almost forever, and they save nearly 20 kg.

Yes, they’ll cost — no official price yet but Internet rumours suggest $8,300 (U.S.) — and they will likely squeal more in town. But if you’re ever going to use your M6 on a track, this is the first option box you should check on your order form.

All of these system choices mean you should spend several leisurely hours reading your owners manual. Fortunately, BMW lets you program your favourite combinations of settings, and recall them at the touch of a thumb on one of two M buttons on the steering wheel.

Yes, one more than before, M1 and M2.

So you get the default set-up when you fire up for most normal driving; maybe have M1 set to “canyon-strafing” mode; then M2 for full-on track work.

As you wish.

A couple of hours on heavily-policed California two-lane twisties may not be the perfect place to wring out any M car.

But it could be worse: Ontario, for instance.

The first thing you notice about the M6 — any M car, really — is that it is serious. Looks serious. Feels serious. Sounds serious.

Interesting point there — this engine doesn’t sound like a typical V8. My co-driver, the always insightful Marc Lachapelle, said it reminded him of a Dodge Viper’s V10.

When a conveniently-parked Viper GTS roared away from our lunch stop, this was confirmed.

Now, I doubt BMW engineers deliberately tried to make it sound like a V10 in memory of the older M5 engine. It is likely mere coincidence, caused by the unusual exhaust system plumbing — the exhaust comes from inside the “vee,” rather than outside.

But then, so it does on the normal twin-turbo BMW V8 engines, and they don’t sound like this. Like I said: interesting, even if we don’t have a full explanation.

The car is plenty quick, although with 115 more horsepower than the 650i Gran Coupe xDrive, I would have expected more than a 0.2 second improvement in the 0-100 km/h time (4.3 versus 4.5).

Again — and I know this is a recurring theme — with a curb weight of 2,045 kg (4,508 pounds), well, you almost need dynamite to get this thing rolling.

Once you do, it handles remarkably well. The hydraulic steering is probably responsible for the big improvement in driver feel over the Gran Coupé, although the more tightly-connected suspension surely helps too.

The firm ride is more consistent with the nature of this car than in the more luxurious Gran Coupé, although it still is susceptible to those bigger potholes.

In summary, the M6 Cabriolet a beautiful, fast, convertible sports car with a modicum of practicality to help justify itself.

A brief luncheon discussion with BMW North America CEO Ludwig Willisch offered a possible road map for the future on the weight issue. Along with Lachapelle, we were chatting about BMW’s retreat from aluminum structures, and he hinted somewhat conspiratorially that they’re looking beyond aluminum.

When we mentioned the carbon fibre roof panel in the M3 CSL, he smiled enigmatically and volunteered that the upcoming electric “i cars” will be thusly built.

We may have our clue.

Seems a shame it’ll be several years before that technology reaches the M cars.

I’m pretty sure it will be worth the “weight.”

Transportation was provided for freelance writer Jim Kenzie by the manufacturer. Email jim@jimkenzie.com

BMW M6 Cabriolet

PRICE (est.): $125,000

ENGINE: 4.4 litre V8, double overhead camshafts, four valves per cylinder, variable cam timing on both intake and exhaust, twin turbocharged, intercooled.

POWER/TORQUE, (horsepower / lb.-ft): 560/500

FUEL CONSUMPTION (City/Highway, l/100 km): 16.1 / 11.3.

COMPETITION: Jaguar XK-R Convertible; Maserati Gran Cabrio Sport; Porsche 911 Turbo Cabriolet.

WHAT’S BEST: Handsome new styling; impressive handling for such a heavy car; new engine more powerful yet more efficient; vast number of performance permutations made easier to access via the “M” buttons.

WHAT’S WORST: Turbo engine loses some of the crisp throttle response of the former engine; using same engine block as regular BMWs takes away some of the (snob?) appeal; not significantly faster at semi-legal speeds than regular 650i; too heavy.

WHAT’S INTERESTING: Along with new M5 sedan, it’s the end of an era for naturally-aspirated M engines.

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