We have been cruising at exactly 120 kilometers per hour (75 mph) when we finally pass under an electronic overhead sign that displays the readout we've been waiting for: a circle with slashes through it. At virtually the same moment, the speed-limit readout on the head-up display also gives the go-ahead, and we floor it. The car gathers speed quickly but with little drama, and we settle in at a comfortable 240 km/h (149 mph), although there is more available. This seems like enough given the presence of slower traffic, and, indeed, every time someone pulls into the far-left lane to pass, we give the big carbon-ceramic discs a workout but then quickly regain our pace. Driving on an unrestricted-speed autobahn is an intense experience for the driver, but the two passengers seem unfazed. This is exactly the situation for which the BMW M6 Gran Coupe was born: high-performance driving while carrying two (or three) passengers in relative comfort.
Familiar M mechanicals
To create its four-door executive express, BMW's M division made essentially the same changes to the 6-series that it did to create its other two M6 models, the two-door coupe and convertible. At the heart of the M6 Gran Coupe is the 560-hp, twin-turbo, 4.4-liter V-8, which sits fractionally lower in the chassis than the V-8 in the standard car. It's paired with a seven-speed M-DCT dual-clutch automatic transmission and an Active M rear differential. (North American customers can specify a six-speed manual at no extra cost.) Unlike the 650i, the M6 cannot be had with xDrive all-wheel drive -- it's rear-wheel drive only. Of course the M6 Gran Coupe gets its own specific chassis tuning plus driver-selectable steering effort and damper firmness. The carbon-ceramic brakes are a pricey $9250 option, but the rotors are expected to last the life of the car. The M6 Gran Coupe rolls on 20-inch wheels wrapped with aggressive Michelin Pilot Sport rubber, 265/35ZR-20 up front and 295/30ZR-20 at the rear.
Aside from the 20-inch wheels (whose exclusive, twin-spoke design is not offered on other M6 models), the M6 Gran Coupe's other exterior giveaways include a restyled front fascia with larger air intakes and an M6-specific grille with twin chrome bars, a carbon-fiber rear diffuser, and an exposed carbon-fiber roof. The carbon-fiber roof means you can't get a sunroof, but it's there to save weight -- approximately 11 pounds compared with a steel roof -- and it helps lower the car's center of gravity.
That roof's inset center section is mirrored on the interior, where the Alcantara suede headliner is bisected by leather in the middle. As in other M6 models, the Gran Coupe is treated to more supportive seats that offer additional lateral support at shoulder level. The gear lever is surrounded by a series of buttons that let the driver instantly select steering effort, damper firmness, and throttle sensitivity (with three settings each), as well as the transmission shift speed and stability control. A readout below the tach helps you know which settings have been selected, and the driver can save two different combinations -- say, one for relaxed cruising and one for more intense driving -- with two M buttons on the steering wheel.
As you like it
Playing with those buttons alters the character of the M6 Gran Coupe to a limited degree. The steering, which features hydraulic assist rather than electric, is a little heavy in the sport-plus setting when wheeling through parking lots but is reassuringly firm during high-speed autobahn blasts. Commendably, the comfort mode is not overly light, but its failure to load up as you wind on more lock earns it a demerit. In any mode, though, the system is precise, which is a good thing because the Gran Coupe is a wide machine to guide along the narrow lanes of its homeland.
M6 Gran Coupe project manager Maximillian Ahme says that the Gran Coupe has different springs, dampers, and antiroll bars than the two-door M6 coupe. He describes the overall tuning as mellower, but the variable damper settings obscure any comparisons. In the fairly brief twisty, two-lane sections of our drive, the car exhibited excellent body control no matter what the damper setting. Sport-plus faithfully transmitted every minor road imperfection, but it likely would be very stiff over the crumbling pavement in many parts of the USA.
Americans are more likely to appreciate the 4.1-second 0-to-60-mph time -- that factory figure exactly matches the M6 coupe, despite the fact that the Gran Coupe is 170 pounds heavier. The twin-turbo V-8 pours out a mighty river of torque, with 502 lb-ft available from 1500 rpm all the way to 5750 rpm. Throttle response is fantastic, and turbo lag is a non-issue. The V-8 did seem more aurally subdued here than in the last M6 coupe we drove, but it could be because so much of our time with that car was spent at the track.
Mostly, though, the M6 coupe's character has been largely preserved in its new four-door sibling. In visiting its high-performance ministrations on the Gran Coupe, BMW's M division has created a new M flagship (starting price: $113,925). It's a fine high-speed, high-style shuttle for three -- or four -- that relishes the speed-unrestricted go signal.
2014 BMW M6 Gran Coupe
|Base Price:||$113,925 (including destination)|
|Engine:||4.4L twin-turbo V-8|
|Horsepower:||560 hp @ 6000-7000 rpm|
|Torque:||502 lb-ft @ 1500-5750 lb-ft|
|Curb Weight:||4430 lb|
|Fuel Economy:||15/22 mpg (manual), 14/20 mpg (automatic)|