BMW's M6 Convertible could well be the ultimate 'one size fits all' automotive ballistic missile. Jonathan Crouch reports.
Ten Second Review
There aren't many performance cars as multitalented as BMW's M6 Convertible. Yes, it'll do the burbling boulevardier thing while you top up your tan, but switch it into attack mode and this 560PS weapon will demolish 62mph in little over four seconds and demonstrate body control you previously thought impossible in a nigh-on two-tonne soft top. It's a little lower key than its barking V10 predecessor but miles smarter.
Big convertibles have traditionally been a bit of a soft target. After all, putting together the constituents for a car that allows you to check out who's checking you out hasn't always taxed the finest brains in a car manufacturer's design division. A slinky shape, a potent-sounding V8 and you were pretty much set, but that has changed in recent years. Customers have become more demanding. They want cars that can do all that and entertain around corners too. Add to that the requirements for impeccable safety, excellent reliability and an interior laden with enough gadgets to keep the most exigent of button-prodders happy and building a great convertible has become a seriously taxing assignment. BMW's M6 Convertible never wanted for speed or complexity. The V10 powerplant was perhaps a bit hard-edged to carry off the boulevardier image with any great conviction though. Munich has solved this conundrum with its current M6 Convertible, a car with as many personalities as you've got time to explore.
That mighty powerplant tucked under the bonnet shouldn't come as any great surprise. We've seen it before in the M5 and this twin-turbocharged 4.4-litre V8 endows this four-door M6 with scorching straight line speed. BMW has striven to strip a bit of weight from the M6 and redistribute it in all the right places using parts like a bonded carbon reinforced plastic roof to lower the centre of gravity. Of course, it's sledgehammer quick, 560PS of power and 680Nm of torque will do that for you. The sprint to 62mph is smashed in just 4.3 seconds before a soft electronic limiter brings a halt to acceleration at 155mph. Specify the M Driver's Package and that limit eases out to 189mph. This is an engine with an almost turbine-like power delivery, and while it lacks the aural charisma of the old 5.0-litre V10, it more than makes up for that with its huge reserves of low-end torque, which peaks from just 1,500rpm. BMW designed both coupe and convertible models at the same time, so you can rest assured that this drop top has some serious body stiffness built into it. You'll feel it the first time you hit a cat's eye or an expansion joint. There's no header rail flex or twittering from the dashboard mouldings. The roof offers excellent insulation against wind noise and the surprisingly insistent engine note when fixed in place and decent thermal insulation on cold days too. It's not the quickest roof to fold, taking 19 seconds to stow into the boot, but it is fully automatic and can be operated at speeds up to 25mph so traffic light lowering isn't an anxious race against the greens. The M6 Convertible gets the excellent seven-speed Double Clutch Transmission (M DCT) which snaps through shifts in a blink and if you want even greater stopping power than the already impressive standard setup, you can pay to option ceramic brake discs.
Design and Build
The M6 Convertible features the same high quality retractable roof as the 6 Series Convertible, with its 'fin' architecture projecting into the rear section, enhancing the silhouette of the car. The heated vertical glass rear window retracts independently of the roof itself. It takes a little longer to raise the roof, that operation taking 24 seconds in all. There are three colours offered for the roof material; Black, Beige or Anthracite Silver fleck. Given that so much of the M6 Convertible is built from aluminium and composites, it's amazing that the car still weighs 1980kg. In addition to the high tensile steels used in the monocoque, the doors and bonnet are made from aluminium while the front wings are formed in plastic while the boot lid's built from fibreglass. At the front there's an M apron with wide air intake apertures directing air to the engine, while sharply contoured headlamps featuring the characteristic BMW Corona rings with Adaptive LED headlight technology sweep the path ahead. There's also a wide M kidney grille, with its black slats and shape inspired by the double spoke alloy wheels. The interior is beautifully executed, with good sightlines from the driving seat. The lightweight M Sport seats feature an integrated seat belt system, electric seat adjustment, a pneumatic lumbar adjustment and manually adjustable under thigh support. The cockpit is finished in Merino leather and the 300-litre boot can be extended by another 50-litres by dropping the rear seats.
Market and Model
BMW wants £99,825 for the M6 Convertible which puts it up against some very serious rivals. Few, if any, offer quite this car's span of talent though. At the comfort-oriented end of the spectrum of putative rivals are cars like the £143,000 Bentley Continental GTC V8 or the similarly expensive Aston Martin DB9 Volante, neither of which are as powerful or as rapid as the BMW. The more sporting choices are best represented by Porsche's Carrera 4S Cabriolet with PDK transmission, which is also £99,000 plus change or alternatively the Maserati GranCabrio Stradale which is over £111,000. Probably the closest rival in execution is the Mercedes-Benz SL63 AMG, which is about as quick as the BMW but again is priced at about £12,000 more. It's not always easy to position a car that costs as much as many homes as a value pick, but in context, the M6 Convertible just about pulls it off. Customers get dual-zone climate control, heated and multi-adjustable M Sport seats, the M-specific HUD, Extended Merino leather interior trim and BMW Professional Navigation with 10.2" colour screen. Customers can also specify 20-inch alloy wheels, M Carbon Ceramic Brakes, Internet, BMW Night Vision and a powerful Bang and Olufsen stereo.
Cost of Ownership
First the good news. The latest M6 is a good deal more fuel-efficient than the old V10 model. That said, there are probably bulk freight carriers or intercontinental ballistic missiles that are more fuel efficient than that car. EfficientDynamics technology encompasses a suite of fuel-saving measures on this car such as Auto Start-Stop, Brake Energy Regeneration and Active Aerodynamics, helping to reduce consumption and emissions by approximately 30 per cent. The M6 Convertible claims a combined fuel consumption of 27.4mpg with CO2 emissions of 239g/km. It's even got a decently-sized 80-litre fuel tank which means that your touring range extends out to over 420 miles in real world conditions. Most other things will be predictably expensive. Servicing isn't unmanageable, but drive it hard and you'll face a hefty tyre bill and insurance isn't going to be cheap at Group 50. Run an M6 Cabriolet over three years and it'll work out cheaper than its key rivals.
All too often in life we're faced with a decision. Criterion A or B? You can't always take both. That always used to be the case for cars. You either had a car that rode well or handled, that offered decent fuel consumption or punchy acceleration, that was keenly priced or agreeably well built. Nowadays we're getting used to squaring those particular circles and while it's unashamedly a high-end thing, the BMW M6 Convertible moves us into new territory with the sheer range of talents. As long as you're willing to spend the time to understand its at first dizzying combinations of different chassis, steering and gearbox setups, you'll be rewarded with a vehicle that can convincingly play the elegant GT role one moment and then be switched into a mode where it sniffs out apices, snarls out of corners and devours straights with a maniacal appetite. When BMW ditched the V10, we thought the M6 Convertible might have gone a bit soft. It hasn't. Its skill set just broadened enormously.