by Adam Lynton
The 2018 M6 Convertible is the final iteration of the soon to be defunct 6 Series luxury coupe, with the wick dialed up to 11 in the pursuit of high performance befitting the addition of an M badge. Stunning looks pair with excellent performance, courtesy of a 552 horsepower twin-turbo 4.4 liter V8, sending power to the rear wheels through the choice of either a dual-clutch seven-speed automatic transmission or for the purists, a six-speed manual. But in this league of large sports convertibles, the competition from the Mercedes-AMG S 63 Cabriolet, as well as the Maserati GranTurismo Convertible is tough. Can a mere 6 Series deliver on the good, or are you better off waiting for the forthcoming 8 Series?
The 2018 M6 convertible remains unchanged from 2017, while the two-door coupe version has been discontinued. The M6 was refreshed for the 2016 model year, and with the end now in sight, all focus has been on the development of the 8 Series rather than upgrading the aging M6.
The BMW M6 Convertible pairs its sleek styling with the aggression of a sporty GT and traditional BMW styling elements such as the double kidney grille, giving the convertible an immediate sense of aggression. The upswept LED headlights are subtle compared to some of the other models but ooze class. From the side, the long body rests on handsome 19-inch wheels before ending at the squarish rear which has a sporty rear bumper covering the signature M quad tailpipes. Along with blistered arches and lower ride height, M badging on the front fenders and a subtle carbon-fiber rear spoiler all hint at the performance potential, while a power-retractable soft-top roof completes the look.
The 2019 M6 convertible is a long car, but with a length of 192.8 inches on a 112.2-inch wheelbase it's shorter than the M6 Gran Coupe overall by 4.7 inches and rides on a wheelbase shorter by 4.5 inches, too. It measures 53.9 inches in height, with a width of 74.8 inches and a mere 4.2 inches of ground clearance, making it 0.1 inches lower than the Gran Coupe. With a curb weight of 4,515 lbs, the soft-top is 85 lbs heavier than its four-door counterpart.
The M6 convertible is a car for drivers who want to indulge in fairly insane levels of speed and performance in a luxurious setting, effectively equipping an M5 powertrain into a luxury convertible. To that end, under the hood lies an M-tuned twin-turbo 4.4-liter V8 cranking out 552 horsepower and 500 lb-ft of torque, and sending these figures exclusively to the rear wheels, making the M6 what could be the last ever RWD M car powered by a V8. There's more power to be unlocked, though, and by adding the Competition Package, the M6 is capable of cranking out 592 hp. Between the engine and the rear end, buyers get a choice of transmission - either a lightning-quick seven-speed dual-clutch automatic or to cater to the purists, a six-speed manual gearbox.
As enticing as the manual may sound, we'd recommend the dual-clutch auto. Not only is it quicker - 0-60 mph in 4.3 seconds to the manual's 4.4 - but with that much power on tap and a fair amount of flex from the convertible body, you'll want both hands on the wheel when things get hairy, and the dual-clutch is simply one of the best in the business at managing the aggression of the twin-turbo V8. Speaking of that V8, it's a vicious thing that winds up at the mere thought of more speed, and despite the M6 Convertible's hefty mass, performance is nothing short of exceptional. It may not sound quite as good as an AMG V8, but an average sounding V8 is still a V8.
The M6 coupe is in a bit of a niche class that tries to balance the performance and handling of a sports car with the size and luxury of a grand tourer. The M6 mostly succeeds thanks to the sublime engine, the number of driving settings, and the overall balance that the car has. Unfortunately, it's hard to beat physics, and at times the bulk and weight of the M6 can become a hindrance. While more than capable of tackling bends and corners at pace, there's definitely more flex than in the M6 Gran Coupe, and there's always the impression that the heavyweight M6 Convertible is tugging at the limits of adhesion, while electronic trickery and sticky rubber fight for survival. It's easy to break away with a prod of the throttle, inducing smokey oversteer, but dial back to eight-tenths and the suppleness of the open-top M6 gives it a special blend of open-top performance perfect for coastal cruises.
Fuel economy is usually a secondary consideration when buying a performance-focused V8 sports convertible, and the M6 is no different. The EPA estimates peg the consumption of the manual at 15/22/17 mpg city/highway/combined, making it surprisingly more efficient than the dual-clutch with figures of 14/20/16 mpg. With a gas tank capacity of 21.1 gallons and a premium unleaded requirement, expect a maximum range of 359 miles in mixed conditions.
The M6 is a four-seater by design, although it's really the front occupants that'll be most comfortable, with more than enough space to relax and travel in comfort thanks to 40.3 inches of headroom and 42.1 inches of legroom. Rear passengers will find it a tight squeeze with only 30.5 inches of legroom. They will also feel uncomfortable with the roof up thanks to only 36.5 inches of headroom, relegating their use to children only, or as extra storage, if needed. The front seats are 20-way power-adjustable with a memory function and have adjustable lumbar support, with the driver's seat getting a thigh extension. With the addition of the Executive Package, ventilated seats are also available, adding further comfort and luxury to the M6 package, while a choice of no fewer than 12 combinations of luxurious leather and six interior trim choices ensures supreme customization.
By virtue of the soft-top convertible roof, trunk space is scarce with only 10.6 cubic feet which are barely enough to fit a large suitcase thanks to the relatively shallow trunk space. That's with the roof closed, too, and opening the top further diminishes available space. For longer items, there is a pass-through that runs between the two rear seats to increase space.
The interior is more practical, with space for smaller objects and both doors having shallow pockets. There are also front cupholders and a rear console storage space with a USB port and wireless charger for convenience. The rear passengers get front seatback storage for their personal effects.
The M6 is packed with features and comes standard with keyless entry and ignition, adaptive LED headlights, automatic soft-close doors, auto-dimming heated mirrors, heated 20-way power-adjustable front seats with memory function, front and rear parking sensors, leather seats, and a rearview camera. In addition to the standard features, there's a multitude of optional features available as part of the various packages such as a heated steering wheel, a head-up display, ventilated and massaging front seats, lane departure warning, blind-spot monitoring, forward collision warning, as well as side and top view cameras.
Every luxury car is expected to have a state of the art infotainment system, and the M6 delivers with a 10.2-inch touchscreen with BMW's iDrive interface, fully equipped with AM/FM radio, Bluetooth connectivity, USB inputs, HD and satellite radio, onboard navigation, a built-in wi-fi hotspot, and wireless device charging. Sound quality is superbly managed by a 16-speaker Harman Kardon surround-sound audio system, while optionally, a Bang & Olufsen 16-speaker premium audio system is available. Apple CarPlay functionality is an optional extra, but unfortunately, Android Auto isn't available.
Neither the NHTSA and the IIHS have evaluated the M6 Convertible or any convertible 6 Series variants. However, BMW has equipped the M6 Convertible with a range of safety features, including beefed-up brakes to bring things to a halt before they get out of hand, while advanced stability and traction control systems prevent any of the four standard airbags from being called upon. Additionally, active blind spot detection, aide and top-view cameras, and a head-up display add an extra layer of safety and driver assistance.
The BMW M6 a stunning performance car to behold, whether the soft-top roof is in place or stowed away. It blends performance with luxury and refinement but struggles to establish itself as a key player in the segment. You get near-M5 levels of performance, but the added weight and reduced rigidity mean handling is vastly compromised, robbing it of true performance car statues. The open-top aura, meanwhile, lends itself towards comparison with the Mercedes-AMG S Class Cabriolet, against which the 5 Series-derived interior just feels cheap and unspecial. It may be well-equipped and adorned with high-quality materials, but for the asking price, we just wish the M6 Convertible felt a little more special. In its final iteration, there may be some great deals to be found, but we'd hold off for the forthcoming 8 Series Convertible.
There is only a single model in the BMW M6 convertible lineup, and it starts at an MSRP of $122,300 excluding licensing, taxes, registration and the destination charge. With the M6 not being continued into 2019, though, dealers may be open to negotiation to clear room on the showroom floor.
4.4-liter Twin-Turbo V8 Gas
The 2018 BMW M6 Convertible is a single trim car that comes in rear-wheel drive with a twin-turbo 4.4-liter V8 engine which makes 552 horsepower and 500 lb-ft of torque. It comes standard with a dual-clutch seven-speed automatic transmission or an optional six-speed manual transmission. Based on the 6 Series convertible, it has been given the legendary BMW M tuning treatment to enhance performance and handling, as well as upgraded styling to match.
The M6 comes standard with heated 20-way power-adjustable front seats with memory function, adaptive LED headlights, keyless entry and ignition, auto-dimming heated mirrors, automatic soft-close doors, front and rear parking sensors, leather seats, and a rearview camera. It also has a 10.2-inch touchscreen with onboard navigation, Bluetooth connectivity, AM/FM radio, wireless charging, Wi-Fi hotspot, a USB port, HD Radio, SiriusXM Satellite Radio, and a 16-speaker Harman Kardon sound system.
Mercedes Benz is a constant thorn in BMW's side, and for nearly every BMW model, there's a Mercedes to compete. In this case, it's the AMG S63 Cabriolet. The S63 starts at a much higher price of $179,500 compared to the M6's $122,300, but the S63 is powered by a sonorous 603 hp twin-turbo 4.0 liter V8 delivering smoother performance and a better soundtrack. While the M6 is strictly rear-wheel drive and has the option of a six-speed manual transmission, the S63 only comes in all-wheel drive and with the automatic transmission - limiting, but more refined. Both offer up immense performance, but the Mercedes feels leagues above the M6 in terms of a refined, luxurious interior, higher levels of comfort, more tech, and a greater sense of style. The M6 just feels cheap in comparison, and in this segment, buyers want luxury.
The Maserati GranCabrio brings Italian style to the luxury GT segment with its flowing lines and Italian sports car looks. It starts at a price of $148,850 compared to the BMW's $122,300. The GranTurismo Convertible is strictly rear-wheel drive and comes with a 454 horsepower 4.7 liter V8 connected to a six-speed automatic transmission. It may be slightly slower than the M6 looking strictly at the figures, but the sound of the Italian V8 is hard to ignore, giving the GranCabrio a greater sense of occasion than the M6. The interior of the Maserati also has Italian flair with an abundance of leather and a more sporty feel compared to the business-like and frankly boring approach of the M6. There's no doubt that the Maserati turns more heads and has a more exclusive image. It's an elegant driving machine that makes every journey feel like an occasion. On the other hand, the M6 is more of a functional driving machine. It may lack the glamour of the Maserati, but it makes up for it in brilliant driving dynamics and more power.