The BMW 6 Series Convertible (F12) 650i Steptronic, produced from 2011 to 2012, represented the pinnacle of open-top luxury and performance within the F12 generation. Positioned as the range-topping engine option, the 650i combined a potent V8 engine with BMW’s sophisticated 8-speed Steptronic automatic transmission. This variant aimed to deliver a grand touring experience characterized by effortless power, refined comfort, and a sporty driving dynamic. It served as a direct competitor to other high-end convertibles like the Mercedes-Benz SL-Class and Porsche 911 Cabriolet.
Technical Specifications
| Brand | BMW |
| Model | 6 Series |
| Generation | 6 Series Convertible (F12) |
| Type (Engine) | 650i (407 Hp) Steptronic |
| Start of production | 2011 |
| End of production | 2012 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Cabriolet |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption (economy) – urban | 15.5 l/100 km (15.2 US mpg, 18.2 UK mpg, 6.5 km/l) |
| Fuel consumption (economy) – extra urban | 7.9 l/100 km (29.8 US mpg, 35.8 UK mpg, 12.7 km/l) |
| Fuel consumption (economy) – combined | 10.7 l/100 km (22 US mpg, 26.4 UK mpg, 9.3 km/l) |
| CO2 emissions | 249 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 5 sec |
| Acceleration 0 – 62 mph | 5 sec |
| Acceleration 0 – 60 mph | 4.8 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Emission standard | Euro 5 |
| Weight-to-power ratio | 4.8 kg/Hp, 209.8 Hp/tonne |
| Weight-to-torque ratio | 3.2 kg/Nm, 309.3 Nm/tonne |
| Power | 407 Hp @ 5500-6400 rpm |
| Power per litre | 92.6 Hp/l |
| Torque | 600 Nm @ 1750-4500 rpm (442.54 lb.-ft. @ 1750-4500 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | N63B44A |
| Engine displacement | 4395 cm3 (268.2 cu. in.) |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 89 mm (3.5 in.) |
| Piston Stroke | 88.3 mm (3.48 in.) |
| Compression ratio | 10:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Direct injection |
| Engine aspiration | Twin-power turbo, Intercooler |
| Engine oil capacity | 9 l (9.51 US qt | 7.92 UK qt) |
| Coolant | 11.4 l (12.05 US qt | 10.03 UK qt) |
| Kerb Weight | 1940 kg (4276.97 lbs.) |
| Max. weight | 2390 kg (5269.05 lbs.) |
| Max load | 450 kg (992.08 lbs.) |
| Trunk (boot) space – minimum | 300 l (10.59 cu. ft.) |
| Trunk (boot) space – maximum | 350 l (12.36 cu. ft.) |
| Fuel tank capacity | 70 l (18.49 US gal | 15.4 UK gal) |
| Length | 4894 mm (192.68 in.) |
| Width | 1894 mm (74.57 in.) |
| Height | 1365 mm (53.74 in.) |
| Wheelbase | 2855 mm (112.4 in.) |
| Front track | 1600 mm (62.99 in.) |
| Rear (Back) track | 1665 mm (65.55 in.) |
| Ride height (ground clearance) | 123 mm (4.84 in.) |
| Drag coefficient (Cd) | 0.32 |
| Minimum turning circle (turning diameter) | 11.7 m (38.39 ft.) |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels of the vehicle. |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 8 gears, automatic transmission Steptronic |
| Front suspension | Double wishbone |
| Rear suspension | Independent multi-link suspension |
| Front brakes | Ventilated discs |
| Rear brakes | Ventilated discs |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Electric Steering |
| Tires size | 245/45 R18 96Y |
| Wheel rims size | 8J x 18 |
INTRODUCTION
The F12 650i Convertible debuted in 2011 as part of BMW’s revival of the 6 Series lineage. Built on the F12 platform, which also underpinned the 5 Series Gran Coupe, the 650i aimed to blend luxurious appointments with dynamic performance. The “i” designation signified a petrol engine, and the “Steptronic” denoted the inclusion of BMW’s eight-speed automatic transmission. This model occupied the top tier of the convertible range, offering a more powerful and refined experience than the 640i variant.
Powertrain & Engine Architecture
At the heart of the 650i lay the N63B44A 4.4-liter twin-turbocharged V8 engine. This engine represented a significant advancement in BMW’s V8 technology, featuring direct fuel injection, a valvetronic system for variable valve timing and lift, and twin scroll turbochargers. The direct injection system delivered fuel directly into the combustion chambers, improving efficiency and responsiveness. The twin-turbo setup minimized turbo lag and provided a broad, flat torque curve. The Steptronic 8-speed automatic transmission was a key component, offering smooth and rapid gear changes. It featured a torque converter lock-up clutch for improved efficiency and a manual shift mode for driver control. The transmission was programmed to adapt to driving style, providing both comfortable cruising and sporty performance.
Driving Characteristics
The 650i Convertible delivered a distinctly grand touring experience. The 407 horsepower and 442 lb-ft of torque provided effortless acceleration, with a 0-60 mph time of around 4.8 seconds. The Steptronic transmission contributed to smooth and seamless power delivery, making it ideal for long-distance cruising. While not as overtly sporty as some competitors, the 650i offered a balanced and engaging driving experience. The suspension was tuned to provide a comfortable ride without sacrificing handling precision. The steering was precise and well-weighted, providing good feedback to the driver. Compared to the 640i, the 650i offered a noticeable increase in performance and a more refined overall driving experience. The manual transmission options available on the 640i were not offered on the 650i, focusing solely on the automatic for a more luxurious feel.
Equipment & Trim Levels
The 650i Convertible came standard with a comprehensive list of luxury features. Standard equipment included leather upholstery, power-adjustable seats with memory function, a premium sound system, a navigation system, and automatic climate control. Optional extras included features like active ventilation for the seats, a head-up display, a Bang & Olufsen sound system, and various interior trim options. The convertible top was a fully automatic soft top, available in several colors. The interior design emphasized luxury and sophistication, with high-quality materials and meticulous attention to detail.
Chassis & Braking
The F12 650i Convertible featured a robust chassis designed to provide both rigidity and comfort. The suspension system consisted of a double wishbone front suspension and an independent multi-link rear suspension. This setup provided excellent ride quality and handling characteristics. The braking system consisted of ventilated disc brakes on all four wheels, providing ample stopping power. Anti-lock brakes (ABS) and electronic stability control (ESC) were standard features, enhancing safety and control. The car’s weight distribution was carefully optimized to improve handling balance.
Market Reception & Comparison
The 650i Convertible was generally well-received by automotive critics. It was praised for its powerful engine, refined ride, and luxurious interior. However, some critics noted that the car’s weight and size could make it feel less agile than some competitors. Compared to the 640i, the 650i offered a significant performance advantage, but at a higher price point. Fuel economy was also lower on the 650i due to the larger engine. Reliability reports indicated that the N63 engine, while powerful, could be prone to certain issues, such as oil leaks and cooling system problems, requiring diligent maintenance.
Legacy
The F12 650i Convertible remains a desirable vehicle in the used car market. Its combination of luxury, performance, and style continues to appeal to enthusiasts. The N63 engine, despite its potential maintenance needs, is highly regarded for its power and responsiveness. Regular maintenance and preventative care are crucial for ensuring the long-term reliability of this powertrain. The F12 generation 6 Series Convertible represents a high point in BMW’s grand touring heritage, offering a refined and engaging driving experience that continues to be appreciated today.
