The Alpina B6 Cabrio (F12) 4.4 V8 Biturbo Switch-Tronic is a high-performance luxury convertible produced by the German automotive manufacturer Alpina between 2012 and 2015. Based on the BMW 6 Series Convertible (F12), the B6 Cabrio represents Alpina’s interpretation of a grand touring experience, blending substantial power with refined comfort. It occupied the top echelon of performance within the 6 Series range, positioned above even the BMW M6 Convertible in terms of overall driving experience, focusing on a more luxurious and usable power delivery. This model is part of the broader F12 generation, which saw Alpina apply its signature modifications to both the coupe and convertible body styles.
Technical Specifications
| Brand | Alpina |
| Model | B6 |
| Generation | B6 Cabrio (F12) |
| Type (Engine) | 4.4 V8 (540 Hp) BITURBO Switch-Tronic |
| Start of production | 2012 |
| End of production | 2015 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Cabriolet |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption (economy) – urban | 13.2 l/100 km (17.8 US mpg, 21.4 UK mpg, 7.6 km/l) |
| Fuel consumption (economy) – extra urban | 7.5 l/100 km (31.4 US mpg, 37.7 UK mpg, 13.3 km/l) |
| Fuel consumption (economy) – combined | 9.6 l/100 km (24.5 US mpg, 29.4 UK mpg, 10.4 km/l) |
| CO2 emissions | 224 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 4.4 sec |
| Acceleration 0 – 62 mph | 4.4 sec |
| Acceleration 0 – 60 mph | 4.2 sec |
| Maximum speed | 317 km/h (196.97 mph) |
| Emission standard | Euro 5 |
| Weight-to-power ratio | 3.7 kg/Hp, 267.3 Hp/tonne |
| Weight-to-torque ratio | 2.8 kg/Nm, 361.4 Nm/tonne |
| Power | 540 Hp @ 5200-6250 rpm |
| Power per litre | 122.9 Hp/l |
| Torque | 730 Nm @ 2800-5000 rpm (538.42 lb.-ft. @ 2800-5000 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | M2/1 |
| 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-Turbo, Intercooler |
| Valvetrain | DOHC, Valvetronic |
| Kerb Weight | 2020 kg (4453.34 lbs.) |
| Max. weight | 2430 kg (5357.23 lbs.) |
| Max load | 410 kg (903.9 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 | 1373 mm (54.06 in.) |
| Wheelbase | 2855 mm (112.4 in.) |
| Front track | 1594 mm (62.76 in.) |
| Rear (Back) track | 1637 mm (64.45 in.) |
| Drivetrain Architecture | Rear wheel drive |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 8 gears, automatic transmission |
| Front suspension | Double wishbone, Transverse stabilizer |
| Rear suspension | Independent multi-link spring suspension with stabilizer |
| 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 | Front wheel tires: 255/35 R20 Rear wheel tires: 285/30 R20 |
| Wheel rims size | Front wheel rims: 8.5J x 20 Rear wheel rims: 9.5J x 20 |
Powertrain & Engine Architecture
At the heart of the B6 Cabrio lies Alpina’s meticulously engineered 4.4-liter V8 engine, internally designated as the M2/1. This engine is based on the BMW N63 engine but features significant modifications by Alpina, including twin turbochargers, a revised cooling system, and a bespoke engine management system. The engine utilizes direct fuel injection and Valvetronic technology, allowing for precise control of valve lift and timing, optimizing both power and efficiency. The twin-turbo setup delivers 540 horsepower at 5,200-6,250 rpm and a substantial 730 Nm (538 lb-ft) of torque between 2,800 and 5,000 rpm. This power is channeled through a ZF 8-speed automatic transmission, dubbed “Switch-Tronic” by Alpina, which offers both fully automatic operation and manual gear selection via steering wheel-mounted paddles. The transmission is specifically calibrated to provide smooth shifts and responsive acceleration.
Driving Characteristics
The B6 Cabrio’s driving experience is characterized by a blend of effortless power and refined comfort. The 4.4-liter V8 delivers a broad torque curve, providing strong acceleration in any gear. The Switch-Tronic transmission contributes to this, offering quick and seamless gear changes. While not as overtly track-focused as the BMW M6 Convertible, the B6 Cabrio offers more than adequate performance for spirited driving. The suspension, tuned for grand touring, provides a comfortable ride without sacrificing handling precision. The steering is precise and well-weighted, offering good feedback to the driver. Compared to the standard 6 Series Cabriolet or even the M6, the B6 offers a more relaxed and usable power delivery, making it an ideal choice for long-distance cruising.
Equipment & Trim Levels
The B6 Cabrio came exceptionally well-equipped as standard. Interior appointments included Lavalina leather upholstery, Alpina-specific interior trim (often featuring wood or carbon fiber), and sport seats with adjustable bolstering. Standard features also included a premium sound system, navigation system, and a host of driver assistance technologies. Optional extras included Alpina’s signature blue and green interior color schemes, extended leather trim, and a variety of customization options. The overall interior ambiance was one of understated luxury and craftsmanship.
Chassis & Braking
The B6 Cabrio’s chassis builds upon the BMW 6 Series platform, but with Alpina-specific modifications. The suspension features stiffer springs and dampers, along with a larger stabilizer bars, to improve handling and reduce body roll. The braking system utilizes ventilated discs on all four wheels, providing ample stopping power. The ABS (Anti-lock Braking System) is standard, enhancing safety and control. The car rides on staggered alloy wheels – 8.5J x 20 inches at the front and 9.5J x 20 inches at the rear – fitted with performance tires (255/35 R20 front, 285/30 R20 rear).
Market Reception & Comparison
The Alpina B6 Cabrio was generally well-received by automotive critics. It was praised for its powerful engine, refined ride, and luxurious interior. Compared to the BMW M6 Convertible, the B6 was often seen as a more comfortable and usable grand tourer, sacrificing some outright track performance for a more relaxed driving experience. Fuel economy, while not a primary concern for buyers in this segment, was respectable for a vehicle of this performance level. Reliability was generally good, benefiting from Alpina’s meticulous engineering and quality control.
Legacy
The Alpina B6 Cabrio (F12) remains a desirable vehicle in the used car market. Its combination of performance, luxury, and exclusivity has ensured its continued appeal to enthusiasts. The 4.4-liter V8 engine, while complex, has proven to be relatively reliable with proper maintenance. However, as with any high-performance vehicle, regular servicing and attention to detail are essential to maintain its condition. The B6 Cabrio represents a unique offering in the grand touring segment, blending the best of German engineering with Alpina’s signature touch.
