The BMW M8 Convertible (F91) with the 4.4-liter V8 engine producing 600 horsepower and paired with the xDrive all-wheel-drive system and Steptronic automatic transmission represents the pinnacle of open-top performance within the second generation of the 8 Series. Production spanned from July 2019 to March 2022, positioning it as the most potent variant of the F91 convertible. This model aimed to combine the luxury and grand touring capabilities of the 8 Series with the high-performance characteristics expected of the M division. It sits at the top of the 8 Series convertible range, exceeding the performance of the 840i and offering a more focused driving experience than the standard 8 Series.
Technical Specifications
| Brand | BMW |
| Model | M8 |
| Generation | M8 Convertible (F91) |
| Type (Engine) | 4.4 V8 (600 Hp) xDrive Steptronic |
| Start of production | July, 2019 |
| End of production | March, 2022 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Cabriolet |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption (economy) – urban | 15.2 l/100 km (15.5 US mpg, 18.6 UK mpg, 6.6 km/l) |
| Fuel consumption (economy) – extra urban | 7.9-8.2 l/100 km (29.8 – 28.7 US mpg, 35.8 – 34.4 UK mpg, 12.7 – 12.2 km/l) |
| Fuel consumption (economy) – combined | 10.6-10.8 l/100 km (22.2 – 21.8 US mpg, 26.6 – 26.2 UK mpg, 9.4 – 9.3 km/l) |
| CO2 emissions | 241-246 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 3.4 sec |
| Acceleration 0 – 62 mph | 3.4 sec |
| Acceleration 0 – 60 mph | 3.2 sec |
| Acceleration 0 – 200 km/h | 11.3 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Emission standard | Euro 6 d-TEMP |
| Weight-to-power ratio | 3.4 kg/Hp, 298.5 Hp/tonne |
| Weight-to-torque ratio | 2.7 kg/Nm, 373.1 Nm/tonne |
| Power | 600 Hp @ 6000 rpm |
| Power per litre | 136.5 Hp/l |
| Torque | 750 Nm @ 1800-5600 rpm (553.17 lb.-ft. @ 1800-5600 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | S63B44 |
| 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 | 10 l (10.57 US qt | 8.8 UK qt) |
| Kerb Weight | 2010 kg (4431.29 lbs.) |
| Max. weight | 2440 kg (5379.28 lbs.) |
| Max load | 430 kg (947.99 lbs.) |
| Trunk (boot) space – maximum | 350 l (12.36 cu. ft.) |
| Fuel tank capacity | 68 l (17.96 US gal | 14.96 UK gal) |
| Length | 4867 mm (191.61 in.) |
| Width | 1907 mm (75.08 in.) |
| Width including mirrors | 2137 mm (84.13 in.) |
| Height | 1353 mm (53.27 in.) |
| Wheelbase | 2827 mm (111.3 in.) |
| Front track | 1627 mm (64.06 in.) |
| Rear (Back) track | 1632 mm (64.25 in.) |
| Front overhang | 950 mm (37.4 in.) |
| Rear overhang | 1090 mm (42.91 in.) |
| Minimum turning circle | 12.2 m (40.03 ft.) |
| Drive wheel | All wheel drive (4×4) |
| Number of gears and type of gearbox | 8 gears, automatic transmission M 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 | Front wheel tires: 275/40 ZR19 105Y XL Rear wheel tires: 285/40 ZR19 107Y XL |
| Wheel rims size | Front wheel rims: 9.5J x 19 Rear wheel rims: 10.5J x 19 |
INTRODUCTION
The BMW M8 Convertible (F91) 4.4 V8 xDrive Steptronic, launched in 2019, represents the high-performance convertible offering within the 8 Series lineup. Built on the GKL platform (shared with the 8 Series Coupe and Convertible), the F91 M8 Convertible aimed to deliver a thrilling driving experience without sacrificing the luxury and refinement expected from a grand tourer. It served as a direct competitor to vehicles like the Porsche 911 Turbo Cabriolet and the Aston Martin DB11 Volante. The “F91” designation specifically identifies the convertible body style within the broader M8 generation.
Powertrain & Engine Architecture
At the heart of the M8 Convertible lies the S63B44 engine, a 4.4-liter twin-turbocharged V8. This engine, a staple in BMW’s M division, utilizes direct injection and variable valve timing (Valvetronic) to optimize performance and efficiency. The twin-scroll turbochargers are positioned within the V of the engine, minimizing turbo lag and maximizing responsiveness. The engine produces 600 horsepower at 6000 rpm and a substantial 750 Nm (553 lb-ft) of torque available from 1800 to 5600 rpm. The engine’s architecture is longitudinal, meaning it’s mounted lengthwise in the chassis. The M Steptronic 8-speed automatic transmission is specifically tuned for the M8, offering quicker shift times and more aggressive programming than the standard 8 Series transmission. It features Drivelogic, allowing the driver to select from different shift profiles to tailor the transmission’s behavior to their driving style.
Driving Characteristics
The M8 Convertible’s driving experience is characterized by its immense power and sophisticated all-wheel-drive system. The xDrive system is rear-biased, providing a more engaging and dynamic feel. The 8-speed automatic transmission delivers seamless shifts, and the engine’s broad torque curve ensures strong acceleration in any gear. The 0-60 mph sprint is achieved in approximately 3.2 seconds, and the car is electronically limited to a top speed of 155 mph (250 km/h). Compared to the standard 8 Series convertible, the M8 offers significantly sharper handling and a more direct steering feel. While the added weight of the convertible top and all-wheel-drive system slightly impacts agility compared to the M8 Coupe, the M8 Convertible still delivers a remarkably capable and exhilarating driving experience. The gear ratios are optimized for both rapid acceleration and comfortable high-speed cruising.
Equipment & Trim Levels
The M8 Convertible came generously equipped as standard. Key features included Merino leather upholstery, M Sport seats with integrated headrests, a Bowers & Wilkins Diamond Surround Sound System, and a comprehensive suite of driver-assistance systems. The interior featured M-specific badging and trim elements, emphasizing the car’s performance credentials. Optional extras included a carbon fiber roof, extended Merino leather, and various customization options through BMW’s Individual program. The dashboard layout mirrored that of the standard 8 Series, with a 12.3-inch digital instrument cluster and a 10.25-inch central infotainment display. The convertible top was a soft-top design, offering a balance between weight savings and acoustic insulation.
Chassis & Braking
The M8 Convertible features a robust chassis designed to handle the engine’s power. The suspension utilizes a double-wishbone front axle and an independent multi-link rear axle, both with adaptive dampers. The suspension settings are adjustable, allowing the driver to tailor the ride comfort and handling characteristics. Braking duties are handled by large, ventilated discs at all four corners, with M Compound brakes as standard. Carbon-ceramic brakes were available as an option, offering even greater stopping power and fade resistance. The car also features an active differential, further enhancing traction and stability. Stabilizer bars are thicker than those found on the standard 8 Series, reducing body roll during cornering.
Market Reception & Comparison
The M8 Convertible was generally well-received by automotive critics, who praised its performance, luxury, and overall driving experience. However, some reviewers noted the car’s considerable weight and price tag. Compared to the M8 Coupe, the Convertible offered a similar level of performance but with the added enjoyment of open-top motoring. Fuel economy, while respectable for a vehicle of this caliber, was not a strong point, with combined figures ranging from 22.2 to 21.8 US mpg. Reliability reports have been generally positive, although the complexity of the engine and drivetrain means that maintenance costs can be significant. Compared to the 840i Convertible, the M8 offered a substantial performance upgrade, justifying its higher price for enthusiasts seeking the ultimate driving experience.
Legacy
The BMW M8 Convertible (F91) represents a significant achievement in high-performance convertible engineering. Its powerful engine, sophisticated all-wheel-drive system, and luxurious interior have cemented its place as a desirable collector’s item. On the used car market, well-maintained examples command premium prices. The S63B44 engine, while complex, has proven to be relatively reliable when properly maintained. The F91 M8 Convertible is likely to be remembered as one of the last of a dying breed – a high-performance, naturally aspirated (though turbocharged) convertible that delivers a truly engaging and rewarding driving experience.
