The BMW 8 Series Convertible (G14) 840i xDrive Steptronic, produced from 2020 to March 2022, represents BMW’s re-entry into the large luxury convertible market. Positioned as a mid-range offering within the G14 8 Series Convertible lineup, it slots between the base 840i and the high-performance M8. The 840i aimed to deliver a blend of grand touring comfort, sophisticated technology, and engaging performance, appealing to buyers seeking a luxurious open-top experience without the extreme focus of the M model. It is built on the G14 platform, sharing components with the 8 Series Coupe and Gran Coupe.
Technical Specifications
| Brand | BMW |
| Model | 8 Series |
| Generation | 8 Series Convertible (G14) |
| Type (Engine) | 840i (333 Hp) xDrive Steptronic |
| Start of production | 2020 |
| End of production | March, 2022 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Cabriolet |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption (urban) | 9.8-10.2 l/100 km (24 – 23.1 US mpg) |
| Fuel consumption (extra urban) | 6.5-6.7 l/100 km (36.2 – 35.1 US mpg) |
| Fuel consumption (combined) | 7.7-8.0 l/100 km (30.5 – 29.4 US mpg) |
| CO2 emissions | 178-183 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 5.2 sec |
| Acceleration 0 – 62 mph | 5.2 sec |
| Acceleration 0 – 60 mph | 4.9 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Emission standard | Euro 6d |
| Weight-to-power ratio | 5.8 kg/Hp |
| Weight-to-torque ratio | 3.8 kg/Nm |
| Power | 333 Hp @ 5500-6250 rpm |
| Torque | 500 Nm @ 1700-4000 rpm (368.78 lb.-ft.) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | B58B30C |
| Engine displacement | 2998 cm3 (182.95 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 82 mm (3.23 in.) |
| Piston Stroke | 94.6 mm (3.72 in.) |
| Compression ratio | 11:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Direct injection |
| Engine aspiration | Twin-power turbo, Intercooler |
| Valvetrain | VALVETRONIC |
| Engine oil capacity | 6.5 l (6.87 US qt | 5.72 UK qt) |
| Kerb Weight | 1915 kg (4221.85 lbs.) |
| Max. weight | 2400 kg (5291.09 lbs.) |
| Max load | 485 kg (1069.24 lbs.) |
| Trunk (boot) space (minimum) | 350 l (12.36 cu. ft.) |
| Fuel tank capacity | 68 l (17.96 US gal | 14.96 UK gal) |
| Length | 4843 mm (190.67 in.) |
| Width | 1902 mm (74.88 in.) |
| Height | 1339 mm (52.72 in.) |
| Wheelbase | 2822 mm (111.1 in.) |
| Front track | 1627 mm (64.06 in.) |
| Rear track | 1642 mm (64.65 in.) |
| Ride height (ground clearance) | 118 mm (4.65 in.) |
| Drag coefficient (Cd) | 0.30 |
| Minimum turning circle | 11.6 m (38.06 ft.) |
| Drivetrain Architecture | All wheel drive (4×4) |
| Number of gears | 8 |
| Gearbox type | Automatic transmission Steptronic |
| Front suspension | Double wishbone |
| Rear suspension | Independent multi-link suspension |
| Front brakes | Ventilated discs |
| Rear brakes | Ventilated discs |
| Steering type | Steering rack and pinion |
| Power steering | Electric |
| Front tires | 245/45 R18 100Y XL |
| Rear tires | 275/40 R18 103Y XL |
| Front wheel rims | 8J x 18 |
| Rear wheel rims | 9J x 18 |
Powertrain & Engine Architecture
At the heart of the 840i xDrive Steptronic lies BMW’s B58B30C 3.0-liter inline-six engine. This engine is a member of BMW’s modular engine family, known for its smooth power delivery and efficiency. The B58 utilizes a single twin-scroll turbocharger, direct fuel injection, and BMW’s VALVETRONIC variable valve timing and lift system. VALVETRONIC allows for precise control of valve timing and lift, optimizing engine performance and fuel economy across a wide range of operating conditions. The engine produces 333 horsepower at 5500-6250 rpm and 368 lb-ft of torque from 1700-4000 rpm. The engine is longitudinally mounted at the front of the vehicle. The engine is paired with an 8-speed Steptronic automatic transmission, which features smooth and quick shifts. The xDrive all-wheel-drive system distributes power between the front and rear axles as needed, enhancing traction and stability.
Driving Characteristics
The 840i xDrive Steptronic delivers a refined and comfortable driving experience. The combination of the smooth inline-six engine and the 8-speed automatic transmission provides effortless acceleration. While not as overtly sporty as the M8, the 840i still offers engaging performance, with a 0-60 mph time of around 4.9 seconds. The xDrive all-wheel-drive system provides excellent grip in all weather conditions. The automatic transmission is well-tuned, offering both smooth automatic shifts and responsive manual control via steering wheel-mounted paddles. Compared to the 840i with a manual transmission, the Steptronic offers greater convenience and ease of use, particularly in city driving. The gear ratios are optimized for both acceleration and fuel efficiency, with a relatively tall final drive ratio contributing to improved highway cruising.
Equipment & Trim Levels
The 840i xDrive Steptronic came standard with a comprehensive list of features, including leather upholstery, power-adjustable seats with memory function, a premium sound system, a 12.3-inch digital instrument cluster, and a 10.25-inch central infotainment display with iDrive 7.0 operating system. Standard safety features included automatic emergency braking, lane departure warning, and adaptive cruise control. Optional extras included upgraded leather upholstery, a head-up display, a Bowers & Wilkins Diamond Surround Sound System, and various driver-assistance systems. Interior trim options included wood, aluminum, and carbon fiber accents. The convertible top was a fully automatic soft top, available in several colors.
Chassis & Braking
The 8 Series Convertible features a robust chassis designed for both comfort and handling. The front suspension utilizes a double wishbone design, while the rear suspension employs an independent multi-link setup. This configuration provides a good balance between ride comfort and handling precision. The 840i xDrive Steptronic is equipped with ventilated disc brakes on all four wheels. The braking system is enhanced by ABS (Anti-lock Braking System), electronic brake-force distribution, and brake assist. The steering system is an electric power-assisted rack-and-pinion system, providing precise and responsive steering feel.
Market Reception & Comparison
The BMW 8 Series Convertible (G14) 840i xDrive Steptronic was generally well-received by automotive critics. Reviewers praised its luxurious interior, comfortable ride, and refined performance. The combination of the inline-six engine and the automatic transmission was considered a good balance between power and usability. Compared to the higher-performance M8, the 840i was seen as a more comfortable and practical grand tourer. Fuel economy was respectable for a vehicle of its size and performance, with combined fuel consumption figures ranging from 29.4 to 30.5 US mpg. Reliability reports have been generally positive, with few major issues reported.
Legacy
The B58 engine has proven to be a reliable and durable powerplant, and the 840i xDrive Steptronic is expected to hold its value well in the used car market. The combination of luxury, performance, and technology makes it an attractive option for buyers seeking a high-end convertible. The G14 8 Series Convertible represents a return to form for BMW in the large luxury convertible segment, offering a compelling alternative to rivals such as the Mercedes-Benz S-Class Cabriolet and the Porsche 911 Cabriolet.
