The BMW 8 Series Convertible (G14) 840i xDrive Steptronic represents BMW’s foray back into the large, luxury convertible market, launched in July 2019 and continuing through 2020. Positioned as a mid-range offering within the G14 8 Series Convertible lineup, it slots between the base 840i and the high-performance M850i. This variant aimed to provide a balance of performance, luxury, and all-weather capability through BMW’s xDrive all-wheel-drive system. The G14 builds upon the success of the 8 Series coupe (G15), offering open-air driving enjoyment with the same sophisticated engineering and premium appointments.
Technical Specifications
| Brand | BMW |
| Model | 8 Series |
| Generation | 8 Series Convertible (G14) |
| Type (Engine) | 840i (340 Hp) xDrive Steptronic |
| Start of production | July, 2019 |
| End of production | 2020 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Cabriolet |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption (economy) – urban (NEDC) | 9.6-9.8 l/100 km (24.5 – 24 US mpg, 29.4 – 28.8 UK mpg, 10.4 – 10.2 km/l) |
| Fuel consumption (economy) – extra urban (NEDC) | 6.4-6.7 l/100 km (36.8 – 35.1 US mpg, 44.1 – 42.2 UK mpg, 15.6 – 14.9 km/l) |
| Fuel consumption (economy) – combined (NEDC) | 7.6-7.8 l/100 km (30.9 – 30.2 US mpg, 37.2 – 36.2 UK mpg, 13.2 – 12.8 km/l) |
| CO2 emissions (NEDC) | 173-178 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 4.9 sec |
| Acceleration 0 – 62 mph | 4.9 sec |
| Acceleration 0 – 60 mph | 4.7 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Emission standard | Euro 6d – TEMP |
| Weight-to-power ratio | 5.5 kg/Hp, 180.9 Hp/tonne |
| Weight-to-torque ratio | 3.8 kg/Nm, 266 Nm/tonne |
| Power | 340 Hp @ 5000-6500 rpm |
| Power per litre | 113.4 Hp/l |
| Torque | 500 Nm @ 1600-4500 rpm (368.78 lb.-ft. @ 1600-4500 rpm) |
| 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 |
| Engine oil capacity | 6.5 l (6.87 US qt | 5.72 UK qt) |
| Kerb Weight | 1880 kg (4144.69 lbs.) |
| Max. weight | 2400 kg (5291.09 lbs.) |
| Max load | 520 kg (1146.4 lbs.) |
| Trunk (boot) space – minimum | 280 l (9.89 cu. ft.) |
| Trunk (boot) space – maximum | 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.) |
| Width including mirrors | 2137 mm (84.13 in.) |
| Height | 1339 mm (52.72 in.) |
| Wheelbase | 2822 mm (111.1 in.) |
| Front track | 1627 mm (64.06 in.) |
| Rear (Back) track | 1642 mm (64.65 in.) |
| Ride height (ground clearance) | 118 mm (4.65 in.) |
| Drag coefficient (Cd) | 0.31 |
| Minimum turning circle (turning diameter) | 11.9 m (39.04 ft.) |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels permanently, and the front wheels are driven through an electrically or mechanically operated clutch if necessary. |
| Drive wheel | All wheel drive (4×4) |
| 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 100Y XL; 275/40 R18 103Y XL |
| Wheel rims size | 8J x 18; 9J x 18 |
Powertrain & Engine Architecture
The 840i xDrive Steptronic is powered by 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. It utilizes a single twin-scroll turbocharger, direct fuel injection, and Double-VANOS variable valve timing for both intake and exhaust. The B58 engine produces 340 horsepower at 5,000-6,500 rpm and 500 Nm (368 lb-ft) of torque between 1,600 and 4,500 rpm. The engine is longitudinally mounted at the front of the vehicle. The transmission is an 8-speed Steptronic automatic, known for its quick and smooth shifts. This transmission features a torque converter and allows for both automatic and manual gear selection via steering wheel-mounted paddles. The xDrive all-wheel-drive system is a sophisticated system that normally sends power to the rear wheels, but can dynamically distribute torque to the front wheels when traction is needed.
Driving Characteristics
The 840i xDrive Steptronic offers a refined and capable driving experience. The 3.0-liter inline-six provides ample power for both spirited driving and comfortable cruising. Acceleration from 0-60 mph takes approximately 4.7 seconds. The 8-speed automatic transmission is well-tuned, providing seamless gear changes and contributing to the car’s overall smoothness. The xDrive system enhances stability and traction, particularly in adverse weather conditions. Compared to the higher-performance M850i, the 840i offers a more relaxed driving experience, prioritizing comfort over outright speed. While the M850i’s V8 delivers more aggressive acceleration, the 840i’s inline-six provides a more linear and predictable power delivery. The gear ratios are optimized for both acceleration and fuel efficiency, with a relatively tall final drive ratio contributing to improved highway economy.
Equipment & Trim Levels
The 840i xDrive Steptronic came standard with a high level of equipment, befitting its luxury positioning. Standard features included leather upholstery, power-adjustable seats with memory function, a premium sound system, a large infotainment screen with iDrive controller, navigation, and a suite of driver-assistance systems such as lane departure warning and automatic emergency braking. Optional extras included upgraded leather options, a head-up display, active roll stabilization, and various cosmetic enhancements. The interior design emphasized luxury and craftsmanship, with high-quality materials and meticulous attention to detail. Dashboard configuration was modern and driver-focused, with a digital instrument cluster and a central infotainment screen.
Chassis & Braking
The 8 Series Convertible utilizes a sophisticated chassis design to deliver a balance of comfort and handling. The front suspension features a double-wishbone setup, while the rear suspension employs an independent multi-link design. This configuration provides excellent wheel control and ride quality. 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) and electronic brake-force distribution. The car’s weight distribution is carefully optimized to enhance handling balance. The standard tire size is 245/45 R18 at the front and 275/40 R18 at the rear, providing good grip and stability.
Market Reception & Comparison
The BMW 8 Series Convertible (G14) 840i xDrive Steptronic was generally well-received by automotive critics. Reviewers praised its luxurious interior, refined driving experience, and capable all-wheel-drive system. The 3.0-liter inline-six engine was lauded for its smooth power delivery and efficiency. Compared to the M850i, the 840i was seen as a more sensible choice for buyers who prioritized comfort and everyday usability over outright performance. Fuel economy was respectable for a vehicle of its size and performance, with combined fuel consumption figures ranging from 7.6 to 7.8 l/100 km (30.9 – 30.2 US mpg). Reliability reports have been generally positive, with few major issues reported.
Legacy
The B58 engine powering the 840i has proven to be a robust and reliable powerplant. The 8-speed Steptronic automatic transmission is also known for its durability. On the used car market, the G14 840i xDrive Steptronic holds its value well, reflecting its desirable combination of luxury, performance, and all-weather capability. These vehicles are sought after by buyers who appreciate a refined and sophisticated driving experience. Regular maintenance, including oil changes and fluid checks, is essential to ensure the long-term reliability of this powertrain. The G14 840i represents a significant step forward in BMW’s convertible offerings, combining modern technology with classic BMW driving dynamics.
