The BMW 8 Series Convertible (G14 LCI), specifically the 840d xDrive Steptronic model, represents a mid-cycle refresh of the G14 generation, introduced in March 2022. This variant positions itself as a grand touring luxury vehicle, blending performance with open-top motoring. The “LCI” (Life Cycle Impulse) facelift brought styling updates and technological enhancements to the 8 Series range, while the 840d trim offered a diesel-powered alternative within the lineup, appealing to buyers prioritizing fuel efficiency and strong torque delivery. It sits in the mid-range of the 8 Series Convertible offerings, below the higher-performance M8 Competition but above the entry-level 840i.
Technical Specifications
| Brand | BMW |
| Model | 8 Series |
| Generation | 8 Series Convertible (G14 LCI, facelift 2022) |
| Type (Engine) | 840d (340 Hp) Mild Hybrid xDrive Steptronic |
| Start of production | March, 2022 |
| Powertrain Architecture | MHEV (Mild Hybrid Electric Vehicle) |
| Body type | Cabriolet |
| Seats | 4 |
| Doors | 2 |
| Combined fuel consumption (WLTP) | 6.7-7 l/100 km (35.1 – 33.6 US mpg, 42.2 – 40.4 UK mpg, 14.9 – 14.3 km/l) |
| CO2 emissions (WLTP) | 175-183 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 5.1 sec |
| Acceleration 0 – 62 mph | 5.1 sec |
| Acceleration 0 – 60 mph | 4.8 sec |
| Maximum speed | 250 km/h (155.34 mph), Electronically limited |
| Emission standard | Euro 6d |
| Weight-to-power ratio | 6 kg/Hp, 167.9 Hp/tonne |
| Weight-to-torque ratio | 2.9 kg/Nm, 345.7 Nm/tonne |
| Battery voltage | 48 V |
| Battery technology | Lithium-ion (Li-Ion) |
| Battery location | Under the front hood |
| Electric motor power | 11 Hp |
| Electric motor location | Front, Longitudinal |
| Power | 340 Hp @ 4400 rpm |
| Torque | 700 Nm @ 1750-2250 rpm (516.29 lb.-ft. @ 1750-2250 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | B57D30B |
| Engine displacement | 2993 cm3 (182.64 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 84 mm (3.31 in.) |
| Piston Stroke | 90 mm (3.54 in.) |
| Compression ratio | 16.5:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Twin-power turbo, Intercooler |
| Valvetrain | DOHC |
| Engine oil capacity | 7 l (7.4 US qt | 6.16 UK qt) |
| Kerb Weight | 2025 kg (4464.36 lbs.) |
| Max. weight | 2500 kg (5511.56 lbs.) |
| Max load | 475 kg (1047.2 lbs.) |
| Trunk (boot) space – minimum | 280 l (9.89 cu. ft.) |
| Trunk (boot) space – maximum | 350 l (12.36 cu. ft.) |
| Fuel tank capacity | 66 l (17.44 US gal | 14.52 UK gal) |
| AdBlue tank | 18.5 l (4.89 US gal | 4.07 UK gal) |
| Length | 4851 mm (190.98 in.) |
| Width | 1902 mm (74.88 in.) |
| Width including mirrors | 2137 mm (84.13 in.) |
| Height | 1345 mm (52.95 in.) |
| Wheelbase | 2822 mm (111.1 in.) |
| Front track | 1627 mm (64.06 in.) |
| Rear (Back) track | 1642 mm (64.65 in.) |
| Front overhang | 953 mm (37.52 in.) |
| Rear overhang | 1076 mm (42.36 in.) |
| Ride height (ground clearance) | 118 mm (4.65 in.) |
| Drag coefficient (Cd) | 0.30 |
| Minimum turning circle | 11.9 m (39.04 ft.) |
| Drivetrain Architecture | ICE and electric motor drive all four wheels, mixed mode operation |
| Drive wheel | 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 |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Electric Steering |
| Front tires | 245/40 R19; 245/35 R20 |
| Rear tires | 275/35 R19; 275/30 R20 |
| Front wheel rims | 8J x 19; 8J x 20 |
| Rear wheel rims | 9J x 19; 9J x 20 |
Powertrain & Engine Architecture
The heart of the 840d xDrive is BMW’s B57D30B 3.0-liter inline-six diesel engine. This engine is a member of the modular BMW engine family and benefits from extensive development over the years. It utilizes a sophisticated diesel commonrail fuel injection system, delivering precise fuel metering for optimal combustion. The engine employs a twin-turbocharger setup – one low-inertia turbocharger for immediate response and a larger turbocharger for peak power. An intercooler further enhances performance by cooling the intake air. The B57 engine also features a 48V mild hybrid system, incorporating a starter-generator that provides a power boost during acceleration and enables smoother start-stop operation. This mild hybridization contributes to improved fuel efficiency. The engine is paired with BMW’s 8-speed Steptronic automatic transmission, known for its smooth and quick shifts. The transmission is specifically tuned to complement the diesel engine’s torque characteristics, providing seamless power delivery.
Driving Characteristics
The 840d xDrive offers a distinctly different driving experience compared to its gasoline-powered siblings. While lacking the outright acceleration of the 840i, the 840d compensates with a substantial 700 Nm (516 lb-ft) of torque available from just 1750 rpm. This results in effortless acceleration and strong in-gear performance, making it ideal for long-distance cruising and overtaking. The 8-speed automatic transmission is well-matched to the engine, providing smooth and timely gear changes. The xDrive all-wheel-drive system ensures excellent traction in all weather conditions. Compared to manual transmission versions (not typically offered on this trim), the automatic provides a more relaxed and convenient driving experience. The mild hybrid system contributes to a refined and responsive feel, particularly during initial acceleration.
Equipment & Trim Levels
The 840d xDrive Convertible came standard with a comprehensive array of luxury features. These included leather upholstery, power-adjustable seats with memory function, a premium sound system, a large infotainment display with iDrive controller, and a head-up display. Standard safety features included automatic emergency braking, lane departure warning, and adaptive cruise control. Optional extras included upgraded leather options, individual interior trim choices, a Bowers & Wilkins Diamond Surround Sound System, and various driver assistance systems like Parking Assistant Plus. The overall interior ambiance focused on providing a luxurious and comfortable experience for both the driver and passengers.
Chassis & Braking
The 8 Series Convertible utilizes a sophisticated chassis design. The front suspension features a double wishbone setup, while the rear employs an independent multi-link suspension. This configuration provides a balance between ride comfort and handling precision. The 840d xDrive is equipped with ventilated disc brakes on all four wheels, providing ample stopping power. The braking system is further 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 suspension setup provides a comfortable ride, while optional adaptive suspension systems were available to further tailor the ride characteristics to the driver’s preferences.
Market Reception & Comparison
The 840d xDrive Convertible was generally well-received by automotive critics. It was praised for its refined driving experience, strong performance, and excellent fuel economy. Compared to the 840i, the 840d offered superior fuel efficiency and torque, making it a more practical choice for long-distance travel. However, some critics noted that the diesel engine lacked the responsiveness and sound of the gasoline engine. In terms of reliability, the B57 engine has proven to be robust and durable, with relatively few reported issues. Fuel economy figures consistently demonstrated the 840d’s advantage over its gasoline counterpart.
Legacy
The BMW 840d xDrive Convertible (G14 LCI) represents a compelling blend of luxury, performance, and efficiency. The B57 engine has established itself as a reliable and capable powerplant within the BMW lineup. On the used car market, these models are sought after by buyers looking for a grand touring convertible with strong torque and good fuel economy. The mild hybrid technology adds a layer of modernity and refinement. While not as common as the 840i, the 840d offers a unique and appealing alternative for discerning buyers.
