The BMW 4 Series Convertible (G23) received a Life Cycle Impulse (LCI), or facelift, in March 2024, bringing updates to its styling, technology, and powertrain options. The M440i xDrive Steptronic variant, powered by a 3.0-liter inline-six engine with mild hybrid technology, represents a performance-oriented offering within the G23 lineup. This model year spans production from 2024 through 2025, building upon the foundation of the G23 platform introduced in 2020, which shares its underpinnings with the 3 Series sedan (G20). The M440i sits at the top of the non-M performance range for the 4 Series Convertible, offering a blend of luxury, performance, and open-air driving enjoyment.
Technical Specifications
| Brand | BMW |
| Model | 4 Series |
| Generation | 4 Series Convertible (G23 LCI, facelift 2024) |
| Type (Engine) | M440i (374 Hp) Mild Hybrid xDrive Steptronic |
| Start of production | March, 2024 |
| End of production | 2025 |
| Powertrain Architecture | MHEV (Mild Hybrid Electric Vehicle) |
| Body type | Cabriolet |
| Seats | 4 |
| Doors | 2 |
| Combined fuel consumption (WLTP) | 8.1-8.7 l/100 km (29 – 27 US mpg) |
| CO2 emissions (WLTP) | 182-197 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 6e |
| Weight-to-power ratio | 5.1 kg/Hp |
| Weight-to-torque ratio | 3.8 kg/Nm |
| Gross battery capacity | 0.4 kWh |
| Battery voltage | 48 V |
| Battery technology | Lithium-ion (Li-Ion) |
| Electric motor power | 11 Hp |
| Electric motor Torque | 25 Nm (18.44 lb.-ft.) |
| Power | 374 Hp @ 5500-6500 rpm |
| Torque | 500 Nm @ 1900-5000 rpm (368.78 lb.-ft. @ 1900-5000 rpm) |
| Engine displacement | 2998 cm3 (182.95 cu. in.) |
| Number of cylinders | 6 |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | B58B30M2 |
| Cylinder Bore | 82 mm (3.23 in.) |
| Piston Stroke | 94.6 mm (3.72 in.) |
| Compression ratio | 10.2:1 |
| Engine oil capacity | 7.2 l (7.61 US qt | 6.34 UK qt) |
| Kerb Weight | 1890 kg (4166.74 lbs.) |
| Max. weight | 2375 kg (5235.98 lbs.) |
| Max load | 485 kg (1069.24 lbs.) |
| Trunk (boot) space – minimum | 300 l (10.59 cu. ft.) |
| Trunk (boot) space – maximum | 385 l (13.6 cu. ft.) |
| Fuel tank capacity | 59 l (15.59 US gal | 12.98 UK gal) |
| Permitted trailer load with brakes (12%) | 1800 kg (3968.32 lbs.) |
| Permitted trailer load without brakes | 750 kg (1653.47 lbs.) |
| Length | 4770 mm (187.8 in.) |
| Width | 1852 mm (72.91 in.) |
| Width including mirrors | 2081 mm (81.93 in.) |
| Height | 1394 mm (54.88 in.) |
| Wheelbase | 2851 mm (112.24 in.) |
| Front track | 1583 mm (62.32 in.) |
| Rear track | 1592 mm (62.68 in.) |
| Ride height (ground clearance) | 126 mm (4.96 in.) |
| Drag coefficient (Cd) | 0.28 |
| Minimum turning circle | 12 m (39.37 ft.) |
| Number of gears | 8 |
| Gearbox type | Automatic transmission Steptronic |
Powertrain & Engine Architecture
The heart of the 2024 BMW 4 Series Convertible M440i is the B58B30M2 3.0-liter inline-six engine. This engine is a member of the BMW B58 family, known for its smooth power delivery and efficiency. It utilizes direct fuel injection, a twin-scroll turbocharger with intercooling, and BMW’s VALVETRONIC and Double-VANOS variable valve timing systems. The addition of a 48V mild hybrid system enhances efficiency and provides a small power boost. The electric motor, producing 11 horsepower and 25 Nm (18.44 lb-ft) of torque, assists during acceleration and allows for a smoother start-stop function. The engine is longitudinally mounted at the front of the vehicle and paired with an 8-speed Steptronic automatic transmission. This transmission is known for its quick and precise shifts, contributing to the car’s overall performance.
Driving Characteristics
The M440i xDrive Steptronic delivers a refined and engaging driving experience. The 374 hp and 500 Nm (368.78 lb-ft) of torque provide strong acceleration, with a 0-60 mph time of around 4.7 seconds. The 8-speed automatic transmission is well-tuned, offering smooth gear changes and responsive performance. The xDrive all-wheel-drive system provides excellent traction in various conditions. Compared to lower-powered 4 Series variants, such as the 430i, the M440i offers a significantly more potent driving experience. While not as track-focused as a dedicated M car, the M440i provides ample power for spirited driving and comfortable cruising. The mild hybrid system contributes to improved fuel economy and a more refined start-stop experience.
Equipment & Trim Levels
The M440i trim level comes standard with a comprehensive list of features, including premium leather upholstery, a 12.3-inch digital instrument cluster, a 14.9-inch central infotainment display with iDrive 8 operating system, and a premium sound system. Standard safety features include automatic emergency braking, lane departure warning, and adaptive cruise control. Optional extras include a head-up display, ventilated front seats, and a variety of interior trim options. The LCI facelift brought updated interior trim options and enhanced connectivity features.
Chassis & Braking
The G23 4 Series Convertible utilizes a sophisticated chassis design. The front suspension features spring struts with a transverse stabilizer, while the rear suspension employs an independent multi-link setup, also with a stabilizer bar. This configuration provides a good balance between comfort and handling. The M440i is equipped with ventilated disc brakes on all four wheels, providing ample stopping power. The steering system is an electric power-assisted rack and pinion system, offering precise and responsive steering feel. The standard tire size is 225/45 R18 at the front and 255/40 R18 at the rear.
Market Reception & Comparison
The 2024 BMW 4 Series Convertible M440i xDrive Steptronic has been well-received by automotive critics. Reviewers praise its powerful engine, refined driving dynamics, and luxurious interior. Compared to other premium convertible options, such as the Audi A5 Cabriolet and Mercedes-Benz C-Class Cabriolet, the 4 Series Convertible stands out for its sporty handling and engaging driving experience. Fuel economy is respectable for a performance-oriented convertible, with combined fuel consumption ranging from 8.1 to 8.7 l/100 km. Reliability is generally good, although some owners have reported minor issues with the infotainment system.
Legacy
The B58 engine family has proven to be highly reliable, and the mild hybrid system is expected to further enhance its longevity. The G23 4 Series Convertible, particularly the M440i variant, is expected to hold its value well in the used car market. Its combination of performance, luxury, and open-air driving enjoyment makes it a desirable option for enthusiasts. As technology continues to evolve, the G23 LCI will be remembered as a refined and capable grand tourer that offered a compelling blend of performance and comfort.
