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 430i variant, powered by a 2.0-liter turbocharged inline-four engine producing 255 horsepower and incorporating mild hybrid technology, represents a key offering within the G23 lineup. Positioned as a mid-range option, it bridges the gap between the base 420i and the higher-performance M440i models, appealing to buyers seeking a balance of performance, luxury, and efficiency in a premium open-top experience. This generation of 4 Series convertibles builds upon the foundation laid by the F33 generation, offering enhanced refinement and modern features.
Technical Specifications
| Brand | BMW |
| Model | 4 Series |
| Generation | 4 Series Convertible (G23 LCI, facelift 2024) |
| Type (Engine) | 430i (255 Hp) Mild Hybrid Steptronic |
| Start of production | March, 2024 |
| Powertrain Architecture | MHEV (Mild Hybrid Electric Vehicle) |
| Body type | Cabriolet |
| Seats | 4 |
| Doors | 2 |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 60 mph | 6 sec |
| Maximum speed | 210 km/h (130.49 mph) |
| Weight-to-power ratio | 7.2 kg/Hp, 139.6 Hp/tonne |
| Weight-to-torque ratio | 4.6 kg/Nm, 219.1 Nm/tonne |
| Gross battery capacity | 0.4 kWh |
| Battery voltage | 48 V |
| Battery technology | Lithium-ion (Li-Ion) |
| Battery location | Under the front hood |
| Electric motor power | 11 Hp |
| Electric motor Torque | 25 Nm (18.44 lb.-ft.) |
| Electric motor location | Front, Longitudinal |
| Power | 255 Hp @ 4700-6500 rpm |
| Torque | 400 Nm (295.02 lb.-ft.) @ 1600-4500 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | B48B20O2 |
| Engine displacement | 1998 cm3 (121.93 cu. in.) |
| Number of cylinders | 4 |
| Engine configuration | Inline |
| Cylinder Bore | 82 mm (3.23 in.) |
| Piston Stroke | 94.6 mm (3.72 in.) |
| Compression ratio | 10.5:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Direct injection |
| Engine aspiration | Twin-power turbo, Intercooler |
| Valvetrain | Double-VANOS, VALVETRONIC |
| Kerb Weight | 1826 kg (4025.64 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) |
| Length | 4773 mm (187.91 in.) |
| Width | 1852 mm (72.91 in.) |
| Width including mirrors | 2081 mm (81.93 in.) |
| Height | 1387 mm (54.61 in.) |
| Wheelbase | 2851 mm (112.24 in.) |
| Front track | 1582 mm (62.28 in.) |
| Rear (Back) track | 1593 mm (62.72 in.) |
| Ride height (ground clearance) | 127 mm (5 in.) |
| Minimum turning circle (turning diameter) | 11.4 m (37.4 ft.) |
| Number of gears and type of gearbox | 8 gears, automatic transmission Steptronic |
| Front suspension | Spring Strut, Transverse stabilizer |
| Rear suspension | Independent multi-link spring suspension with stabilizer |
| 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 wheel tires | 225/45 R18; 225/40 R19 |
| Rear wheel tires | 225/45 R18; 225/40 R19; 255/35 R19 |
| Front wheel rims | 7.5J x 18; 8J x 19 |
| Rear wheel rims | 7.5J x 18; 8J x 19; 8.5J x 19 |
Powertrain & Engine Architecture
At the heart of the 430i Convertible lies the BMW B48B20O2 2.0-liter inline-four cylinder engine. This engine utilizes direct fuel injection and a twin-scroll turbocharger, along with BMW’s VALVETRONIC variable valve timing and Double-VANOS variable camshaft timing systems. These technologies work in concert to optimize engine efficiency and responsiveness across a wide range of driving conditions. The addition of 48V mild hybrid technology further enhances efficiency by allowing for features like extended coasting and smoother start-stop operation. The electric motor, integrated into the drivetrain, provides a small power boost during acceleration. The engine is paired with BMW’s eight-speed Steptronic automatic transmission, known for its smooth and quick shifts. This transmission is programmed for both comfort and performance, adapting to the driver’s style.
Driving Characteristics
The 430i Convertible delivers a refined and engaging driving experience. While not as overtly sporty as the M440i, the 255 horsepower and 295 lb-ft of torque provide ample power for both everyday driving and spirited excursions. The Steptronic transmission is well-matched to the engine, offering seamless gear changes and contributing to a relaxed cruising experience. The mild hybrid system provides a subtle but noticeable boost in responsiveness. Compared to earlier 4 Series convertibles, the G23 benefits from improved chassis rigidity and suspension tuning, resulting in more precise handling and reduced body roll. The rear-wheel drive configuration contributes to a balanced feel, although traction control is often engaged during aggressive acceleration. The gear ratios are tuned for a balance between acceleration and fuel economy, with eighth gear providing a comfortable overdrive for highway cruising.
Equipment & Trim Levels
The 430i Convertible comes standard with a comprehensive suite of features, including BMW’s iDrive infotainment system with a touchscreen display, navigation, Apple CarPlay and Android Auto compatibility, and a premium sound system. Standard interior appointments include leatherette upholstery, power-adjustable front seats, and automatic climate control. Optional extras include genuine leather upholstery, heated and ventilated front seats, a head-up display, and a variety of driver-assistance systems such as adaptive cruise control and lane-keeping assist. The LCI facelift brought updated interior trim options and enhanced digital features. Exterior options include a range of wheel designs, paint colors, and soft-top fabric choices.
Chassis & Braking
The G23 4 Series Convertible utilizes a sophisticated chassis design featuring a multi-link rear suspension and a front suspension with a spring strut setup. The suspension is tuned to provide a balance between comfort and handling. The steering system is an electric power-assisted rack-and-pinion system, offering precise and responsive steering feel. Braking duties are handled by ventilated disc brakes on all four wheels, providing ample stopping power. The standard safety features include ABS, stability control, and a suite of airbags. The chassis is designed to minimize weight while maximizing rigidity, contributing to improved handling and crash safety.
Market Reception & Comparison
The 430i Convertible has been generally well-received by automotive critics, praised for its refined driving experience, stylish design, and comfortable interior. Compared to the base 420i, the 430i offers a significant performance upgrade, while remaining more affordable than the M440i. Fuel economy is respectable for a premium convertible, with EPA estimates typically in the mid-20s mpg combined. Reliability has been generally good, although some owners have reported minor issues with the infotainment system. Compared to competitors such as the Audi A5 Cabriolet and Mercedes-Benz C-Class Cabriolet, the 430i offers a more engaging driving experience and a more modern interior.
Legacy
The B48 engine family, including the B48B20O2 found in the 430i, has proven to be a reliable and durable powertrain. While long-term reliability data for the G23 generation is still emerging, the B48 engine has a good track record in other BMW models. The mild hybrid technology introduced with the LCI facelift is expected to further enhance the engine’s efficiency and longevity. On the used car market, the 430i Convertible is expected to hold its value well, appealing to buyers seeking a premium open-top experience with a balance of performance, luxury, and technology. The G23 LCI represents a significant evolution of the 4 Series Convertible, building upon the strengths of its predecessor and offering a compelling package for discerning drivers.
