The BMW 4 Series Convertible (F33), specifically the 430i variant with the Steptronic automatic transmission, represents a compelling blend of performance and open-air driving enjoyment. Produced from 2017 to 2020 as part of the F33 lifecycle facelift, this model occupied a significant position in BMW’s lineup, offering a step up in power and refinement from the base 420i while remaining more accessible than the range-topping M4. It was designed to appeal to buyers seeking a sporty yet comfortable convertible experience, balancing dynamic handling with everyday usability. The F33 generation, built on the BMW 3 Series (F30) platform, aimed to deliver a more sophisticated and stylish alternative to traditional hardtop coupes.
Technical Specifications
| Brand | BMW |
| Model | 4 Series |
| Generation | 4 Series Convertible (F33, facelift 2017) |
| Type (Engine) | 430i (252 Hp) Steptronic |
| Start of production | 2017 |
| End of production | 2020 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Cabriolet |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption (urban) | 7.5-7.9 l/100 km (31.4 – 29.8 US mpg, 37.7 – 35.8 UK mpg, 13.3 – 12.7 km/l) |
| Fuel consumption (extra urban) | 5.0-5.3 l/100 km (47 – 44.4 US mpg, 56.5 – 53.3 UK mpg, 20 – 18.9 km/l) |
| Fuel consumption (combined) | 5.9-6.3 l/100 km (39.9 – 37.3 US mpg, 47.9 – 44.8 UK mpg, 16.9 – 15.9 km/l) |
| CO2 emissions | 138-146 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 6.3 sec |
| Acceleration 0 – 62 mph | 6.3 sec |
| Acceleration 0 – 60 mph | 6 sec (Calculated) |
| Maximum speed | 250 km/h (155.34 mph) |
| Emission standard | Euro 6 |
| Weight-to-power ratio | 6.9 kg/Hp, 145.2 Hp/tonne |
| Weight-to-torque ratio | 5 kg/Nm, 201.7 Nm/tonne |
| Power | 252 Hp @ 5200 rpm |
| Power per litre | 126.1 Hp/l |
| Torque | 350 Nm @ 1450-4800 rpm (258.15 lb.-ft. @ 1450-4800 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | B48B20B |
| 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 | 10.2:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Direct injection |
| Engine aspiration | Twin-power turbo, Intercooler |
| Engine oil capacity | 5.25 l (5.55 US qt | 4.62 UK qt) |
| Coolant | 8.1 l (8.56 US qt | 7.13 UK qt) |
| Kerb Weight | 1735 kg (3825.02 lbs.) |
| Max. weight | 2195 kg (4839.15 lbs.) |
| Max load | 460 kg (1014.13 lbs.) |
| Trunk (boot) space – minimum | 370 l (13.07 cu. ft.) |
| Fuel tank capacity | 60 l (15.85 US gal | 13.2 UK gal) |
| Permitted trailer load with brakes (12%) | 1600 kg (3527.4 lbs.) |
| Permitted trailer load without brakes | 745 kg (1642.44 lbs.) |
| Permitted towbar download | 75 kg (165.35 lbs.) |
| Length | 4640 mm (182.68 in.) |
| Width | 1825 mm (71.85 in.) |
| Height | 1384 mm (54.49 in.) |
| Wheelbase | 2810 mm (110.63 in.) |
| Front track | 1544 mm (60.79 in.) |
| Rear (Back) track | 1593 mm (62.72 in.) |
| Ride height (ground clearance) | 130 mm (5.12 in.) |
| Drag coefficient (Cd) | 0.30 |
| Minimum turning circle | 11.3 m (37.07 ft.) |
| Drivetrain Architecture | Rear wheel drive |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 8 gears, automatic transmission Steptronic |
| Front suspension | Independent coil spring |
| 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 | 225/50 R17; 225/45 R18; 255/40 R18; 225/40 R19; 255/35 R19 |
| Wheel rims size | 7.5J x 17; 8J x 18; 8.5J x 18; 8J x 19; 8.5J x 19 |
Powertrain & Engine Architecture
The 430i Convertible is powered by BMW’s B48B20B 2.0-liter turbocharged inline-four engine. This engine is a cornerstone of BMW’s modern powertrain strategy, featuring direct fuel injection, a twin-scroll turbocharger, and variable valve timing (VANOS) and valve lift (Valvetronic) technologies. These technologies work in concert to optimize both power delivery and fuel efficiency. The B48 engine produces 252 horsepower at 5200 rpm and 350 Nm (258 lb-ft) of torque between 1450 and 4800 rpm. The Steptronic 8-speed automatic transmission is a crucial component, offering smooth and responsive gear changes. It features adaptive shift programs that adjust to the driver’s style and driving conditions. The transmission’s wide gear ratio spread contributes to both acceleration and fuel economy.
Driving Characteristics
The 430i Convertible with the Steptronic transmission delivers a refined and engaging driving experience. While not as overtly sporty as the M4, it provides ample power for spirited driving. The 0-60 mph sprint takes approximately 6 seconds, and the car feels responsive in everyday driving situations. The Steptronic transmission is well-tuned, providing quick and seamless shifts. In Sport mode, the transmission holds gears longer and downshifts more aggressively, enhancing the driving experience. Compared to the 420i, the 430i offers a noticeable increase in performance, while the manual transmission variants provide a more direct connection to the engine. However, the automatic transmission offers convenience and ease of use, particularly in urban environments.
Equipment & Trim Levels
The 430i Convertible typically came well-equipped as standard. Features included leather upholstery, power-adjustable seats, a premium sound system, and BMW’s iDrive infotainment system with a central display screen. Common options included navigation, heated seats, a head-up display, and various driver-assistance systems such as lane departure warning and collision mitigation. Interior trim options ranged from wood veneers to aluminum accents, allowing buyers to personalize the cabin. The convertible top was a fully automatic fabric soft top, available in several colors, and could be raised or lowered in around 20 seconds at speeds up to 30 mph.
Chassis & Braking
The F33 4 Series Convertible utilizes a sophisticated chassis design, featuring an independent suspension at all four corners. The front suspension employs coil springs and struts, while the rear utilizes a multi-link setup. This configuration provides a good balance between ride comfort and handling precision. The 430i typically came equipped with ventilated disc brakes on all four wheels, providing ample stopping power. ABS, dynamic stability control (DSC), and traction control were standard safety features. The steering system is an electric power-assisted rack-and-pinion setup, offering precise and responsive steering feel.
Market Reception & Comparison
The 430i Convertible was generally well-received by automotive critics. It was praised for its stylish design, comfortable interior, and engaging driving dynamics. The 2.0-liter turbocharged engine was considered a good compromise between performance and fuel efficiency. Compared to the 420i, the 430i offered a significant performance upgrade, making it a more appealing option for drivers who prioritized power. However, some critics noted that the 430i lacked the outright performance of the M4. Fuel economy figures were respectable, averaging around 39.9 mpg in combined driving. Reliability reports have been generally positive, with the B48 engine proving to be a robust and dependable unit.
Legacy
The BMW 430i Convertible (F33) remains a desirable used car option. The B48 engine has proven to be relatively reliable, and parts availability is good. The car’s stylish design and engaging driving dynamics continue to appeal to buyers seeking a premium convertible experience. While maintenance costs can be higher than those of more mainstream brands, the 430i offers a compelling blend of performance, luxury, and open-air enjoyment. Its position as a well-rounded and refined convertible ensures its continued popularity in the used car market.
