The BMW 420i xDrive Steptronic, produced from 2017 to 2020, represents a key variant within the F32 generation of the 4 Series Coupe. Positioned as a mid-range offering, it blended respectable performance with all-weather capability thanks to BMW’s xDrive all-wheel-drive system and the convenience of an eight-speed automatic transmission. This model arrived with the facelift of the F32 series, bringing updated styling and technology to the popular coupe. It aimed to appeal to buyers seeking a premium driving experience without the higher price tag and performance focus of the 430i or M4 models.
Technical Specifications
| Brand | BMW |
| Model | 4 Series |
| Generation | 4 Series Coupe (F32, facelift 2017) |
| Type (Engine) | 420i (184 Hp) xDrive Steptronic |
| Start of production | 2017 |
| End of production | 2020 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Coupe |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption (urban) | 7.7-8.1 l/100 km (30.5 – 29 US mpg, 36.7 – 34.9 UK mpg, 13 – 12.3 km/l) |
| Fuel consumption (extra urban) | 4.8-5.1 l/100 km (49 – 46.1 US mpg, 58.9 – 55.4 UK mpg, 20.8 – 19.6 km/l) |
| Fuel consumption (combined) | 5.9-6.2 l/100 km (39.9 – 37.9 US mpg, 47.9 – 45.6 UK mpg, 16.9 – 16.1 km/l) |
| CO2 emissions | 137-144 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 7.8 sec |
| Acceleration 0 – 62 mph | 7.8 sec |
| Acceleration 0 – 60 mph | 7.4 sec |
| Maximum speed | 231 km/h (143.54 mph) |
| Emission standard | Euro 6 |
| Weight-to-power ratio | 8.5 kg/Hp, 117.2 Hp/tonne |
| Weight-to-torque ratio | 5.8 kg/Nm, 172 Nm/tonne |
| Power | 184 Hp @ 5000 rpm |
| Power per litre | 92.1 Hp/l |
| Torque | 270 Nm @ 1350-4600 rpm (199.14 lb.-ft. @ 1350-4600 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | B48B20A |
| 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 | 11:1 |
| 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 | 1570 kg (3461.26 lbs.) |
| Max. weight | 2090 kg (4607.66 lbs.) |
| Max load | 520 kg (1146.4 lbs.) |
| Trunk (boot) space – minimum | 445 l (15.72 cu. ft.) |
| Fuel tank capacity | 60 l (15.85 US gal | 13.2 UK gal) |
| Max. roof load | 75 kg (165.35 lbs.) |
| Permitted trailer load with brakes (12%) | 1700 kg (3747.86 lbs.) |
| Permitted trailer load without brakes | 750 kg (1653.47 lbs.) |
| Permitted towbar download | 75 kg (165.35 lbs.) |
| Length | 4640 mm (182.68 in.) |
| Width | 1825 mm (71.85 in.) |
| Height | 1392 mm (54.8 in.) |
| Wheelbase | 2810 mm (110.63 in.) |
| Front track | 1543 mm (60.75 in.) |
| Rear (Back) track | 1589 mm (62.56 in.) |
| Ride height (ground clearance) | 145 mm (5.71 in.) |
| Drag coefficient (Cd) | 0.30 |
| Minimum turning circle (turning diameter) | 11.8 m (38.71 ft.) |
| Drive wheel | All wheel drive (4×4) |
| 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 |
INTRODUCTION
The BMW 420i xDrive Steptronic, part of the F32 4 Series Coupe lineup (specifically the LCI or Life Cycle Impulse facelift introduced in 2017), offered a compelling blend of style, performance, and practicality. Built on the 1HX0/A3 platform shared with the 3 Series, the 4 Series Coupe distinguished itself with a more aggressively sloping roofline and a focus on driver engagement. The 420i xDrive variant aimed to provide a comfortable and capable all-weather driving experience, making it a popular choice in regions with inclement weather. This model bridged the gap between the more affordable 420i rear-wheel-drive version and the more powerful 430i and M4 options.
Powertrain & Engine Architecture
At the heart of the 420i xDrive Steptronic lies the B48B20A 2.0-liter inline-four cylinder engine. This engine is a member of BMW’s modular engine family, known for its efficiency and responsiveness. It utilizes direct fuel injection, a twin-scroll turbocharger, and variable valve timing (VANOS) and valve lift (Valvetronic) technologies to optimize power delivery and fuel economy. The engine produces 184 horsepower at 5000 rpm and 270 Nm (199 lb-ft) of torque between 1350 and 4600 rpm. This broad torque curve contributes to strong acceleration in everyday driving situations. The engine is longitudinally mounted, a traditional BMW layout, and paired with an eight-speed Steptronic automatic transmission. This transmission is known for its smooth shifts and quick response, and it features steering wheel-mounted paddle shifters for manual control. The xDrive all-wheel-drive system employs a multi-plate clutch to distribute torque between the front and rear axles, providing enhanced traction and stability.
Driving Characteristics
The 420i xDrive Steptronic delivers a refined and comfortable driving experience. While not as overtly sporty as the 430i or M4, it offers ample power for confident overtaking and highway cruising. The eight-speed automatic transmission is well-tuned, providing seamless gear changes and contributing to good fuel economy. The xDrive system provides excellent grip in a variety of conditions, inspiring confidence on wet or snowy roads. Compared to the rear-wheel-drive 420i, the xDrive version offers noticeably improved traction, particularly during acceleration. However, some drivers may perceive a slight increase in understeer due to the front-wheel involvement. The steering is precise and well-weighted, providing good feedback to the driver. The suspension strikes a good balance between comfort and handling, absorbing bumps and imperfections in the road while maintaining a relatively flat and controlled ride.
Equipment & Trim Levels
The 420i xDrive Steptronic came standard with a comprehensive list of features, including leatherette upholstery, automatic climate control, a 6.5-inch iDrive infotainment system with Bluetooth connectivity, and a suite of safety features such as ABS, stability control, and multiple airbags. Optional extras included leather upholstery, a larger iDrive screen with navigation, a premium sound system, a sunroof, and various driver-assistance systems like lane departure warning and adaptive cruise control. Trim levels varied depending on the market, but generally included options for upgraded interior trim materials and exterior styling elements.
Chassis & Braking
The 420i xDrive Steptronic utilizes a sophisticated chassis design. The front suspension features independent coil springs and struts, while the rear suspension employs an independent multi-link setup. This configuration provides a comfortable ride and precise handling. The braking system consists of ventilated discs on all four wheels, providing ample stopping power. ABS (Anti-lock Braking System) is standard, along with electronic brake-force distribution and brake assist. The xDrive system adds to the vehicle’s stability during braking, particularly on slippery surfaces.
Market Reception & Comparison
The 420i xDrive Steptronic was generally well-received by automotive critics. It was praised for its comfortable ride, refined interior, and capable all-wheel-drive system. However, some reviewers noted that the engine could feel slightly underpowered compared to the 430i. Fuel economy was considered to be good for a premium coupe, and the xDrive system was seen as a valuable asset in regions with harsh winters. Compared to the 430i, the 420i offered a more affordable entry point into the 4 Series lineup, but with a noticeable trade-off in performance. The 420i also offered a more practical and all-weather-capable alternative to the rear-wheel-drive 420i.
Legacy
The B48 engine family, including the B48B20A found in the 420i xDrive Steptronic, has proven to be relatively reliable. While some early examples experienced issues with oil leaks and timing chain wear, these problems were largely addressed with updated engine components. The eight-speed Steptronic transmission is also known for its durability. Today, the 420i xDrive Steptronic represents a good value on the used car market, offering a stylish and well-equipped coupe with all-wheel-drive capability. Its combination of comfort, practicality, and reasonable running costs makes it an appealing choice for buyers seeking a premium driving experience without breaking the bank.
