The BMW 4 Series Coupe (F32) 420i Steptronic, produced primarily during the 2016 model year, represented an entry point into the F32 4 Series lineup. Positioned below the 430i and 440i models, the 420i offered a balance of BMW’s sporty driving dynamics with improved fuel efficiency and a more accessible price point. It was marketed towards buyers seeking a premium coupe experience without the higher running costs associated with the more powerful engines. The F32 generation, launched in 2013, was BMW’s replacement for the 3 Series Coupe, establishing the 4 Series as a distinct model range emphasizing style and driving pleasure.
Technical Specifications
| Brand | BMW |
| Model | 4 Series |
| Generation | 4 Series Coupe (F32) |
| Type (Engine) | 420i (184 Hp) Steptronic |
| Start of production | 2016 |
| End of production | 2016 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Coupe |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption (urban) | 7.1-7.6 l/100 km (33.1 – 30.9 US mpg) |
| Fuel consumption (extra urban) | 4.5-4.7 l/100 km (52.3 – 50 US mpg) |
| Fuel consumption (combined) | 5.5-5.8 l/100 km (42.8 – 40.6 US mpg) |
| CO2 emissions | 127-134 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 7.5 sec |
| Acceleration 0 – 62 mph | 7.5 sec |
| Acceleration 0 – 60 mph | 7.1 sec |
| Maximum speed | 236 km/h (146.64 mph) |
| Emission standard | Euro 6 |
| Weight-to-power ratio | 8.1 kg/Hp |
| Weight-to-torque ratio | 5.5 kg/Nm |
| Power | 184 Hp @ 5000 rpm |
| 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 | 5.3 l (5.6 US qt | 4.66 UK qt) |
| Coolant | 7.8 l (8.24 US qt | 6.86 UK qt) |
| Kerb Weight | 1495 kg (3295.91 lbs.) |
| Max. weight | 2015 kg (4442.31 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%) | 1500 kg (3306.93 lbs.) |
| Permitted trailer load without brakes | 695 kg (1532.21 lbs.) |
| Permitted towbar download | 75 kg (165.35 lbs.) |
| Length | 4638 mm (182.6 in.) |
| Width | 1825 mm (71.85 in.) |
| Height | 1377 mm (54.21 in.) |
| Wheelbase | 2810 mm (110.63 in.) |
| Front track | 1545 mm (60.83 in.) |
| Rear (Back) track | 1594 mm (62.76 in.) |
| Ride height (ground clearance) | 130 mm (5.12 in.) |
| Drag coefficient (Cd) | 0.29 |
| Minimum turning circle (turning diameter) | 11.3 m (37.07 ft.) |
| Drivetrain Architecture | 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 94W; 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 420i Steptronic was powered by the BMW B48B20A 2.0-liter inline-four cylinder engine. This engine is a member of BMW’s modular engine family, utilizing a single turbocharger with twin-scroll technology. Direct fuel injection, operating at a pressure of 200 bar, ensures precise fuel delivery for optimal combustion. The engine produces 184 horsepower at 5,000 rpm and 270 Nm (199 lb-ft) of torque between 1,350 and 4,600 rpm. The B48 engine features a Valvetronic system, which allows for stepless control of valve lift, optimizing engine efficiency and responsiveness. The “Steptronic” transmission refers to BMW’s 8-speed automatic transmission, known for its smooth shifts and efficiency. This transmission features a torque converter and allows for both automatic and manual gear selection via steering wheel-mounted paddles or the gear selector.
Driving Characteristics
The 420i Steptronic offered a comfortable and refined driving experience. While not as overtly sporty as the 430i or 440i, the 2.0-liter engine provided adequate power for everyday driving and occasional spirited runs. The 8-speed automatic transmission was well-matched to the engine’s torque curve, providing smooth and timely gear changes. Acceleration from 0 to 60 mph took approximately 7.1 seconds. Compared to the 6-speed manual version of the 420i, the Steptronic offered slightly slower acceleration due to the transmission’s inherent efficiency losses, but it prioritized ease of use and comfort. The rear-wheel-drive configuration contributed to the car’s balanced handling, although it lacked the outright grip of all-wheel-drive models.
Equipment & Trim Levels
The 420i Steptronic came standard with a respectable level of equipment. Standard features typically included leatherette upholstery, automatic climate control, a 6.5-inch iDrive infotainment system with Bluetooth connectivity, and power-adjustable front seats. Optional extras included a larger iDrive screen, navigation system, premium sound system, heated seats, and a sunroof. Trim levels were relatively simple, with most customization options available as individual add-ons. The interior design was typical BMW, with a driver-focused layout and high-quality materials.
Chassis & Braking
The F32 4 Series featured a sophisticated chassis design. The front suspension utilized independent coil springs and struts, while the rear suspension employed an independent multi-link setup. This configuration provided a good balance of ride comfort and handling precision. The 420i Steptronic typically came equipped with ventilated disc brakes on all four wheels, providing ample stopping power. Anti-lock Braking System (ABS) and Electronic Stability Control (ESC) were standard safety features. The car’s weight distribution was close to 50/50, contributing to its balanced handling characteristics.
Market Reception & Comparison
The 420i Steptronic was generally well-received by automotive critics. It was praised for its fuel efficiency, comfortable ride, and refined interior. However, some reviewers noted that the engine lacked the outright punch of its larger counterparts. Compared to the 430i, the 420i offered significantly lower running costs but sacrificed performance. Against competitors like the Audi A5 Coupe and Mercedes-Benz C-Class Coupe, the 420i held its own in terms of driving dynamics and build quality. Fuel economy figures of around 42.8 mpg combined were competitive for its class.
Legacy
The B48 engine, used in the 420i Steptronic, has proven to be a relatively reliable powertrain. While some early examples experienced issues with oil leaks and cooling system components, these were largely addressed through software updates and revised parts. The 8-speed Steptronic transmission is also known for its durability. Today, used examples of the 420i Steptronic are readily available and represent a relatively affordable entry point into BMW ownership. The car’s combination of style, comfort, and efficiency continues to appeal to buyers seeking a premium coupe experience.
