The BMW 420i Gran Coupe (F36, facelifted in 2017) represents a compelling entry point into the 4 Series lineup, blending the practicality of a four-door coupe with BMW’s established sporting character. Produced from 2017 to 2021, this variant occupied a mid-range position, offering a balance between performance, fuel efficiency, and affordability within the broader F36 generation. The facelift brought styling updates, revised technology, and refinements to the engine range, solidifying the 420i Gran Coupe as a popular choice for buyers seeking a premium, versatile vehicle.
Technical Specifications
| Brand | BMW |
| Model | 4 Series |
| Generation | 4 Series Gran Coupe (F36, facelift 2017) |
| Type (Engine) | 420i (184 Hp) |
| Start of production | 2017 |
| End of production | 2021 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Coupe |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (urban) | 7.7-8.1 l/100 km (30.5 – 29 US mpg) |
| Fuel consumption (extra urban) | 4.7-4.9 l/100 km (50 – 48 US mpg) |
| Fuel consumption (combined) | 5.8-6.1 l/100 km (40.6 – 38.6 US mpg) |
| CO2 emissions | 134-141 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 | 8.3 kg/Hp, 121.1 Hp/tonne |
| Weight-to-torque ratio | 5.2 kg/Nm, 190.8 Nm/tonne |
| Power | 184 Hp @ 5000 rpm |
| Torque | 290 Nm @ 1350-4600 rpm (213.89 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 | 7.8 l (8.24 US qt | 6.86 UK qt) |
| Kerb Weight | 1520 kg (3351.03 lbs.) |
| Max. weight | 2080 kg (4585.62 lbs.) |
| Max load | 560 kg (1234.59 lbs.) |
| Trunk (boot) space – minimum | 480 l (16.95 cu. ft.) |
| Trunk (boot) space – maximum | 1300 l (45.91 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%) | 1400 kg (3086.47 lbs.) |
| Permitted trailer load without brakes | 695 kg (1532.21 lbs.) |
| Permitted towbar download | 75 kg (165.35 lbs.) |
| Length | 4640 mm (182.68 in.) |
| Width | 1825 mm (71.85 in.) |
| Height | 1389 mm (54.69 in.) |
| Wheelbase | 2810 mm (110.63 in.) |
| Front track | 1545 mm (60.83 in.) |
| Rear (Back) track | 1592 mm (62.68 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 | The Internal combustion engine (ICE) drives the rear wheels of the vehicle. |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 6 gears, manual transmission |
| 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 heart of the 420i Gran Coupe is BMW’s B48B20A 2.0-liter turbocharged inline-four cylinder engine. This engine is a member of BMW’s modular engine family, known for its efficiency and responsiveness. The B48 utilizes direct fuel injection, operating at a compression ratio of 11:1, and is equipped with a twin-scroll turbocharger and intercooler to minimize turbo lag and maximize power output. Peak torque of 290 Nm (213.89 lb-ft) is available from a low 1350 rpm, providing strong pulling power throughout the rev range. The engine is longitudinally mounted, driving the rear wheels. The 6-speed manual transmission was standard, offering precise shifts and a direct connection to the drivetrain.
Driving Characteristics
The 420i Gran Coupe, with its 184 hp and manual transmission, delivers a balanced driving experience. Acceleration from 0-60 mph takes approximately 7.1 seconds, making it adequately quick for everyday driving and highway merging. While not as exhilarating as the higher-powered 430i or 440i models, the 420i offers a more accessible and fuel-efficient option. The manual gearbox provides a satisfying level of driver engagement, and the rear-wheel-drive configuration contributes to a sporty feel. The gear ratios are tuned for a blend of acceleration and fuel economy, with a relatively tall sixth gear for relaxed cruising. Compared to the automatic transmission option, the manual provides more control and a more connected driving experience, though it requires more driver involvement.
Equipment & Trim Levels
The 420i Gran Coupe typically came standard with features such as automatic climate control, power-adjustable front seats, a BMW iDrive infotainment system with a 6.5-inch display screen, and a suite of safety features including ABS, stability control, and multiple airbags. Interior upholstery was typically cloth, with leatherette or full leather options available as upgrades. Common optional extras included a larger iDrive display screen, navigation system, premium sound system, sunroof, and various driver-assistance features like parking sensors and lane departure warning. Trim levels were relatively streamlined, with options primarily focused on adding individual features rather than distinct packages.
Chassis & Braking
The F36 Gran Coupe utilizes a sophisticated chassis design featuring an independent coil spring suspension at the front and an independent multi-link suspension at the rear. This setup provides a comfortable ride while maintaining good handling characteristics. The 420i Gran Coupe typically featured ventilated disc brakes on all four wheels, providing ample stopping power. The steering system is a rack-and-pinion setup with electric power assistance, offering precise and responsive steering feel. Stabilizer bars are fitted front and rear to reduce body roll during cornering.
Market Reception & Comparison
The 420i Gran Coupe was generally well-received by automotive critics as a stylish and practical entry-level option in the 4 Series range. It was praised for its fuel efficiency, comfortable ride, and engaging driving dynamics. However, some reviewers noted that the 184 hp engine could feel somewhat underpowered, particularly when fully loaded or tackling steep hills. Compared to the 430i, the 420i offered significantly lower running costs but sacrificed some performance. The 420d (diesel) variant provided similar fuel economy with more torque, but at a higher initial purchase price.
Legacy
The B48 engine in the 420i Gran Coupe has proven to be a relatively reliable powertrain, although some owners have reported issues with oil leaks and cooling system components. Regular maintenance, including oil changes and coolant flushes, is crucial for long-term reliability. On the used car market, the 420i Gran Coupe represents a good value proposition, offering a premium driving experience at a more affordable price point than its higher-powered siblings. Its blend of style, practicality, and efficiency continues to make it a popular choice for buyers seeking a versatile and well-rounded vehicle.
