The BMW 4 Series Gran Coupe (G26) 420i Steptronic, produced from 2021 to June 2024, represents a compelling entry point into the Gran Coupe lineup. Positioned as a mid-range offering, it blended the sporty aesthetics of the 4 Series with the practicality of a five-door coupe. This variant utilized a 1.6-liter turbocharged four-cylinder engine paired with an 8-speed Steptronic automatic transmission, targeting buyers seeking a balance between performance, efficiency, and comfort. It falls within the G26 generation, sharing its platform with the 3 Series sedan (G20) and other BMW models built on the modular UKL2 architecture.
Technical Specifications
| Brand | BMW |
| Model | 4 Series |
| Generation | 4 Series Gran Coupe (G26) |
| Type (Engine) | 420i (170 Hp) Steptronic |
| Start of production | 2021 |
| End of production | June, 2024 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Coupe |
| Seats | 5 |
| Doors | 5 |
| Fuel consumption (economy) – urban | 7.2-8 l/100 km (32.7 – 29.4 US mpg, 39.2 – 35.3 UK mpg, 13.9 – 12.5 km/l) |
| Fuel consumption (economy) – extra urban | 6.1-7 l/100 km (38.6 – 33.6 US mpg, 46.3 – 40.4 UK mpg, 16.4 – 14.3 km/l) |
| Fuel consumption (economy) – combined | 7.3-8.1 l/100 km (32.2 – 29 US mpg, 38.7 – 34.9 UK mpg, 13.7 – 12.3 km/l) |
| CO2 emissions | 165-183 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 8.6 sec |
| Acceleration 0 – 62 mph | 8.6 sec |
| Acceleration 0 – 60 mph | 8.2 sec |
| Maximum speed | 227 km/h (141.05 mph) |
| Weight-to-power ratio | 9.5 kg/Hp, 104.9 Hp/tonne |
| Weight-to-torque ratio | 6.5 kg/Nm, 154.3 Nm/tonne |
| Power | 170 Hp @ 5000-5500 rpm |
| Power per litre | 106.4 Hp/l |
| Torque | 250 Nm @ 2000-4400 rpm (184.39 lb.-ft. @ 2000-4400 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | B48B16A |
| Engine displacement | 1597 cm3 (97.45 cu. in.) |
| Number of cylinders | 4 |
| Engine configuration | Inline |
| Cylinder Bore | 82 mm (3.23 in.) |
| Piston Stroke | 75.6 mm (2.98 in.) |
| Compression ratio | 9:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Direct injection |
| Engine aspiration | Twin-power turbo, Intercooler |
| Valvetrain | VALVETRONIC, Double-VANOS |
| Engine oil capacity | 5.25 l (5.55 US qt | 4.62 UK qt) |
| Kerb Weight | 1620 kg (3571.49 lbs.) |
| Max. weight | 2175 kg (4795.05 lbs.) |
| Max load | 555 kg (1223.57 lbs.) |
| Trunk (boot) space – minimum | 470 l (16.6 cu. ft.) |
| Trunk (boot) space – maximum | 1290 l (45.56 cu. ft.) |
| Fuel tank capacity | 59 l (15.59 US gal | 12.98 UK gal) |
| Max. roof load | 75 kg (165.35 lbs.) |
| Permitted trailer load with brakes (8%) | 1600 kg (3527.4 lbs.) |
| Permitted trailer load with brakes (12%) | 1600 kg (3527.4 lbs.) |
| Permitted trailer load without brakes | 750 kg (1653.47 lbs.) |
| Permitted towbar download | 75 kg (165.35 lbs.) |
| Length | 4783 mm (188.31 in.) |
| Width | 1852 mm (72.91 in.) |
| Width including mirrors | 2073 mm (81.61 in.) |
| Height | 1442 mm (56.77 in.) |
| Wheelbase | 2856 mm (112.44 in.) |
| Front track | 1595 mm (62.8 in.) |
| Rear (Back) track | 1623 mm (63.9 in.) |
| Front overhang | 862 mm (33.94 in.) |
| Rear overhang | 1065 mm (41.93 in.) |
| Minimum turning circle | 12 m (39.37 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 | 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 |
| Tires size Front | 225/55 R17; 245/45 R18; 245/40 R19; 245/35 R20 |
| Tires size Rear | 225/55 R17; 245/45 R18; 255/40 R19; 255/35 R20 |
| Wheel rims size Front | 7.5J x 17; 8.5J x 18; 8.5J x 19; 8.5J x 20 |
| Wheel rims size Rear | 7.5J x 17; 8.5J x 18; 9J x 19; 9J x 20 |
Powertrain & Engine Architecture
The heart of the 420i Gran Coupe is the BMW B48B16A 1.6-liter inline-four cylinder engine. This engine is a member of BMW’s modular engine family, known for its efficient design and advanced technologies. It features direct fuel injection, a single twin-scroll turbocharger, and BMW’s VALVETRONIC variable valve timing and Double-VANOS variable camshaft timing systems. These technologies work in concert to optimize combustion, improve throttle response, and enhance fuel economy. The engine produces 170 horsepower at 5000-5500 rpm and 250 Nm (184 lb-ft) of torque between 2000-4400 rpm. The Steptronic 8-speed automatic transmission is a torque-converter type, offering smooth and quick shifts. It features adaptive shift programs that adjust to the driver’s style and road conditions.
Driving Characteristics
The 420i Steptronic delivers a comfortable and refined driving experience. While not as overtly sporty as higher-powered 4 Series variants, it provides adequate acceleration for everyday driving. The 0-60 mph sprint takes approximately 8.2 seconds, and the car has a top speed of 141 mph. The automatic transmission is well-tuned, providing seamless gear changes and contributing to a relaxed cruising experience. Compared to the manual transmission option, the Steptronic offers greater convenience, particularly in urban traffic. However, it does slightly diminish the driver’s sense of engagement. The power delivery is linear, with the turbocharger providing a noticeable boost in mid-range acceleration. The rear-wheel-drive configuration contributes to balanced handling, although it can be less forgiving in slippery conditions than all-wheel-drive alternatives.
Equipment & Trim Levels
The 420i Gran Coupe came standard with a generous array of features, including BMW’s iDrive infotainment system with a 8.8-inch touchscreen display, Apple CarPlay and Android Auto compatibility, automatic climate control, and a suite of driver-assistance systems such as lane departure warning and forward collision warning. Interior upholstery typically consisted of Sensatec leatherette, with optional upgrades to genuine leather available. Standard exterior features included LED headlights, alloy wheels, and a power tailgate. Popular optional extras included a premium sound system, a panoramic sunroof, and adaptive suspension.
Chassis & Braking
The G26 4 Series Gran Coupe utilizes a sophisticated chassis design. The front suspension features a spring strut setup with a transverse stabilizer, while the rear employs an independent multi-link spring suspension, also with a stabilizer bar. This configuration provides a good balance between ride comfort and handling precision. The braking system consists of ventilated discs on all four wheels, providing ample stopping power. Anti-lock braking system (ABS) and electronic stability control (ESC) are standard features, enhancing safety and control.
Market Reception & Comparison
The 420i Gran Coupe was generally well-received by automotive critics. It was praised for its stylish design, comfortable interior, and efficient engine. However, some reviewers noted that the 170-horsepower engine could feel underpowered for more enthusiastic drivers. Compared to the 430i and M440i variants, the 420i offered a more affordable entry point into the 4 Series range, but at the expense of outright performance. In terms of fuel economy, the 420i delivered respectable figures, averaging around 32 mpg in combined driving. Reliability reports have been generally positive, with few major issues reported.
Legacy
The BMW 420i Gran Coupe (G26) represents a well-rounded and practical offering in the premium compact coupe segment. The B48 engine has proven to be a reliable and durable unit, and the Steptronic transmission is known for its smooth operation. On the used car market, these models offer a compelling value proposition, providing a blend of luxury, performance, and efficiency at a reasonable price point. While not the most exciting variant in the 4 Series lineup, the 420i Gran Coupe remains a popular choice for buyers seeking a stylish and comfortable grand tourer.
