Technical Specifications
| Brand | BMW |
| Model | 4 Series |
| Generation | 4 Series Gran Coupe (G26) |
| Type (Engine) | 420i (184 Hp) Steptronic |
| Start of production | June, 2021 |
| End of production | June, 2024 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Coupe |
| Seats | 5 |
| Doors | 5 |
| Combined fuel consumption (WLTP) | 6.6-7.3 l/100 km (35.6 – 32.2 US mpg, 42.8 – 38.7 UK mpg, 15.2 – 13.7 km/l) |
| CO2 emissions (WLTP) | 150-166 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 7.9 sec |
| Acceleration 0 – 62 mph | 7.9 sec |
| Acceleration 0 – 60 mph | 7.5 sec |
| Maximum speed | 235 km/h (146.02 mph) |
| Emission standard | Euro 6d |
| Weight-to-power ratio | 8.8 kg/Hp, 113.6 Hp/tonne |
| Weight-to-torque ratio | 5.4 kg/Nm, 185.2 Nm/tonne |
| Power | 184 Hp @ 5000-6500 rpm |
| Power per litre | 92.1 Hp/l |
| Torque | 300 Nm @ 1350-4000 rpm (221.27 lb.-ft. @ 1350-4000 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 |
| Valvetrain | VALVETRONIC |
| Engine oil capacity | 5.25 l (5.55 US qt | 4.62 UK qt) |
| Coolant | 10 l (10.57 US qt | 8.8 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 (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.) |
| 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.) |
| Ride height (ground clearance) | 140 mm (5.51 in.) |
| Drag coefficient (Cd) | 0.26 |
| Minimum turning circle (turning diameter) | 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 | Double wishbone |
| 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 | 225/55 R17 101Y XL |
| Wheel rims size | 7.5J x 17 |
The BMW 4 Series Gran Coupe (G26) 420i Steptronic, produced from June 2021 to June 2024, serves as an accessible entry point into the Gran Coupe range. Positioned as a mid-range offering, it strikes a balance between performance, efficiency, and practicality within the broader 4 Series family. This variant was designed to attract buyers who desired a stylish, comfortable, and technologically advanced vehicle without incurring the higher costs associated with the more powerful models like the M440i. It is part of the G26 generation, sharing its underlying platform and many features with the 3 Series sedan and other 4 Series body styles.
Powertrain & Engine Architecture
The 420i Gran Coupe is powered by BMW’s B48B20A 2.0-liter inline-four cylinder engine. This engine is part of BMW’s modular engine family, renowned for its efficiency and refinement. It incorporates direct fuel injection, a single twin-scroll turbocharger, and BMW’s VALVETRONIC variable valve timing and lift system. VALVETRONIC provides precise control over valve timing and lift, optimizing engine performance and fuel economy across a diverse range of driving conditions. The engine generates 184 horsepower between 5000 and 6500 rpm, and 300 Nm (221 lb-ft) of torque from 1350 to 4000 rpm. This torque curve delivers responsive performance from low engine speeds, making it well-suited for everyday driving. The engine is coupled with BMW’s 8-speed Steptronic automatic transmission, known for its smooth and rapid gear changes, enhancing both performance and comfort. The transmission programming prioritizes efficiency, but also includes manual shift modes for a more engaging driving experience.
Driving Characteristics
The 420i Steptronic provides a comfortable and refined driving experience. While not as aggressively sporty as the higher-powered 4 Series models, it offers sufficient performance for most driving scenarios. Acceleration from 0-60 mph is achieved in approximately 7.5 seconds. The automatic transmission is well-calibrated, providing seamless gear changes and maintaining the engine within its optimal power band. Compared to a 420i equipped with a manual transmission, the Steptronic version emphasizes ease of use and comfort over direct driver involvement. The gear ratios are optimized for fuel efficiency, which is particularly noticeable during highway driving. However, the transmission responds quickly when downshifting for overtaking. The rear-wheel-drive configuration contributes to balanced handling, although it doesn’t provide the same level of grip as the xDrive all-wheel-drive system available on other 4 Series models.
Equipment & Trim Levels
The 420i Gran Coupe typically came standard with a comprehensive set of features. These included BMW’s iDrive infotainment system with a central touchscreen display, navigation, Apple CarPlay and Android Auto compatibility, and a premium sound system. Standard interior appointments included leatherette upholstery, power-adjustable front seats, and dual-zone automatic climate control. Optional extras included genuine leather upholstery, a panoramic sunroof, a head-up display, and advanced driver-assistance systems such as adaptive cruise control and lane-keeping assist. Trim levels varied depending on the market, but generally offered packages that combined popular options.
Chassis & Braking
The G26 4 Series Gran Coupe features a sophisticated chassis engineered to balance ride comfort and handling. The front suspension utilizes a double wishbone design, while the rear suspension employs an independent multi-link setup. This configuration delivers a good balance of ride quality and precise handling characteristics. The 420i typically came equipped with ventilated disc brakes on all four wheels, providing ample stopping power. ABS (Anti-lock Braking System) and electronic stability control are standard safety features. The steering is electrically assisted, offering a precise and responsive feel.
Market Reception & Comparison
The 420i Gran Coupe received generally positive reviews from automotive critics. It was praised for its stylish design, comfortable interior, and refined driving experience. However, some critics noted that the 184-horsepower engine could feel somewhat underpowered for more enthusiastic drivers, particularly when compared to the more potent 430i and M440i models. In terms of fuel economy, the 420i offered competitive figures for its class, achieving around 35.6-32.2 US mpg combined. Reliability reports have been generally favorable, with the B48 engine proving to be a robust and dependable unit.
Legacy
The BMW 4 Series Gran Coupe (G26) 420i Steptronic represents a well-rounded and practical luxury vehicle. The B48 engine and 8-speed Steptronic transmission have demonstrated reliability and efficiency. In the used car market, these models offer good value, providing a blend of style, comfort, and technology at a more accessible price point than the higher-performance variants. While not the most exhilarating 4 Series to drive, the 420i remains a compelling choice for buyers seeking a refined and practical grand tourer.
