Technical Specifications
| Brand | BMW |
| Model | 4 Series |
| Generation | 4 Series Gran Coupe (G26 LCI, facelift 2024) |
| Type (Engine) | 420i (184 Hp) Steptronic |
| Start of production | July, 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 6e |
| 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, 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 (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.) |
| 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 | 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 | 225/55 R17 |
| Wheel rims size | 7.5J x 17 |
The BMW 4 Series Gran Coupe (G26 LCI), specifically the 420i Steptronic, represents the facelifted version of the second-generation 4 Series Gran Coupe, launched in July 2024. Positioned as the entry-level model within the Gran Coupe range, the 420i combines a 2.0-liter turbocharged four-cylinder engine with an eight-speed automatic transmission. This variant aims to provide a balance of performance, efficiency, and comfort, appealing to buyers seeking a stylish and practical grand tourer. The G26 LCI builds upon the G26 platform, which debuted in 2021, incorporating styling revisions, updated technology, and refined powertrain options.
Powertrain & Engine Architecture
The 420i Steptronic is powered by BMW’s B48B20A 2.0-liter inline-four cylinder engine. This engine employs direct fuel injection and a twin-scroll turbocharger with intercooling to achieve a balance of power and efficiency. The B48 engine family is recognized for its robust construction and advanced technologies such as VALVETRONIC (variable valve timing and lift) and Double-VANOS (variable camshaft timing). These systems optimize engine breathing for improved performance and fuel economy. The engine generates 184 horsepower at 5000-6500 rpm and 300 Nm (221 lb-ft) of torque between 1350 and 4000 rpm. The engine is mounted longitudinally, driving the rear wheels. The eight-speed Steptronic automatic transmission is a torque-converter type, offering smooth and efficient gear changes. 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 sporty as the higher-powered 4 Series models, the 184 hp engine provides sufficient performance for daily driving and highway cruising. Acceleration from 0 to 60 mph takes approximately 7.5 seconds. The Steptronic transmission contributes to smooth acceleration and minimizes gear hunting. Compared to a 420i equipped with a manual transmission, the automatic offers greater convenience, especially in city traffic. However, it may slightly reduce driver engagement. The gear ratios are optimized for a balance of acceleration and fuel efficiency, with taller gearing in higher gears for relaxed highway driving.
Equipment & Trim Levels
The 420i Steptronic typically comes standard with features such as BMW’s iDrive infotainment system with a touchscreen display, automatic climate control, power-adjustable front seats, and a suite of driver-assistance systems including lane departure warning and forward collision warning. Interior upholstery is usually a combination of synthetic leather and cloth, with optional upgrades to genuine leather available. Common optional extras include a premium sound system, a head-up display, and adaptive suspension. The LCI facelift introduced updated interior trim options and enhanced connectivity features.
Chassis & Braking
The 4 Series Gran Coupe features a sophisticated chassis design with a spring strut front suspension and an independent multi-link rear suspension. Both ends incorporate stabilizer bars to minimize body roll during cornering. The 420i is equipped with ventilated disc brakes on all four wheels, providing ample stopping power. ABS (Anti-lock Braking System) is standard. The suspension tuning prioritizes comfort, delivering a smooth ride over various road surfaces. The steering is electrically assisted, offering precise and responsive control.
Market Reception & Comparison
The 420i Steptronic was generally well-received by automotive critics as a practical and stylish entry point into the 4 Series Gran Coupe range. It was praised for its comfortable ride, refined interior, and fuel efficiency. Compared to the more powerful 430i and M440i models, the 420i offers a more affordable price point, but sacrifices some performance. Fuel economy is a strong point, with combined WLTP figures ranging from 6.6 to 7.3 l/100 km. Reliability has been generally good, with the B48 engine proving to be a durable unit.
Legacy
The B48 engine, found in the 420i Steptronic, has become a staple in BMW’s lineup and is known for its longevity and relatively low maintenance costs. The G26 generation 4 Series Gran Coupe, including the 420i variant, has established itself as a popular choice in the premium compact executive car segment. In the used car market, well-maintained 420i models are sought after for their blend of style, practicality, and affordability. The Steptronic transmission, while not as engaging as a manual, is generally reliable and contributes to the car’s overall ease of use.
