The Mercedes-Benz S-Class (W223) S 450 4MATIC, produced from June 2023 through 2026, represents a significant iteration of the flagship luxury sedan. Positioned as a mid-range offering within the W223 generation, it bridges the gap between the entry-level S 350 and the higher-performance S 580 models. This variant distinguishes itself through its combination of a 3.0-liter inline-six cylinder engine with EQ Boost mild-hybrid technology, paired with a 9G-TRONIC automatic transmission and the 4MATIC all-wheel-drive system. The S 450 4MATIC aimed to deliver a refined balance of power, efficiency, and technological sophistication, appealing to buyers seeking a luxurious experience without the outright performance focus of the range-topping models.
Powertrain & Engine Architecture
At the heart of the S 450 4MATIC lies the M 256.830 engine, a 2,999 cc (183.01 cu. in.) inline-six cylinder gasoline engine. This engine utilizes direct fuel injection and is equipped with a twin-scroll turbocharger and intercooler to enhance performance and efficiency. The engine produces 381 hp (283 kW) and 500 Nm (368.78 lb-ft) of torque. A key feature of this powertrain is the integrated EQ Boost system, a 48-volt mild-hybrid system. This system incorporates a 23 hp electric motor and a 250 Nm (184.39 lb.-ft.) electric motor, positioned between the engine and the transmission. The EQ Boost system provides several benefits, including smoother start/stop operation, energy recovery during deceleration, and a limited amount of electric assistance during acceleration. The engine boasts a compression ratio of 10.5:1 and utilizes a DOHC valvetrain with four valves per cylinder.
The 9G-TRONIC automatic transmission is a nine-speed automatic gearbox designed for smooth and efficient shifting. It features a wide gear ratio spread, optimizing both acceleration and fuel economy. The transmission is electronically controlled and adapts its shift patterns based on driving conditions and driver input. The 4MATIC all-wheel-drive system provides enhanced traction and stability, particularly in adverse weather conditions. It operates with a rear-wheel bias, contributing to the vehicle’s dynamic handling characteristics.
Fuel Injection and Valvetrain Details
The M 256 engine employs a piezo direct fuel injection system, allowing for precise fuel delivery and optimized combustion. This system contributes to reduced emissions and improved fuel efficiency. The DOHC valvetrain, coupled with variable valve timing (VVT), further enhances engine performance and responsiveness across the rev range. The engine oil capacity is 8 liters (8.45 US qt | 7.04 UK qt), and the coolant capacity is 13 liters (13.74 US qt | 11.44 UK qt). The engine also incorporates a particulate filter to minimize emissions.
Driving Characteristics
The S 450 4MATIC delivers a refined and comfortable driving experience. The combination of the inline-six engine and the 9G-TRONIC transmission provides smooth and effortless acceleration. The EQ Boost system contributes to a near-instantaneous response from a standstill, enhancing the feeling of power delivery. Acceleration from 0 to 100 km/h (0-62 mph) takes approximately 5 seconds, and 0-60 mph is achieved in around 4.8 seconds. While not as overtly sporty as the S 580 with its V8 engine, the S 450 4MATIC offers ample power for confident overtaking and highway cruising. The 4MATIC all-wheel-drive system provides excellent grip and stability, inspiring confidence in various driving conditions. The air suspension system, standard on the S-Class, further contributes to ride comfort by effectively absorbing road imperfections.
The 9G-TRONIC transmission’s gear ratios are optimized for both performance and fuel efficiency. Lower gears provide strong acceleration, while higher gears allow for relaxed cruising at highway speeds. The transmission’s smooth shifting characteristics contribute to the overall refinement of the driving experience. Compared to the S 350, the S 450 offers a noticeable increase in power and responsiveness. However, it lacks the ultimate performance of the S 580.
Equipment & Trim Levels
The S 450 4MATIC comes standard with a comprehensive array of luxury features. Interior upholstery typically consists of high-quality leather, with a range of color options available. The dashboard features a large dual-screen display, incorporating the digital instrument cluster and the infotainment system. Standard features include ambient lighting, heated and ventilated front seats, a premium sound system, and a panoramic sunroof. Optional extras include rear-seat entertainment systems, massaging seats, and advanced driver-assistance features such as adaptive cruise control and lane-keeping assist. The interior trim can be customized with various wood and metal finishes.
Chassis & Braking
The S 450 4MATIC utilizes an independent multi-link suspension system at both the front and rear axles, coupled with air suspension. This combination provides a comfortable and controlled ride. The air suspension system automatically adjusts the ride height based on driving conditions and load, further enhancing comfort and stability. The braking system consists of ventilated discs at all four wheels, providing ample stopping power. Standard safety features include ABS (Anti-lock braking system) and electronic stability control. The S-Class also features 4-wheel steering (4WS, active rear steering), which enhances maneuverability at low speeds and stability at high speeds.
Market Reception & Comparison
The S 450 4MATIC was generally well-received by automotive critics. It was praised for its refined driving experience, luxurious interior, and advanced technology. Fuel economy is rated at 8-9.2 l/100 km (29.4 – 25.6 US mpg, 35.3 – 30.7 UK mpg, 12.5 – 10.9 km/l). Compared to the S 350, the S 450 offered a significant performance upgrade without the higher price tag of the S 580. In terms of reliability, the M 256 engine has proven to be generally robust, although some owners have reported minor issues with the EQ Boost system. The S 450 4MATIC represented a compelling value proposition for buyers seeking a luxurious and technologically advanced sedan.
Technical Specifications
| Body type | Sedan, 4 Doors, 5 Seats |
| Fuel economy | 8-9.2 l/100 km, 29.4 – 25.6 US mpg, 35.3 – 30.7 UK mpg, 12.5 – 10.9 km/l |
| CO2 emissions | 183-209 g/km |
| Emission standard | Euro 6e |
| Acceleration 0-100 km/h | 5 sec |
| Acceleration 0-60 mph | 4.8 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Power | 381 Hp |
| Torque | 500 Nm (368.78 lb.-ft.) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | M 256.830 |
| Engine displacement | 2999 cm3 (183.01 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 83 mm (3.27 in.) |
| Piston Stroke | 92.4 mm (3.64 in.) |
| Compression ratio | 10.5:1 |
| Fuel injection system | Direct injection |
| Engine oil capacity | 8 l (8.45 US qt | 7.04 UK qt) |
| Coolant capacity | 13 l (13.74 US qt | 11.44 UK qt) |
| Kerb Weight | 1995 kg (4398.22 lbs.) |
| Max. weight | 2795 kg (6161.92 lbs.) |
| Trunk (boot) space | 550 l (19.42 cu. ft.) |
| Fuel tank capacity | 65 l (17.17 US gal | 14.3 UK gal) |
| Gearbox | 9 gears, automatic transmission G-TRONIC |
| Front tires | 235/55 R18; 255/45 R19; 255/40 R20; 255/35 R21 |
| Rear tires | 235/55 R18; 255/45 R19; 285/40 R19; 255/40 R20; 285/35 R20; 285/30 R21 |
Legacy
The S 450 4MATIC, with its M 256 engine and EQ Boost technology, represents a transitional powertrain in Mercedes-Benz’s lineup. It showcased the brand’s commitment to both performance and efficiency, paving the way for future electrified models. On the used car market, these models are generally well-regarded, offering a compelling combination of luxury, technology, and reliability. While the EQ Boost system may require occasional attention, the M 256 engine has proven to be a durable and capable powerplant. The S 450 4MATIC continues to be a desirable option for buyers seeking a sophisticated and comfortable luxury sedan.
