The Mercedes-Benz S 450, produced from 2017 to 2020 as part of the W222 facelift generation of the S-Class, represented a significant step in luxury and technology. This variant occupied a mid-range position within the S-Class lineup, slotting between the entry-level S 350d (in markets where offered) and the higher-performance S 560 models. The S 450 distinguished itself through the integration of EQ Boost, a 48-volt mild hybrid system, enhancing both fuel efficiency and driving dynamics. It was designed to appeal to buyers seeking a refined and technologically advanced luxury sedan without the outright performance focus of the AMG variants or the top-tier V12 models.
Powertrain & Engine Architecture
The heart of the S 450 is the M 256 3.0-liter inline-six cylinder engine, internally designated as M 256.930. This engine is a marvel of modern engineering, featuring direct injection, a twin-scroll turbocharger with intercooling, and a sophisticated four-valve-per-cylinder DOHC valvetrain. It produces 367 horsepower at 5500-6100 rpm and 500 Nm (368.78 lb-ft) of torque between 1600-4000 rpm, resulting in a power-to-liter ratio of 122.4 hp/l. The engine’s design prioritizes smoothness and refinement, characteristics highly valued in the S-Class.
Crucially, the S 450 incorporates Mercedes-Benz’s EQ Boost system. This mild hybrid system utilizes a 48-volt electrical architecture and integrates a 22 hp electric motor between the engine and the 9G-TRONIC nine-speed automatic transmission. The electric motor provides supplemental power during acceleration, allowing for quicker response and improved fuel economy. It also enables features like ‘glide sailing’ where the engine shuts off during coasting, further enhancing efficiency. The system’s 0.9 kWh lithium-ion battery is relatively small, emphasizing assistance rather than full electric driving capability.
G-TRONIC Transmission
The 9G-TRONIC automatic transmission is a key component of the S 450’s powertrain. This nine-speed automatic is known for its smooth and efficient operation. The wide range of gears allows for optimized engine speed across a variety of driving conditions, contributing to both performance and fuel economy. The transmission is electronically controlled and features adaptive shift programs that learn the driver’s style. It is designed to provide seamless gear changes and a refined driving experience, perfectly complementing the S-Class’s luxury character.
Driving Characteristics
The S 450 delivers a driving experience focused on comfort and effortless power. The EQ Boost system provides a noticeable surge of torque during acceleration, making the car feel responsive despite its substantial weight. The 0-60 mph acceleration time is approximately 4.8 seconds, and 0-100 km/h takes 5.1 seconds, placing it firmly in the performance luxury category. However, the S 450 isn’t about aggressive driving; it’s about providing a serene and composed experience. The engine is remarkably quiet and refined, and the transmission shifts smoothly and predictably.
Compared to the S 560 with its larger V8 engine, the S 450 offers slightly less outright acceleration. However, the EQ Boost system helps to mitigate this difference, providing a similar level of responsiveness in everyday driving situations. The S 450 also feels more balanced than the heavier V8 models, contributing to a more agile feel in corners. Compared to diesel variants (like the S 350d), the S 450 offers a smoother and more refined power delivery, albeit with potentially higher fuel consumption depending on driving style.
Equipment & Trim Levels
The S 450 came standard with a comprehensive array of luxury features. Interior appointments typically included high-quality leather upholstery, wood trim, and brushed aluminum accents. Standard equipment included Mercedes-Benz’s COMAND infotainment system with a large central display screen, a premium sound system, and a suite of driver-assistance technologies such as adaptive cruise control, lane-keeping assist, and automatic emergency braking.
Optional extras were plentiful, allowing buyers to personalize their S 450 to their exact preferences. These included features like massaging seats, a rear-seat entertainment system, a panoramic sunroof, and upgraded leather options. The S 450 could also be equipped with Mercedes-Benz’s AIRMATIC suspension, which provided an exceptionally smooth and comfortable ride. Trim levels were generally differentiated by the availability of these optional packages and cosmetic enhancements.
Chassis & Braking
The S 450 utilizes a sophisticated chassis design focused on ride comfort and handling balance. It features an independent multi-link suspension at both the front and rear, providing excellent wheel control and a smooth ride over uneven surfaces. The suspension is tuned to prioritize comfort, but it also offers a reasonable level of handling precision.
Braking duties are handled by ventilated discs at all four corners. The braking system is equipped with ABS (Anti-lock Braking System) and electronic brake-force distribution, ensuring safe and controlled stopping performance. The S 450’s steering is electrically assisted, providing precise and responsive steering feel. The car’s weight of 1920 kg (4232.88 lbs) necessitates a robust braking system to provide adequate stopping power.
Market Reception & Comparison
The S 450 was generally well-received by automotive critics. It was praised for its refined engine, smooth transmission, luxurious interior, and advanced technology. The EQ Boost system was seen as a positive addition, enhancing both fuel efficiency and driving dynamics. However, some critics noted that the S 450 lacked the outright performance of the S 560 models.
In terms of fuel economy, the S 450 offered a combined fuel consumption of 6.6-6.6 l/100 km (35.6 – 35.6 US mpg, 42.8 – 42.8 UK mpg, 15.2 – 15.2 km/l). This was generally better than the S 560, but slightly worse than the diesel-powered S 350d. Reliability reports suggest that the M 256 engine has proven to be relatively reliable, although the complex EQ Boost system could potentially require more maintenance over the long term.
Technical Specifications
| Body type | Sedan, 4 Doors, 4-5 Seats |
| Fuel economy (combined) | 6.6-6.6 l/100 km (35.6 – 35.6 US mpg, 42.8 – 42.8 UK mpg, 15.2 – 15.2 km/l) |
| CO2 emissions | 150-157 g/km |
| Maximum speed | 250 km/h (155.34 mph) |
| Acceleration 0-100 km/h | 5.1 sec |
| Acceleration 0-60 mph | 4.8 sec |
| Engine Type | Petrol (Gasoline) |
| Engine Displacement | 2999 cm3 (183.01 cu. in.) |
| Number of Cylinders | 6 (Inline) |
| Power | 367 Hp @ 5500-6100 rpm |
| Torque | 500 Nm @ 1600-4000 rpm (368.78 lb.-ft. @ 1600-4000 rpm) |
| Engine Model/Code | M 256.930 |
| Transmission | 9-speed automatic (G-TRONIC) |
| Kerb Weight | 1920 kg (4232.88 lbs.) |
| Fuel Tank Capacity | 70 l (18.49 US gal, 15.4 UK gal) |
| Trunk (boot) space | 510 l (18.01 cu. ft.) |
| Electric Motor Power | 22 Hp |
| Electric Motor Torque | 250 Nm (184.39 lb.-ft.) |
Legacy
The Mercedes-Benz S 450, with its M 256 engine and EQ Boost technology, represents a transitional point in the S-Class lineage. It showcased Mercedes-Benz’s commitment to both luxury and efficiency, paving the way for further electrification in subsequent models. On the used car market, the S 450 offers a compelling value proposition, providing a high level of luxury and technology at a more accessible price point than the higher-end S-Class variants. The M 256 engine has proven to be relatively durable, making the S 450 a potentially reliable choice for buyers seeking a sophisticated and comfortable luxury sedan. However, prospective buyers should be mindful of the potential maintenance costs associated with the EQ Boost system and ensure that the vehicle has been properly maintained.
