The Mercedes-Benz S 450, produced between 2006 and 2009, was a key variant within the W221 generation of the S-Class. Positioned as a mid-range offering in the lineup, it bridged the gap between the entry-level S 350 and the more powerful S 550 and S 600 models. The S 450 combined a naturally aspirated 4.7-liter V8 engine with the 7G-TRONIC seven-speed automatic transmission, offering a balance of performance, luxury, and relative fuel efficiency for the time. It represented a significant evolution of the S-Class, building upon the technological advancements introduced in the preceding W220 generation and setting the stage for future innovations in the flagship sedan.
Powertrain & Engine Architecture
The heart of the S 450 is the M273.922 engine, a 4.7-liter (4663 cc) naturally aspirated V8. This engine is characterized by its smooth operation and robust construction. It features a three-valve per cylinder design (two intake, one exhaust) and utilizes multi-port fuel injection. The engine produces 340 horsepower at 6000 rpm and 460 Nm (339.28 lb-ft) of torque between 2700 and 5000 rpm. The cylinder bore measures 92.9 mm (3.66 in) and the piston stroke is 86 mm (3.39 in), resulting in a compression ratio of 10.5:1. The engine is longitudinally mounted at the front of the vehicle.
The 7G-TRONIC automatic transmission, designated as 722.906, is a seven-speed unit that was a significant advancement over previous Mercedes-Benz automatic transmissions. It offered smoother shifts, improved fuel economy, and a wider gear ratio spread. The transmission features a torque converter lock-up clutch that engages in multiple gears to reduce slippage and improve efficiency. It also incorporates a manual shift mode, allowing the driver to select gears for more control. The transmission was known for its reliability and refinement, contributing significantly to the overall driving experience of the S 450.
Engine Management and Fuel System
The M273 engine utilizes a sophisticated engine management system to control fuel injection, ignition timing, and other parameters. The multi-port fuel injection system delivers fuel directly to the intake ports, ensuring efficient combustion. The engine also features a variable intake manifold that optimizes airflow at different engine speeds. The fuel system is designed to operate on premium unleaded gasoline. Engine oil capacity is 8.5 liters (8.98 US qt / 7.48 UK qt) and coolant capacity is also 8.5 liters.
Driving Characteristics
The S 450 offered a refined and comfortable driving experience. The 4.7-liter V8 provided ample power for both city and highway driving, with a 0-60 mph acceleration time of approximately 5.6 seconds and a 0-100 km/h time of 5.9 seconds. While not as overtly sporty as the higher-powered S 550, the S 450 delivered a smooth and effortless surge of power. The 7G-TRONIC transmission contributed to this smoothness, providing seamless gear changes. The gear ratios were optimized for both acceleration and fuel economy. Compared to the S 350, the S 450 offered noticeably more power and a more responsive feel. However, it lacked the outright performance of the S 550 and S 600 models.
The rear-wheel drive configuration provided a balanced handling characteristic, although it wasn’t particularly engaging for enthusiastic drivers. The focus was firmly on comfort and stability. The air suspension system, standard on the S 450, further enhanced ride quality, absorbing bumps and imperfections in the road with ease.
Equipment & Trim Levels
The S 450 came standard with a comprehensive array of luxury features. Interior upholstery typically consisted of leather, with a choice of colors and trim options. Standard features included power-adjustable front seats with memory function, dual-zone automatic climate control, a premium audio system, and a multi-function steering wheel. The dashboard featured wood trim and a high-resolution display screen for the infotainment system. Optional extras included a rear seat entertainment system, a panoramic sunroof, massaging seats, and advanced driver-assistance systems such as Distronic adaptive cruise control and Parktronic parking assist.
Trim levels were relatively limited, with most customization options available through individual selections rather than distinct packages. Buyers could choose from a range of exterior colors and interior trim combinations to personalize their S 450.
Chassis & Braking
The W221 S-Class, including the S 450, featured a robust chassis designed for both comfort and safety. The front suspension utilized an air suspension system, providing a smooth and controlled ride. The rear suspension also employed an air suspension system, further enhancing ride quality. The braking system consisted of ventilated discs on all four wheels, providing ample stopping power. Anti-lock braking system (ABS) was standard, along with electronic brake-force distribution. The steering system was a rack and pinion type, offering precise and responsive steering feel. Standard tire size was 235/55 R17, mounted on 17-inch alloy wheels.
Market Reception & Comparison
The S 450 was generally well-received by automotive critics. It was praised for its comfortable ride, refined interior, and smooth powertrain. However, some critics noted that it lacked the outright performance of the higher-powered S-Class models. Fuel economy was considered reasonable for a large luxury sedan, with combined fuel consumption ranging from 11.2 to 11.4 l/100 km (21-20.6 US mpg). Compared to the S 350, the S 450 offered a noticeable improvement in performance, while remaining more affordable than the S 550. Reliability was generally good, although some owners reported issues with the air suspension system and electronic components. CO2 emissions ranged from 267-272 g/km.
Technical Specifications
| Body Type | Sedan, 4 Doors, 5 Seats |
| Engine Type | Petrol (Gasoline) |
| Engine Displacement | 4663 cm3 (284.55 cu. in.) |
| Number of Cylinders | 8 (V-engine) |
| Power | 340 Hp @ 6000 rpm |
| Torque | 460 Nm @ 2700-5000 rpm (339.28 lb.-ft.) |
| Fuel Consumption (Urban) | 16.5-16.7 l/100 km (14.3 – 14.1 US mpg) |
| Fuel Consumption (Extra Urban) | 8.1-8.3 l/100 km (29 – 28.3 US mpg) |
| Fuel Consumption (Combined) | 11.2-11.4 l/100 km (21 – 20.6 US mpg) |
| Acceleration 0-100 km/h | 5.9 sec |
| Acceleration 0-60 mph | 5.6 sec |
| Maximum Speed | 250 km/h (155.34 mph) |
| Kerb Weight | 1865 kg (4111.62 lbs.) |
| Max. Weight | 2545 kg (5610.76 lbs.) |
| Trunk (Boot) Space | 560 l (19.78 cu. ft.) |
| Fuel Tank Capacity | 90 l (23.78 US gal) |
| Transmission | 7-speed automatic (7G-TRONIC) |
| Drive Type | Rear Wheel Drive |
| Length | 5079 mm (199.96 in.) |
| Width | 1872 mm (73.7 in.) |
| Height | 1473 mm (57.99 in.) |
Legacy
The S 450, while not the most sought-after variant of the W221 S-Class, remains a desirable used car option. The M273 engine is known for its durability, although regular maintenance is essential. The 7G-TRONIC transmission is also generally reliable. Common issues include air suspension failures and problems with electronic components, which can be costly to repair. Today, the S 450 represents a relatively affordable entry point into the world of Mercedes-Benz luxury, offering a comfortable and refined driving experience at a reasonable price. Its blend of performance, luxury, and technology continues to appeal to buyers seeking a sophisticated and well-equipped sedan.
