The Mercedes-Benz S 450, produced between 2009 and 2010, was a variant of the W221 S-Class facelift, representing a mid-range offering within the extensive S-Class lineup. Positioned above the S 350 and below the more powerful S 550 and S 63 AMG models, the S 450 aimed to provide a balance of performance, luxury, and efficiency for discerning buyers. It featured a naturally aspirated 4.7-liter V8 engine paired with the 7G-TRONIC automatic transmission, offering a refined driving experience characteristic of the S-Class. The W221 generation, launched in 2005, was a significant step forward for Mercedes-Benz, incorporating advanced technology and a focus on passenger comfort.
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 produced 340 horsepower (Hp) at 6000 rpm and 460 Newton-meters (339.28 lb-ft) of torque between 2700 and 5000 rpm. The engine utilizes a three-valve per cylinder design (two intake, one exhaust) and multi-port fuel injection. The M273 engine family was known for its smooth operation and relatively high power output for its displacement. It featured a silencer rail within the intake manifold to reduce intake noise, contributing to the S-Class’s quiet cabin.
The 7G-TRONIC automatic transmission, a seven-speed unit, was a key component of the S 450’s drivetrain. This transmission offered smooth and responsive shifts, contributing to both performance and fuel efficiency. It featured a torque converter lock-up clutch that engaged in multiple gears, reducing slippage and improving fuel economy. The transmission also included a manual shift mode, allowing drivers to select gears for more control, although the emphasis remained on providing a seamless automatic experience. The transmission was longitudinally mounted, driving the rear wheels.
Engine Code Specifics
The M273.922 engine code designates this specific variant of the 4.7L V8. Early versions of the M273 engine were known to experience issues with balance shaft sprocket wear, potentially leading to engine noise. Mercedes-Benz addressed this issue with revised components in later production years, including those used in the 2009-2010 S 450. Regular oil changes with the correct specification oil were crucial for maintaining the longevity of this engine.
Driving Characteristics
The S 450 offered a comfortable and refined driving experience. While not as overtly sporty as the higher-powered S 550 or AMG models, the 340 hp V8 provided ample power for effortless cruising and confident acceleration. The 0-60 mph acceleration time was approximately 5.6 seconds, and the car had an electronically limited top speed of 155 mph (250 km/h). The 7G-TRONIC transmission contributed to smooth gear changes, minimizing disruptions to the driving experience. The gear ratios were tuned for a balance of acceleration and fuel efficiency, with a relatively tall final drive ratio prioritizing highway comfort. Compared to the S 350, the S 450 offered noticeably more power and a more relaxed feel, particularly when overtaking or merging onto highways. The S 550, with its larger displacement V8, provided even greater performance but at the expense of fuel economy.
Equipment & Trim Levels
The S 450 came standard with a comprehensive array of luxury features, befitting its position in the S-Class range. Standard equipment typically included leather upholstery, wood trim, a premium sound system, dual-zone automatic climate control, power-adjustable front seats with memory function, and a sunroof. The S-Class was also equipped with a host of safety features, including ABS, traction control, stability control, and multiple airbags. Optional extras included features such as a rear seat entertainment system, massaging seats, a panoramic sunroof, and advanced driver-assistance systems like Distronic Plus (adaptive cruise control) and Pre-Safe brake assist. Interior color options were extensive, allowing buyers to personalize their vehicle. The dashboard layout was characterized by a blend of traditional Mercedes-Benz elegance and modern technology.
Chassis & Braking
The S 450 utilized a fully independent suspension system, featuring multi-link front and rear suspension. This suspension design provided a comfortable ride while maintaining good handling characteristics. Air suspension was standard, allowing the ride height to be adjusted for improved comfort or ground clearance. The S 450 was equipped with disc brakes on all four wheels, providing ample stopping power. ABS (Anti-lock Braking System) was standard, along with electronic brake-force distribution and brake assist. The car’s weight distribution was carefully balanced to enhance handling stability. Stabilizer bars were fitted to both the front and rear axles to reduce body roll during cornering.
Market Reception & Comparison
The S 450 was generally well-received by automotive critics, who praised its smooth engine, comfortable ride, and luxurious interior. It was seen as a strong contender in the luxury sedan segment, offering a compelling alternative to rivals from BMW and Audi. Fuel economy was considered reasonable for a vehicle of its size and performance, with combined fuel consumption figures ranging from 22.2 to 22 US mpg. However, some critics noted that the S 450 lacked the outright performance of the S 550 and AMG models. In terms of reliability, the M273 engine was generally considered to be robust, but as mentioned earlier, early versions were susceptible to balance shaft sprocket wear. The 7G-TRONIC transmission was also generally reliable, but required regular maintenance to ensure smooth operation.
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 |
| Engine Configuration | V-engine |
| Compression Ratio | 10.5:1 |
| Fuel Injection System | Multi-port manifold injection |
| Power | 340 Hp @ 6000 rpm |
| Torque | 460 Nm @ 2700-5000 rpm / 339.28 lb.-ft. @ 2700-5000 rpm |
| Acceleration 0-100 km/h | 5.9 sec |
| Acceleration 0-60 mph | 5.6 sec |
| Maximum Speed | 250 km/h / 155.34 mph |
| Fuel Consumption (Urban) | 15.9-16 l/100 km / 14.8 – 14.7 US mpg / 17.8 – 17.7 UK mpg |
| Fuel Consumption (Extra Urban) | 7.7-7.8 l/100 km / 30.5 – 30.2 US mpg / 36.7 – 36.2 UK mpg |
| Fuel Consumption (Combined) | 10.6-10.7 l/100 km / 22.2 – 22 US mpg / 26.6 – 26.4 UK mpg |
| CO2 Emissions | 249-251 g/km |
| Kerb Weight | 1880 kg / 4144.69 lbs. |
| Fuel Tank Capacity | 90 l / 23.78 US gal / 19.8 UK gal |
| Transmission | 7 gears, automatic transmission G-TRONIC |
| Drive Type | Rear wheel drive |
Legacy
The S 450, while a relatively short-lived variant, remains a desirable used car option for those seeking a luxurious and comfortable S-Class experience. The M273 engine, when properly maintained, has proven to be a durable and reliable powerplant. However, potential buyers should be aware of the potential for balance shaft sprocket wear and ensure that the vehicle has been regularly serviced. The 7G-TRONIC transmission is also relatively reliable, but requires fluid changes according to the manufacturer’s recommendations. Today, the S 450 represents a good value proposition in the used luxury car market, offering a blend of performance, comfort, and features at a more affordable price point than newer S-Class models.
