The Mercedes-Benz CLS 550 V8 (C218 facelift) represents the pinnacle of performance within the second-generation CLS lineup, produced from 2014 to 2017. Positioned as the range-topping engine option, it combined a potent twin-turbocharged V8 engine with Mercedes-Benz’s advanced 9G-TRONIC nine-speed automatic transmission. This variant aimed to deliver a luxurious grand touring experience with substantial power and refined handling, appealing to buyers seeking both prestige and performance in a four-door coupe body style. The C218 facelift brought styling updates and technological enhancements to the CLS, solidifying its position as a desirable alternative to traditional sedans.
Technical Specifications
| Brand | Mercedes-Benz |
| Model | CLS |
| Generation | CLS coupe (C218 facelift, 2014) |
| Type (Engine) | CLS 550 V8 (402 Hp) 9G-TRONIC |
| Start of production | 2014 |
| End of production | 2017 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Coupe |
| Seats | 4 |
| Doors | 4 |
| Fuel consumption (economy) – urban (EPA) | 13.1-13.8 l/100 km (18 – 17 US mpg, 21.6 – 20.5 UK mpg, 7.6 – 7.2 km/l) |
| Fuel consumption (economy) – extra urban (EPA) | 9 l/100 km (26.1 US mpg, 31.4 UK mpg, 11.1 km/l) |
| Fuel consumption (economy) – combined (EPA) | 11.2 l/100 km (21 US mpg, 25.2 UK mpg, 8.9 km/l) |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 60 mph | 4.9 sec |
| Maximum speed | 250 km/h (155.34 mph), Electronically limited |
| Weight-to-power ratio | 4.7 kg/Hp, 213.1 Hp/tonne |
| Weight-to-torque ratio | 3.1 kg/Nm, 318.1 Nm/tonne |
| Power | 402 Hp @ 5000-5750 rpm |
| Power per litre | 86.2 Hp/l |
| Torque | 600 Nm @ 1600-4750 rpm (442.54 lb.-ft. @ 1600-4750 rpm) |
| Maximum engine speed | 6300 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | M 278.922 |
| Engine displacement | 4663 cm3 (284.55 cu. in.) |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 92.9 mm (3.66 in.) |
| Piston Stroke | 86 mm (3.39 in.) |
| Compression ratio | 10.5:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Direct injection |
| Engine aspiration | BiTurbo, Intercooler |
| Valvetrain | DOHC |
| Engine oil capacity | 8 l (8.45 US qt | 7.04 UK qt) |
| Coolant | 12.3 l (13 US qt | 10.82 UK qt) |
| Kerb Weight | 1886-1920 kg (4157.92 – 4232.88 lbs.) |
| Trunk (boot) space – minimum | 520 l (18.36 cu. ft.) |
| Fuel tank capacity | 80 l (21.13 US gal | 17.6 UK gal) |
| Length | 4940 mm (194.49 in.) |
| Width | 1881 mm (74.06 in.) |
| Width including mirrors | 2075 mm (81.69 in.) |
| Height | 1418 mm (55.83 in.) |
| Wheelbase | 2874 mm (113.15 in.) |
| Front track | 1596 mm (62.83 in.) |
| Rear (Back) track | 1626 mm (64.02 in.) |
| Front overhang | 902 mm (35.51 in.) |
| Rear overhang | 1165 mm (45.87 in.) |
| Minimum turning circle (turning diameter) | 11.2 m (36.75 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 | 9 gears, automatic transmission G-TRONIC |
| Front suspension | Independent multi-link suspension, Transverse stabilizer, Air suspension |
| Rear suspension | Independent multi-link suspension, Air suspension, Transverse stabilizer |
| Front brakes | Ventilated discs, 360 mm |
| Rear brakes | Ventilated discs, 320 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Electric Steering |
| Tires size | Front wheel tires: 255/40 R18Rear wheel tires: 285/35 R18 |
| Wheel rims size | Front wheel rims: 8.5J x 18Rear wheel rims: 9.5J x 18 |
Powertrain & Engine Architecture
The heart of the CLS 550 V8 is the M278.922 4.7-liter V8 engine. This engine utilizes direct fuel injection and twin turbochargers to deliver a substantial 402 horsepower and 442 lb-ft of torque. The twin-turbo setup employs one turbocharger per cylinder bank, minimizing turbo lag and providing a broad, flat torque curve. The engine features a DOHC (Dual Overhead Camshaft) valvetrain with four valves per cylinder, optimizing airflow for increased power output. The 9G-TRONIC nine-speed automatic transmission is a key component, offering a wide range of gear ratios to improve both fuel efficiency and acceleration. This transmission allows the engine to operate within its optimal power band more frequently, contributing to a responsive driving experience. The transmission features paddle shifters for manual control, although the automatic mode is generally well-tuned for most driving situations.
Driving Characteristics
The CLS 550 V8 delivers a refined yet potent driving experience. The 4.9-second 0-60 mph acceleration time is indicative of its performance capabilities. The 9G-TRONIC transmission provides smooth and quick shifts, and the wide gear ratio spread allows for relaxed cruising at highway speeds while still providing ample power for overtaking. Compared to the CLS 400 (with its smaller V6 engine) or the diesel-powered CLS 350 CDI, the 550 offers significantly more power and a more engaging driving experience. While not as overtly sporty as some dedicated performance coupes, the CLS 550 strikes a good balance between comfort and performance. The air suspension, standard on this model, contributes to a smooth ride quality, absorbing bumps and imperfections in the road effectively.
Equipment & Trim Levels
The CLS 550 V8 typically came well-equipped as standard. Features included leather upholstery, heated and ventilated front seats, a premium sound system, a navigation system, and a panoramic sunroof. Optional extras included advanced driver-assistance systems such as adaptive cruise control, lane-keeping assist, and a head-up display. Interior trim options included various wood veneers and metallic accents, allowing buyers to personalize the cabin to their preferences. The standard dashboard configuration featured a large central display screen controlled by a rotary dial and touchpad, providing access to various vehicle functions and infotainment options.
Chassis & Braking
The CLS 550 V8 utilized an independent multi-link suspension system at both the front and rear, providing a comfortable and controlled ride. Air suspension was standard, allowing for adjustable ride height and damping settings. Braking duties were handled by ventilated discs at all four corners, providing ample stopping power. The front brakes measured 360mm in diameter, while the rear brakes were 320mm. ABS (Anti-lock Braking System) was standard, enhancing safety and stability during hard braking maneuvers. The steering system employed an electric power steering rack and pinion, offering precise and responsive steering feel.
Market Reception & Comparison
The CLS 550 V8 was generally well-received by automotive critics, who praised its powerful engine, luxurious interior, and refined driving experience. However, some critics noted that the fuel economy was relatively low, especially considering the size of the engine. Compared to the CLS 400, the 550 offered a significant performance upgrade but came at a higher price point. The diesel-powered CLS 350 CDI offered better fuel economy but lacked the V8’s outright power and refinement. The CLS 550 competed with other luxury four-door coupes such as the BMW 6 Series Gran Coupe and the Audi A7.
Legacy
The M278 engine, while complex, has proven to be relatively reliable when properly maintained. Common issues include occasional turbocharger failures and oil leaks, but these are not widespread. The 9G-TRONIC transmission has also demonstrated good durability. In the used car market, the CLS 550 V8 remains a desirable option for buyers seeking a luxurious and powerful grand tourer. However, potential buyers should be aware of the higher maintenance costs associated with a high-performance V8 engine and the complexity of the vehicle’s advanced technology. The CLS 550 V8 represents a compelling blend of performance, luxury, and style, solidifying its place as a significant model within the Mercedes-Benz lineup.
