Mercedes-AMG has long been synonymous with high-performance vehicles, and at the heart of this legacy lies the formidable V8 engine. The Mercedes-AMG 4.0-liter V8 biturbo engine represents the latest chapter in this powerful lineage, a technological marvel engineered to deliver exhilarating performance while embracing efficiency and innovation. This engine, internally designated as M178, is not merely an evolution; it’s a revolution, setting new benchmarks in sports car engine design and solidifying AMG’s commitment to “Driving Performance.”
Developed entirely in-house by Mercedes-AMG GmbH in Affalterbach, Germany, the 4.0-liter V8 biturbo is a testament to the brand’s engineering prowess. This engine is designed to power some of the most dynamic vehicles in the Mercedes-AMG range, starting with the iconic AMG GT. From its inception, the goal was clear: to create a V8 engine that not only delivers raw power but also embodies intelligent design for optimized responsiveness, reduced emissions, and a thrilling driving experience.
Tobias Moers, former Chairman of the Board of Management of Mercedes-AMG GmbH, emphasized the engine’s significance: “V8 engines are an integral part of the AMG philosophy and the brand’s commitment to ‘Driving Performance’. The V8 biturbo engine for our new GT is going to delight our customers!”
Christian Enderle, Head of Engine and Powertrain Development at Mercedes-AMG, further highlighted the engine’s advancements: “The new AMG 4.0-liter V8 biturbo sees us presenting an exciting and powerful sports car engine which, thanks to a number of measures, also represents the next step in efficiency.”
Key Innovations: ‘Hot Inside V’ and Dry Sump Lubrication
The Mercedes-AMG 4.0-liter V8 biturbo engine distinguishes itself through several groundbreaking features, most notably its “hot inside V” configuration and dry sump lubrication system. These innovations are not just about technical novelty; they are crucial in enhancing the engine’s performance and dynamics in real-world driving scenarios.
‘Hot Inside V’ Turbocharging
Traditional V8 engine designs typically place turbochargers on the exterior of the cylinder banks. However, the AMG 4.0-liter V8 biturbo adopts a revolutionary approach by positioning the two turbochargers within the V-angle of the cylinder banks. This “hot inside V” layout offers significant advantages:
- Compact Engine Design: By nesting the turbos within the V, the engine’s overall dimensions are considerably reduced. This compactness allows for more flexible engine bay packaging and contributes to better weight distribution within the vehicle.
- Optimized Response: The close proximity of the turbochargers to the exhaust manifolds minimizes the exhaust gas flow path to the turbine wheels. This reduction in distance results in quicker turbo spooling and virtually eliminates turbo lag, providing instantaneous throttle response that’s crucial for sports car performance.
- Low Exhaust Gas Emissions: The short exhaust paths also help maintain higher exhaust gas temperatures as they reach the catalytic converters. This promotes faster light-off of the catalytic converters, leading to reduced emissions, especially during cold starts.
Dry Sump Lubrication
Another pioneering feature of the AMG 4.0-liter V8 biturbo is its dry sump lubrication system, a technology typically reserved for racing cars and high-performance sports cars. Unlike conventional wet sump systems, dry sump lubrication employs a multi-stage oil pump and a separate oil reservoir. The benefits are profound:
- Lower Engine Installation: By eliminating the traditional oil pan at the bottom of the engine, the dry sump system allows for a significantly lower engine mounting position. In the AMG GT, this lowers the center of gravity by approximately 2.2 inches. A lower center of gravity is fundamental to enhancing a sports car’s handling, agility, and cornering capabilities.
- High Lateral Acceleration Capability: In high-performance driving, particularly during aggressive cornering, lateral G-forces can cause oil starvation in conventional wet sump systems as oil sloshes away from the oil pump pickup. Dry sump lubrication overcomes this issue by using multiple suction points to scavenge oil from the crankcase and cylinder heads, ensuring a constant and reliable oil supply even under extreme lateral loads experienced on the track. This guarantees optimal engine lubrication and prevents potential engine damage during spirited driving.
The M178 engine’s dry sump system is sophisticated, utilizing a suction pump, a pressure pump, and an external oil tank with a 12-liter capacity. The system circulates around 9 liters of oil, with the suction pump capable of extracting up to 250 liters of oil per minute. This efficient oil management contributes to both engine durability and performance.
Performance and Specifications: Unleashing Motorsport-Inspired Power
The AMG 4.0-liter V8 biturbo engine is engineered to deliver exhilarating performance, drawing inspiration from motorsport technology. It’s not just about peak numbers; it’s about the character of the power delivery and the overall driving experience.
The AMG M178 V8 engine at a glance:
| Feature | Specification |
|---|---|
| Cylinder Arrangement | V8 |
| Cylinder Angle | 90° |
| Valves per Cylinder | 4 |
| Displacement | 3982 cc |
| Bore x Stroke | 83.0 x 92.0 mm |
| Cylinder Spacing | 90 mm |
| Compression Ratio | 10.5 : 1 |
| Peak Output | 503 hp (375 kW) @ 6250 rpm |
| Output per Liter | 126.3 hp/liter (94.2 kW/liter) |
| Max. Torque | 479 lb-ft (650 Nm) @ 1750 – 4750 rpm |
| Torque per Liter | 120.4 lb-ft/liter |
| Maximum Engine Speed | 7200 rpm |
| Maximum Charge Pressure | 17.4 psi |
| Engine Weight (Dry) | 460 lbs (209 kg) |
Superior Power Delivery and Driving Dynamics
The performance characteristics of the AMG 4.0-liter V8 biturbo are meticulously tuned to offer a blend of raw power and refined driving dynamics. Key aspects include:
- Broad Torque Curve: The engine produces its peak torque of 479 lb-ft across a wide rev range, from 1750 to 4750 rpm. This flat torque curve ensures exceptional responsiveness and pulling power in everyday driving and during spirited acceleration.
- Motorsport-Inspired Performance: With 503 horsepower on tap, the engine delivers acceleration and speed figures befitting a high-performance sports car. The high-revving nature, with a redline of 7200 rpm, adds to the sporty character.
- Emotive AMG V8 Sound: AMG engines are renowned for their distinctive sound, and the 4.0-liter V8 biturbo is no exception. It produces a deep, resonant V8 rumble that is both thrilling and instantly recognizable, further enhancing the driving experience.
Technologically, the AMG 4.0-liter V8 shares similarities with the AMG 2.0-liter turbo four-cylinder engine found in models like the CLA 45 AMG and GLA 45 AMG. Both engines share the same bore-to-stroke ratio, contributing to their high-revving potential. The engine utilizes third-generation direct petrol injection with piezo injectors for precise fuel delivery, optimizing both power and efficiency.
Technical Deep Dive: Engineering Excellence
Beyond its headline features, the AMG 4.0-liter V8 biturbo is packed with advanced engineering details that contribute to its overall performance, efficiency, and durability.
NANOSLIDE Cylinder Bore Technology
The aluminum crankcase of the engine is manufactured using sand casting and features a closed deck design for maximum rigidity and minimal weight. The cylinder bores are treated with NANOSLIDE technology, a Daimler-patented process that creates a microscopically thin, exceptionally hard, and low-friction coating on the cylinder surfaces.
NANOSLIDE technology offers several key advantages:
- Reduced Friction: The ultra-smooth NANOSLIDE coating significantly reduces friction between the piston rings and cylinder walls. This minimizes energy losses, leading to improved fuel efficiency and reduced wear.
- Enhanced Durability: The coating is twice as hard as conventional cast-iron cylinder liners, making the cylinder bores highly resistant to wear and tear, contributing to the engine’s long-term durability.
- Weight Reduction: NANOSLIDE eliminates the need for separate cylinder liners, contributing to the engine’s lightweight design.
Daimler developed NANOSLIDE starting in 2000, and it has been used in over 200,000 engines since 2006, including the predecessor to the current AMG 4.0-liter biturbo V8. Its success and proven benefits have led to its adoption in demanding applications, including Mercedes-Benz Formula 1 V6 turbo engines since the 2014 season.
“Spectacle honing” is another precision manufacturing process used in the engine. This technique treats the cylinder liners mechanically after they are bolted into the engine block. A special jig mimicking spectacles is used in place of the cylinder head during honing. This accounts for and eliminates any cylinder distortion that might occur during final assembly, improving both durability and oil consumption.
Advanced Combustion and Direct Injection
The AMG 4.0-liter V8 biturbo employs direct petrol injection with spray-guided combustion, working in conjunction with biturbocharging to maximize thermodynamic efficiency. This results in optimized fuel consumption and reduced emissions.
- Piezo Injectors: Fast and precise piezo injectors spray fuel directly into the eight combustion chambers at high pressure. Multiple injections occur on demand to ensure a homogenous air-fuel mixture for efficient combustion.
- Variable Fuel Pressure: The fuel delivery is electronically controlled and fully variable, with fuel pressure ranging from 1450 to 2900 psi, allowing for precise fuel metering under all operating conditions.
Biturbocharging System and Response
The “hot inside V” turbocharger arrangement is central to the engine’s responsiveness and compact design.
- Optimized Airflow: The ‘hot inside V’ configuration ensures optimal fresh air supply to the turbochargers. Electronically controlled blow-off valves further enhance responsiveness.
- High Charge Pressure: The turbochargers generate a maximum charge pressure of 17.4 psi and can spin at up to 186,000 rpm, forcing 2.3 times more oxygen into the engine compared to a naturally aspirated engine.
- Emission Control: Two close-coupled firewall catalytic converters with thin-walled ceramic material, along with two underfloor metal catalytic converters, provide effective emission control.
Performance Exhaust System
The sound of an AMG V8 is integral to the driving experience. The AMG GT features a sports exhaust system with fully variable exhaust flaps, allowing the driver to tailor the engine’s sound character.
- Variable Exhaust Flaps: Exhaust flaps in the rear silencer are variably actuated based on driving mode, throttle input, and engine speed.
- Sound Profiles: At low loads and engine speeds, the flaps remain closed for a subdued, comfortable sound. During acceleration and at higher engine speeds, the flaps progressively open, unleashing the full, powerful AMG V8 roar. This system provides versatility, allowing for both relaxed cruising and an exhilarating, motorsport-inspired soundtrack.
Efficient Cooling System
Maintaining optimal temperatures is critical for engine performance and longevity, especially in a high-output turbocharged engine. The AMG 4.0-liter V8 biturbo features a sophisticated cooling system:
- Indirect Air/Water Intercooling: An indirect air-to-water intercooling system with a separate low-temperature water circuit cools the charge air. This ensures intake air temperatures remain consistently low, even under full load, maximizing power output.
- Cross-Flow Cooling and Three-Phase Thermostat: The engine coolant system uses efficient cross-flow cooling and a three-phase thermostat for rapid warm-up.
- External Engine Oil Cooler: An external engine oil cooler in the front apron helps manage oil temperatures. A two-stage controlled oil pump optimizes oil flow based on engine load and speed, improving fuel economy.
‘One Man, One Engine’: The Art of Hand-Built AMG Power
The AMG 4.0-liter V8 biturbo engine is meticulously hand-assembled in Affalterbach based on the “one man, one engine” principle. Highly skilled technicians build each engine from start to finish, adhering to the strictest quality standards.
This philosophy emphasizes:
- Craftsmanship: Each engine is built by a single, highly trained technician, ensuring meticulous attention to detail and quality.
- Accountability: The technician’s signature on the AMG engine plate serves as a personal commitment to quality and a mark of pride in their work.
- Motorsport Connection: This hand-built approach reflects the technology transfer from motorsport, ensuring that AMG engines embody the precision and performance demanded in racing environments, from Formula 1 to customer sports programs.
A Legacy of AMG V8 Engines: From Past to Present
Powerful V8 engines are deeply rooted in Mercedes-AMG’s history, dating back to the company’s inception in 1967. The 300 SEL 6.8 AMG “Red Pig” of 1971, with its modified M100 V8, famously took second place at the 24 Hours of Spa, marking AMG’s early motorsport success and showcasing the potential of AMG-tuned V8s.
Other significant AMG V8 engines throughout history include:
- M117 (5.6-liter V8): The first AMG eight-cylinder engine with four-valve technology, powering the legendary “Hammer” in the 1980s.
- M113 K (Supercharged 5.5-liter V8): A milestone engine from 2001, delivering immense power and torque in various AMG models.
- M155 (Supercharged 5.5-liter V8): Developed for the SLR McLaren, pushing supercharged V8 performance to new heights.
- M156 (Naturally Aspirated 6.3-liter V8): A high-revving, naturally aspirated masterpiece introduced in 2005, known for its thrilling sound and power delivery.
- M159 (6.3-liter V8): An evolution of the M156, exclusively for the SLS AMG, reaching even greater power outputs.
- M157 (5.5-liter V8 Biturbo): The predecessor to the M178, known for its efficiency and broad torque band.
The Mercedes-AMG 4.0-liter V8 biturbo engine builds upon this rich heritage, representing the pinnacle of AMG’s V8 engine technology. It combines decades of experience with cutting-edge innovations to deliver an engine that is not only powerful and efficient but also embodies the soul of AMG – “Driving Performance.”
In conclusion, the Mercedes-AMG 4.0-liter V8 biturbo is more than just an engine; it’s a statement of engineering excellence, a symbol of AMG’s unwavering commitment to performance, and a thrilling heart for some of the world’s most desirable sports cars. It sets a new standard for V8 engines in the 21st century, promising an exhilarating driving experience for generations to come.
