Mercedes-AMG has consistently pushed the boundaries of automotive performance, and at the heart of many of their exhilarating vehicles lies the potent “Benz Biturbo” engine technology. A prime example of this engineering prowess is the AMG 4.0-liter V8 biturbo, a masterpiece of modern engine design that perfectly embodies the brand’s commitment to “Driving Performance.” This innovative eight-cylinder power unit is not just about raw power; it’s a symphony of sublime power delivery, intelligent lightweight construction, remarkable efficiency, and a nod towards environmental consciousness. Generating a peak output of up to 503 horsepower and a staggering 479 lb-ft of torque, this AMG V8 engine delivers a driving experience directly inspired by the high-octane world of motorsport. This new sports car engine proudly continues the legacy of powerful V8s at AMG, a tradition that began in 1967 with the iconic M100 engine in the legendary 300 SEL 6.8 AMG racing car, and it sets new benchmarks for future engine technology.
For decades, powerful V8 engines have been a defining characteristic of AMG, Mercedes-Benz’s high-performance division. The Affalterbach facility is renowned for producing innovative and thrilling high-performance engines. Significantly, Mercedes-AMG GmbH takes complete responsibility for both the development and the meticulous production of these engines, ensuring unparalleled quality and performance.
Tobias Moers, Chairman of the Board of Management of Mercedes-AMG GmbH, aptly stated, “V8 engines are fundamental to the AMG philosophy and the brand’s dedication to ‘Driving Performance’. The V8 biturbo engine designed for our new GT models is guaranteed to thrill our customers!”
Adding to this, Christian Enderle, Head of Engine and Powertrain Development at Mercedes-AMG, commented, “With the new AMG 4.0-liter V8 biturbo, we are unveiling an exciting and formidable sports car engine. Through numerous innovative measures, this engine also marks a significant advancement in terms of efficiency.”
Revolutionary ‘Hot Inside V’ Configuration and Dry Sump Lubrication
The AMG V8 “benz biturbo” engine distinguishes itself with a groundbreaking design: its two turbochargers are not positioned on the outer sides of the cylinder banks, but rather nestled within the V configuration itself – a layout experts refer to as the ‘hot inside V’. This ingenious configuration offers several key advantages. Firstly, it results in a significantly more compact engine design, contributing to better overall vehicle packaging and weight distribution. Secondly, it drastically improves engine responsiveness, as the shorter exhaust paths to the turbochargers minimize lag. Lastly, this design aids in reducing exhaust gas emissions by optimizing the catalytic converter’s placement and warm-up time. Furthermore, the engine incorporates dry sump lubrication, a technology typically found in racing cars. This system allows for a lower engine installation, which in turn lowers the vehicle’s center of gravity. A lower center of gravity is crucial for enhanced handling and forms the foundation for achieving higher lateral acceleration in performance vehicles. The M178, AMG’s internal designation for this engine, proudly holds the distinction of being the world’s first sports car engine to combine the ‘hot inside V’ configuration with dry sump lubrication. Adding to its technological prowess, the new AMG V8 engine boasts a dry weight of just 460 lbs, making it the lightest engine in its competitive class.
Image alt: Close-up of the Mercedes-AMG 4.0-liter V8 biturbo engine showcasing its compact design and ‘hot inside V’ configuration.
AMG M178 V8 Engine: Technical Specifications
| 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 | 503hp (375 kW) @ 6250 rpm |
| Specific Output | 126.3 hp/liter (94.2 kW/liter) |
| Maximum Torque | 479 lb-ft @ 1750 – 4750 rpm |
| Specific Torque | 120.4 lb-ft/liter |
| Maximum Engine Speed | 7200 rpm |
| Maximum Charge Pressure | 17.4psi |
| Engine Weight (Dry) | 460 lbs |
Superior Power and Motorsport DNA
The AMG M178 “benz biturbo” engine is engineered to deliver exceptional power in a refined and exhilarating manner, embodying motorsport-inspired performance characteristics. It produces a distinctive and emotionally resonant AMG V8 engine sound, coupled with instantaneous throttle response and robust pulling power across the rev range. The engine’s torque curve is meticulously tuned for optimal driveability: the peak torque of 479 lb-ft is readily available across a broad spectrum from 1750 to 4750 rpm. This wide torque plateau ensures effortless acceleration and responsiveness in everyday driving and spirited performance scenarios.
With a displacement of 3982 cc, the V8 shares technological similarities with the AMG 2.0-liter turbo engine found in models like the CLA45 AMG and GLA45 AMG. The 2.0-liter turbo is recognized as the most powerful series-production four-cylinder engine globally, highlighting AMG’s expertise in forced induction. Both AMG engines share the same bore-to-stroke ratio, a design choice that promotes high-revving capabilities and contributes to their dynamic character. The fuel-air mixture formation in the 4.0-liter V8 is managed by third-generation direct petrol injection incorporating piezo injectors. This advanced system ensures highly precise fuel delivery, contributing to the engine’s impressive efficiency and economical operation for a high-performance “benz biturbo” V8.
NANOSLIDE® Cylinder Bore Technology
The engine’s aluminum crankcase is manufactured using sand casting technology and features a closed deck design. This construction method provides exceptional structural rigidity while minimizing weight. The cylinder bores are treated with NANOSLIDE® technology, a Daimler-developed innovation that renders the surfaces twice as hard as conventional cast-iron linings.
Image alt: Microscopic view of a NANOSLIDE cylinder bore surface, highlighting its ultra-fine and wear-resistant structure.
Daimler pioneered NANOSLIDE® technology starting in 2000, and it has been successfully implemented in over 200,000 engines since 2006. Interestingly, the first engine to utilize NANOSLIDE® was also an AMG V8, the highly successful predecessor to this new 4.0-liter “benz biturbo.” The application of this award-winning technology has continually expanded, and since the 2014 racing season, it has even been incorporated into the Mercedes F1 V6 turbo engine, showcasing its performance benefits in the most demanding environments.
Another friction-reducing and consumption-optimizing technique employed is ‘spectacle honing’. In this sophisticated process, the cylinder liners undergo their mechanical surface treatment after being bolted into the engine block. A specialized jig, resembling spectacles, is attached to the crankcase in place of the cylinder head during honing. This ensures that any cylinder distortion that might occur during final assembly is accounted for and eliminated during the honing process. This meticulous approach enhances both engine durability and reduces oil consumption. The AMG V8 also features lightweight forged aluminum pistons engineered for high strength. A low-friction piston ring package further minimizes both fuel and oil consumption.
Dry Sump Lubrication for Enhanced Dynamics
The adoption of dry sump lubrication eliminates the need for a conventional oil pan. This allows the engine to be mounted lower in the vehicle’s chassis, effectively lowering the center of gravity by 2.2 inches. This lower center of gravity significantly benefits a sports car designed for exceptional lateral dynamics and agile handling. Beyond improved agility, dry sump lubrication ensures consistent and direct oil extraction from the crankcases, providing optimal engine lubrication even under extreme conditions, such as high-speed cornering and significant lateral loads encountered on a track.
The M178 dry sump lubrication system utilizes a suction pump, a pressure pump, and an external oil tank with a substantial 12-liter (12.8 quarts) capacity. The entire system circulates nine liters of engine oil. The oil suction pump extracts oil directly from the crankcases, cylinder heads, and valve body assembly, delivering it to the external oil tank at an impressive rate of up to 250 liters (264 quarts) per minute. The lubricant resides in the external tank for a mere five seconds before being recirculated back into the high-performance engine. This efficient oil scavenging enhances engine efficiency. The pressure oil pump’s on-demand control system dynamically adjusts to engine rpm, temperature, and load characteristics stored in the engine control unit, optimizing lubrication and minimizing parasitic losses. The use of plastic for the oil pan bottom section and the oil tank demonstrates a commitment to lightweight construction throughout the engine design.
Advanced Cylinder Heads and Valve Train
The cylinder heads of the AMG 4.0-liter V8 “benz biturbo” engine are crafted from a zirconium alloy, chosen for its exceptional temperature resistance and thermal conductivity. Four overhead camshafts control a total of 32 valves. Camshaft adjustment on both the intake and exhaust sides optimizes engine response and fine-tunes the gas cycle for each operating point. Optimized valve springs and a low-friction valve train with cam followers contribute to further fuel efficiency gains.
Direct Injection for Efficiency and Performance
The combination of “benz biturbo” charging and direct petrol injection with spray-guided combustion significantly enhances thermodynamic efficiency, leading to reduced fuel consumption and lower exhaust emissions. High-speed and highly precise piezo injectors inject fuel at high pressure directly into the eight combustion chambers. Multiple injections occur as needed, ensuring a homogenous fuel-air mixture for optimal combustion. The fuel delivery is electronically controlled and fully variable, operating at fuel pressures between 1450psi and 2900psi.
‘Hot Inside V’ Biturbocharging System
Unlike traditional configurations, the two exhaust gas turbochargers in the new M178 engine are positioned within the ‘hot inside V’ configuration, rather than externally to the cylinder banks. This innovative layout offers several benefits. It makes the V8 engine significantly more compact, contributing to optimal weight distribution between the front and rear axles and enabling a lower engine installation height. The ‘hot inside V’ design also optimizes the flow of fresh air to both turbochargers. Electronically controlled blow-off valves ensure exceptionally quick and direct engine response. The maximum charge pressure reaches 17.4psi, and the turbochargers can spin at speeds up to 186,000 revolutions per minute. For combustion, the turbocharged engine forces 2.3 times more oxygen atoms into the cylinders compared to a naturally aspirated engine. Two firewall catalytic converters made of thin-walled ceramic material are positioned close to the exhaust gas turbochargers for rapid response. Combined with two metal underfloor catalytic converters, the M178 achieves effective emission control.
Sports Exhaust System with Variable Flaps
Emotion, a captivating sound, and instant recognition are key objectives in AMG engine development. The new GT features a sports exhaust system equipped with fully variable exhaust flaps. This innovative system gives the driver the ability to modulate the engine’s sound character. Depending on the selected driving mode, the driver can experience the AMG V8 in a comfort-focused setting, ideal for relaxed long journeys, or unleash a more emotive, motorsport-inspired roar. The M178 engine possesses its own unique tonal signature, clearly identifying it as a member of the AMG family while also distinguishing it from other high-performance vehicles.
Image alt: Rear view of the Mercedes-AMG GT showcasing its sports exhaust system with quad exhaust outlets, emphasizing the vehicle’s performance-oriented design.
An exhaust flap is located on each side of the rear silencer and is variably actuated based on a logic-controlled system that takes into account the transmission mode, driver’s power demand, and engine speed. At low loads and engine speeds, the flaps remain closed. This forces the exhaust gases to travel a longer path through an additional damping element, resulting in a pleasantly subdued engine sound and effective suppression of unwanted frequencies. When the driver accelerates, the flaps progressively open, allowing some exhaust gases to still take the longer, acoustically dampened route, while the majority flows through the shorter path. Under full load at higher engine speeds, both flaps are fully opened, allowing occupants to fully appreciate the powerful and characteristic AMG V8 sound, leaving no doubt about the 503hp “benz biturbo” engine’s performance potential.
Efficient Cooling Systems
For consistent peak power output even in high ambient temperatures, Mercedes-AMG employs indirect air-to-water intercooling. The charge air cooler has a separate, low-temperature water circuit. Thanks to an optimized flow profile through the intercooler, the maximum intake air temperature is maintained at 356 degrees Fahrenheit. The low-temperature cooler and its dedicated water circuit ensure that the intake air compressed by the turbochargers is effectively cooled before entering the combustion chambers, maintaining a consistently low intake temperature even under sustained full-load conditions. A large radiator at the front of the car ensures controlled cooling of the water circulating in the low-temperature circuit. Extremely short charge-air ducting contributes to optimal engine responsiveness.
The engine coolant system utilizes a highly efficient cross-flow principle and a three-phase thermostat for faster coolant warm-up. The water pump is driven by a timing chain rather than a conventional poly-V-belt, simplifying the belt drive system and reducing clamping force. This results in reduced drive power losses. With a rated flow of 111 gallons per minute, the water pump can move the equivalent of more than two full bathtubs of water every minute.
An external engine oil cooler, located in the front apron of the Mercedes-AMG GT, assists in managing the V8 engine’s thermal load. A two-stage, controlled oil pump circulates the engine oil, varying the flow rate based on load and engine speed requirements to enhance fuel economy. At high engine speeds, more than 1.0 quart of engine oil per second flows through the oil lines and ducts. To minimize weight, numerous oil and water lines are made of aluminum.
Further sophisticated solutions are integrated into the engine’s peripheral systems:
- Dedicated cooling-air flow for the exhaust gas turbochargers under high thermal loads.
- Active engine mounts to balance excellent lateral dynamics with ride comfort.
- Efficiently powered auxiliary units driven by two short, low-friction belts with four grooves. Intelligent positioning of auxiliary units virtually neutralizes belt forces on the crankshaft.
- A dual-mass flywheel with a centrifugal pendulum prevents torsional vibration in the driveline for a smoother ride.
- ECO start/stop function and alternator management to further enhance fuel efficiency.
Rigorous Testing and “One Man, One Engine” Philosophy
In Affalterbach, nine state-of-the-art test stations are used to dynamically test AMG engines with outputs exceeding 630hp and 738 lb-ft of torque. These test facilities can simulate a wide spectrum of road and environmental conditions, replicating virtually any conceivable driving scenario. From cold starts and hot starts to mountain passes, stop-and-go traffic, and high-speed laps on the Nürburgring Nordschleife, the engines are pushed to their limits. Even varying intake air temperatures and densities can be precisely controlled by computer.
The comprehensive bench testing program aims to validate the performance of all engine components, including peripheral units. All measurement data collected from engine testing is systematically compared and evaluated using repeatable test methods. Functional tests are complemented by rigorous endurance testing. To ensure the highest quality standards throughout their operational life, new AMG engines undergo thousands of hours of endurance testing.
Simultaneously, the first test engines undergo intensive real-world trials. The standardized test program at Mercedes-AMG encompasses all climatic zones and diverse route profiles, from the extreme cold of northern Sweden to the scorching heat of Death Valley (USA), and from high-speed circuits in Nardo (Italy) and Papenburg to stop-and-go city traffic during rush hour. This exhaustive program places the highest demands on the everyday practicality, reliability, and long-term durability of each new generation of AMG “benz biturbo” engines.
Image alt: Interior view of the AMG engine assembly shop in Affalterbach, highlighting the “one man, one engine” principle with a technician assembling a V8 engine by hand.
The AMG 4.0-liter V8 “benz biturbo” engine is meticulously hand-assembled in Affalterbach following the renowned “one man, one engine” principle. In the AMG engine shop, highly skilled technicians assemble these high-performance engines by hand, adhering to the strictest quality standards. The technician’s signature on the AMG engine plate serves as a testament to this exclusive engine production method and signifies the highest levels of quality and technology transfer from motorsport – from Formula 1 and DTM racing to customer sport activities in the SLS AMG GT3.
A Legacy of Powerful AMG V8 Engines
Powerful eight-cylinder engines are deeply ingrained in the history of Mercedes-AMG. Established in 1967, the company first gained prominence with the 300 SEL 6.8 AMG, which achieved a remarkable second place overall at the 24-hour race in Spa-Francorchamps (Belgium) in 1971, securing a class victory. This AMG racing sedan was based on the Mercedes-Benz 300 SEL 6.3, powered by the M100 V8 engine. Producing 246hp at 4000 rpm and reaching a top speed of 136mph, this luxury sedan was the fastest production car in Germany at the time. Classic tuning and an enlarged displacement, increased from 6330 to 6835 cc, boosted the output to 422hp at 5500 rpm and torque from 368 to 448 lb-ft.
Another significant engine in AMG’s history was the M117, their first eight-cylinder unit featuring a four-valve-per-cylinder design. With a 5.6-liter displacement, 355hp, and 376 lb-ft of torque, this V8 propelled the 300 CE 5.6 AMG to a top speed of 188mph. In 1987, this coupe became the fastest German production car, earning the revered nickname “The Hammer” among American AMG enthusiasts.
The supercharged AMG 5.5-liter V8 of 2001 marked another milestone in AMG engine development. The M113 K produced up to 574hp and 590 lb-ft of torque. The supercharged AMG 5.5-liter V8 in the SLR McLaren from 2003 was even more potent – the M155 generated up to 641hp and 604 lb-ft of torque.
2005 witnessed the debut of the naturally aspirated, high-revving AMG 6.3-liter V8 engine, known as the M156. It delivered up to 517hp and 465 lb-ft of torque, depending on the model. Exclusively reserved for the SLS AMG, the also 6.3-liter M159 engine produced a maximum output of 563hp and 479 lb-ft of torque. In the SLS AMG Coupe Black Series, the M159 reached an impressive 622hp.
The AMG 5.5-liter V8 “benz biturbo” M157 engine delivers between 517hp and 577hp, depending on the model, with a maximum torque range of 516 to 664 lb-ft. The M157 is recognized as one of the most efficient engines in its output and displacement class. The AMG 4.0-liter V8 “benz biturbo” continues this impressive lineage, representing the latest chapter in AMG’s ongoing pursuit of performance excellence and technological innovation in “benz biturbo” engine design.
