Powerful, innovative and efficient
Mercedes-AMG presents a new technological masterpiece: the AMG 4.0-litre V8 biturbo engine is a new development at the sporting heart of the new Mercedes-AMG GT car. This innovative eight-cylinder unit stands out for its sublime power delivery, the purposeful lightweight construction, as well as its high efficiency and environmental compatibility. With peak power of up to 375 kW (510 hp) and maximum torque of up to 650 Nm (479 lb-ft) the new AMG V8 delivers motorsport-inspired performance. The new sports car engine follows in an impressive V8 tradition that started in 1967 with the M100 in the legendary 300 SEL 6.8 AMG racing car and continues with trendsetting features of the future.
Powerful V8 engines have long been a core competence at AMG, the performance brand from Mercedes-Benz. Innovative and exciting high-performance engines come out of the location in Affalterbach. On this occasion, Mercedes-AMG GmbH is entirely responsible for both development and production.
Tobias Moers, Chairman of the Board of Management of Mercedes-AMG GmbH: “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: “The new AMG 4.0-litre 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.”
The new AMG V8 engine has two turbochargers which are not mounted on the outside of the cylinder banks but rather inside the V configuration – experts call it a ‘hot inside V.’ The benefits are a compact engine design, an optimum response and low exhaust gas emissions. Dry sump lubrication allows the engine to be installed lower, which moves the centre of gravity closer to the road and forms the basis for high lateral acceleration. The M178 (in-house designation) from AMG is thus the world’s first sports car engine with hot inside V and dry sump lubrication. With a dry weight of 209 kg (461 lbs) the new AMG V8 is also the lightest engine in its competitive segment.
Superior power delivery and motorsport-inspired performance
As the latest member of the Mercedes-Benz BlueDIRECT engine family, the AMG M178 stands out for its superior power delivery and motorsport-inspired performance. It boasts an emotive and unmistakable AMG V8 engine sound, along with an immediate response and high pulling power. The torque curve is synonymous with good driveability: the peak of 650 Nm (479 lb-ft) is available in the broad range from 1750 to 4750 rpm.
With a displacement of 3982 cc, in terms of technology the V8 is closely related to the AMG 2.0-litre turbo engine in the A 45 AMG, CLA 45 AMG and GLA 45 AMG, which is currently the most powerful, series-production four-cylinder engine in the world. Both AMG engines have the same bore/stroke ratio, guaranteeing high revving ability. Mixture formation comes courtesy of third-generation direct petrol injection with piezo injectors. The highly efficient and economical AMG 4.0-litre, V8 biturbo engine meets the Euro 6 emissions standard and the maximum particulate emissions level that takes effect in 2016.
The aluminium crankcase is produced using sand casting technology and features a closed deck design. This ensures extreme strength whilst keeping the weight as low as possible, and enables high injection pressures of up to 130 bar (1885 psi). The cylinder bore surfaces feature NANOSLIDE® technology which makes them twice as hard as conventional cast-iron linings.
NANOSLIDE® was developed by Daimler starting in the year 2000 and has so far been used in over 200,000 engines since 2006. The first unit with NANOSLIDE® technology was likewise an AMG V8: the extremely successful predecessor to the new AMG 4.0-litre biturbo. The application scope for this multi-award-winning technology has been continually widened. Since the start of the 2014 race season it is also being deployed in the new Mercedes F1 V6 turbo engine.
‘Spectacle honing’ is another measure to reduce friction and therefore consumption: in this complex process, the cylinder liners receive their mechanical surface treatment when already bolted in place. A jig resembling spectacles is bolted to the crankcase in place of the cylinder head mounted later. Any cylinder warpage that might occur during final assembly is therefore taken into account or eliminated as the cylinder liners are honed. This has advantages in terms of both durability and oil consumption. The new AMG V8 has forged aluminium pistons featuring a lightweight design and high strength. A low-friction piston ring package reduces fuel and oil consumption.
Thanks to the use of dry sump lubrication, a conventional oil pan is redundant. Already installed low down, the engine could thus be dropped by a further 55 mm (2.1 in). This lowers the vehicle’s centre of gravity, which is ideal for a sports car with extremely high lateral dynamics. In addition to improved agility, dry sump lubrication ensures direct oil extraction from the crankcases for optimal engine lubrication, even at high speeds on bends.
In the M178, dry sump lubrication deploys a suction pump, a pressure pump and an external oil tank with a capacity of 12 litres. The system circulates nine litres of engine oil in total. The oil suction pump extracts oil directly from the crankcases, cylinder heads and valve body assembly and delivers it to the external oil tank at a pump output of up to 250 litres (66 US gal) per minute. Lubricant remains there for just five seconds before being pumped back around the high-performance engine. Efficient engine oil suction improves engine efficiency further. On-demand control of the pressure oil pump takes into account the engine rpm, temperature and load characteristics stored by the control unit. Made of plastic, the oil pan bottom section and oil tank are proof of a commitment to lightweight construction.
Cylinder heads with zirconium alloy
The cylinder heads in the AMG 4.0-litre, V8 biturbo engine are made of a zirconium alloy for maximum temperature resistance and thermal conductivity. Four overhead camshafts control a total of 32 valves. Camshaft adjustment on the inlet and outlet side enables an excellent response and optimises the gas cycle for each operating point. Optimised valve springs and the low-friction valve gear with cam followers deliver further fuel savings.
Direct injection with spray-guided combustion
A combination of biturbocharging and direct petrol injection with spray-guided combustion increases thermodynamic efficiency, thereby reducing fuel consumption and exhaust gas emissions. Particularly fast and precise piezo injectors spray the fuel at high pressure into eight combustion chambers. Multiple injection occurs on-demand, ensuring a homogeneous fuel/air mixture. The delivery of fuel is electronically controlled and fully variable for a fuel pressure between 100 and 200 bar (1450 and 2900 psi).
Biturbocharging with ‘hot inside V’
Unlike the previously conventional approach, both exhaust gas turbochargers in the new M178 are located inside the ‘hot inside V’ configuration rather than on the outside of the cylinder banks. The advantages of this layout are that the V8 engine is considerably more compact, which enables optimum weight distribution between the front and rear axle, as well as the low installation position. The ‘hot inside V’ also optimises the supply of fresh air to both exhaust gas turbochargers. Electronically controlled blow-off valves ensure a very immediate and direct response. The maximum charge pressure is 1.2 bar; the turbochargers have a maximum speed of 186,000 revolutions per minute. For combustion purposes, 2.3 times more oxygen atoms are pressed into the turbocharged engine as would be the case in a naturally aspirated engine. The two firewall catalytic converters in thin-walled ceramic material positioned down from the exhaust gas turbochargers respond very quickly due to their close-coupled configuration. In conjunction with two metal, underfloor catalytic converters, the M178 delivers effective emission control.