AMG 4.0-litre V8 biturbo engine: More power, more torque, faster response 13.12.2016: Mercedes-AMG GT R: Racing car with a permit for operation on public roads The heart of the new high-performance athlete is pumping

Mercedes-AMG GT R: Racing car with a permit for operation on public roads





The heart of the new high-performance athlete is pumping stronger than ever: the AMG 4.0-litre twin-turbo engine in the AMG GT R has an output of 430 kW (585 hp), which is 55 kW (75 hp) more than the previous top-of-the-range engine in the AMG GT S. The peak torque of 700 Nm is available between 1900 and 5500 rpm.


The increase in performance was achieved with the help of new turbochargers with modified compressor machining, smaller wastegate aneroid capsule and sharpened engine mapping.



 The boost pressure supplied by the turbochargers has been increased from 1.2 bar in the AMG GT to 1.35 bar. In addition, the exhaust ports have been optimised and the compression ratio modified. The entire combustion process has been adapted.



A correspondingly modified application of the accelerator characteristics, charge-pressure build-up and transmission parameters ensures that the engine responds to load changes even more spontaneously and that gear changes are effected with even greater speed.



The fact that the two-mass flywheel is 0.7 kilograms lighter than its counterpart in the AMG GT S likewise contributes to the highly agile impression.

Linear output with powerful thrust




The eight-cylinder unit thrills with its spontaneous response, precisely measured power output and linear power delivery with powerful thrust in all engine speed ranges, all of which makes the car far easier to control when driving at the limit.



 To make this possible, the sophisticated engine control electronics also take into account the current driving status and control the accelerator characteristics as a function of the occurring lateral forces also.




The AMG 4.0-litre V8 comes with well-proven twin turbocharging, with the two chargers not located outside on the cylinder banks, but rather between them in the V of the cylinders.



 The advantages of the "hot inner V" are a compact engine design, spontaneous response from the turbochargers and low exhaust gas emissions thanks to optimum air flow for the close-coupled catalytic converters.



This basic principle of the new AMG V8 family has been further optimised for the AMG GT R, enabling a further improvement in performance.



The maximum charge pressure is 1.35 bar; the turbochargers have a maximum speed of 186,000 revolutions per minute.



For optimum power output even when outside temperatures are high, Mercedes-AMG uses indirect air-to-water intercooling. With optimum flow of air and water, the intercoolers have a separate, two-stage low-temperature water circuit.



The first cooler stage involves two parallel coolers in the left and right wheel arch. Together with the large radiator at the front of the vehicle as a second radiator stage, the system is even more effective than in the AMG GT S.



The downstream water-cooled intercoolers ensure that the charge air compressed and heated by the turbochargers is cooled effectively prior to entering the combustion chambers. It therefore remains at a constantly low level even under full load. Extremely short charge-air ducting makes for optimum responsiveness.







Multiple injection with piezo injectors


The combination of twin turbochargers and direct petrol injection with spray-guided combustion increases thermodynamic efficiency and output. Particularly fast and precise piezo injectors spray the fuel at high pressure into the 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.



The aluminium crankcase is produced using sand casting technology and features a closed-deck design. This ensures extreme strength while keeping the weight as low as possible, and allows high injection pressures of up to 140 bar.



The NANOSLIDE® coating of the cylinder liners is also used in the Formula One engines of MERCEDES-AMG PETRONAS. It is far harder than conventional grey cast-iron liners and therefore less susceptible to wear. In addition to this, its reduced friction in combination with the aluminium forged pistons helps to increase efficiency.



Four overhead camshafts control a total of 32 valves. Camshaft adjustment on the intake and exhaust side enables an excellent throttle response and optimises the gas cycle for each operating point.



The dry sump lubrication also ensures the oil supply even with high lateral forces and allows the engine to be installed lower, thus moving the centre of gravity closer to the road and forming the basis for high lateral acceleration.




The engine for the AMG GT R is also fitted by hand in the hand-finishing section of AMG's production plant in Affalterbach based on the "One Man - One Engine" philosophy.



This means that each engine is assembled by a highly qualified engine builder who applies the strictest quality standards. This engineer is responsible for everything from installing the crankshaft in the engine block and assembling the camshafts to wiring the engine and filling it with engine oil ‑ as clearly evidenced by the signature on the AMG engine badge.





Pure sound: the AMG performance sports exhaust system


The specially developed exhaust system not only delivers genuine racing car sound, it also saves around six kilograms of weight compared with the AMG GT S thanks to the use of titanium for the rear silencer and thin-walled stainless steel for the front section of the exhaust system.




With its special, hexagonal form, the large tailpipe tip centred in the rear apron emphasises the car's motor-racing character. Two more tailpipes are located on the left and right in the diffuser.



Their tips are sheathed in carbon fibre like in motorsport to protect the diffuser against high exhaust temperatures. The exhaust system features two infinitely variable exhaust flaps as standard, which have a direct influence on the sound of the AMG GT R.



The exhaust flaps open and close depending on the selected AMG DRIVE SELECT mode, although they can also be controlled individually using a separate button in the AMG DRIVE UNIT.



In the "Comfort" and "Sport" settings, the low-frequency sound typical of a V8 is designed for comfort. In "Sport Plus" and "RACE" modes, meanwhile, the sound composition is far more emotive.






Koert Groeneveld, Birgit Zaiser - photos Mercedes