The 2021 Mercedes-AMG GT Black Series features the most powerful AMG V8 series engine of all time
For the new Mercedes-AMG GT Black Series, Affalterbach's engineers have raised the bar in the art of vehicle design. Share
This new super sports car perfectly embodies the brand’s rich tradition in motorsport, as well as its expertise in developing complete vehicles which impress in every respect. The result is an awe-inspiring vehicle with 720 hp from a Handcrafted AMG V8 engine with a flat-plane crankshaft, combined with active aerodynamics and a design stemming directly from the current AMG GT3 racing car.
At Mercedes-AMG, the Black Series has been synonymous with a very special type of car since 2006: uncompromisingly sporty, with an expressive design and the most direct technology transfer from motorsport to series production. Black Series models are exclusive automotive rarities. They are not developed to gather dust in collectors’ garages, but for high-speed use on race tracks, despite being approved for road usage. The AMG GT Black Series represents a new highlight in this tradition: It features the most powerful Mercedes-AMG V8 series engine of all time.
In order to redefine the super sports car, the engine specialists in Affalterbach have once again extensively redeveloped the tried-and-tested 4.0-liter V8 biturbo unit – despite it already being renowned for excellent drivability, power delivery and torque. The specifications were clear: Significantly more power than the previous flagship model of the AMG GT family, an even more agile throttle response, maximum torque – all of which meant that a radical change was needed in the form of a new, flat-plane crankshaft.
“The new GT Black Series is our latest automotive highlight and continues a tradition established in 2006. The sixth iteration of its kind is another AMG milestone and impressive proof of the incredible development expertise in Affalterbach. I am proud of the team who have created this unique super sports car, which now represents the absolute peak of our successful GT family. The performance, appearance and driving dynamics of the GT Black Series are second to none. This project was a fantastic end to my work at AMG, for which I am truly thankful,” says Tobias Moers, Chairman of the Board at Mercedes-AMG GmbH.
Distinctive V8 engine design
The design of a V8 engine gives designers plenty of room to play with in one key element: the crank arrangement on the crankshaft. This influences the characteristics of the engine. There are usually two variants in V8 engines: the ‘cross plane’ where the crankpins of the four pairs of cylinders are at 90-degree angles to each other, which AMG has used in all previous V8 engines, or the ‘flat-plane crankshaft’, where all crankpins are on the same plane with a 180-degree offset (‘flat-plane’).
If you look at the front of a cross-plane crankshaft, you will be able to identify the cross that gives it its name. The benefits of these crankshafts are superb smoothness and high torque at low rotational speeds. The characteristic sound is another hallmark feature of the cross-plane V8 engine. In order to make optimal use of the displacement and the performance potential in the 4.0-liter V8 biturbo engine, AMG engineers have essentially moved the exhaust side into the hot internal V of the two cylinder banks in the V8 engine.
Uniformly oscillating gas columns for even more power
Another way of increasing performance is by utilizing a flat-plane crankshaft. In the flat-plane V8 engine, it looks like an inline four-cylinder model – except for the wider crankpins, which have two connecting rods each in the V8. Ignition in the flat-plane V8 jumps from one cylinder bank to the next, which further improves the gas cycle. The characteristic firing order with a 180-degree crankshaft angle offset is 1-8-2-7 4-5-3-6. This creates uniformly oscillating gas columns in the exhaust tract and on the intake side, whose resonance can easily be used to increase performance. An even greater advantage is a more agile throttle response.
The most powerful V8 engine from Mercedes-AMG
Although the new GT Black Series engine is based on the AMG 4.0-liter V8 biturbo with dry sump lubrication, it has been given the new internal code of M178 LS2, due to its numerous modifications. It achieves 720 hp at 6,700-6,900 rpm and delivers a maximum torque of 590 lb-ft at 2,000-6,000 rpm. New camshafts and exhaust manifolds are adapted to the new firing order and further improve the gas cycle.
Both twin-scroll exhaust turbochargers are mounted in anti-friction bearings, as in the top-of-the-range four-door AMG GT Coupe, which optimizes their throttle response even further. However, in the GT Black Series, the turbochargers have been given a larger compressor wheel, meaning that both can deliver a total of 24.6 psi. By way of comparison: The figure is 19.6 psi for the AMG GT R. 7,000 rpm is not critical as a continuous speed, so the redline instead tops out at 7,200 rpm. The larger intercoolers guarantee they always keep the charge-air temperature within the best possible range. The unique aspects of the new engine are also reflected in the distinctive engine badge, which is rendered in black.
0-124 mph in under nine seconds
The new Handcrafted AMG engine in the GT Black Series gives it a completely unique character, which is not only reflected in the power delivery, but also in its very distinctive sound. The new engine also enables highly impressive driving performance: The Black Series shoots from 0 to 60 mph in 3.1 seconds, and to 124 mph (200 km/h) in under nine seconds. The top speed is 202 mph, although this is only sensible on closed-off racetracks.
