News of April 11, 2001
Audi A8 L 6.0 quattro - The world’s most powerful production saloon: Twelve cylinders for the A8
Audi A8 L 6.0 quattro
Seventy years after the legendary Horch Type 670 made its debut, Audi is adding a new chapter to the story of high-class twelve-cylinder cars. The launching of the A8 L 6.0 quattro marks the appearance of a vehicle full of superlatives – the most powerful series-production saloon in the world. This luxury saloon is powered by an aluminium twelve-cylinder engine with a displacement of six litres, which develops 309 kW (420 bhp). This engine thus qualifies as the most powerful production twelve-cylinder engine ever to be found in a saloon car worldwide. And it also redefines the standard in terms of torque: the new Audi engine produces 550 Nm – this also surpasses any other saloon in the exclusive twelve-cylinder league.
The A8 L 6.0 quattro requires less than 5.8 seconds to sprint from 0 to 100 km/h, and it accelerates from 0 to 200 in a mere 20 seconds. The most powerful German twelve-cylinder production car reaches its electronically governed top speed of 250 km/h after scarcely 38 seconds. The most impressive thing about it is just how spontaneously the 6-litre engine translates every command issued at the throttle into acceleration, and just how smoothly it revs up to the rated speed of 6000 rpm.
At the same time more than 90 percent of the engine’s peak torque is available at just 1800 rpm; the ideal basis for supreme pulling power in every velocity range. The torque characteristic of this large-capacity naturally aspirated engine is without comparison.
The five-speed automatic transmission with tiptronic function makes sure that exactly the right amount of power is always available. And it additionally offers the driver the chance to intervene actively in the tiptronic gearshift gate.
Audi is the only manufacturer to use a twelve-cylinder engine in the form of a double ”V” or ”W” in series production. This design principle has one inestimable advantage: despite the larger number of cylinder units, and despite a clearly higher displacement, the W12 is as compact as the Audi 4.2 V8 engine, for example, and thus has much smaller dimensions than a conventional V12 engine.
This engine can only be combined with quattro four-wheel drive thanks to its unusually short length of 513 millimetres together with a width of 690 millimetres. All other twelve-cylinder engines installed at the front of the car can only drive the rear wheels – in this case there is not enough space under the bonnet for additional drive components.
Another advantage of this compact design – together with the choice of the light metals aluminium and magnesium – is the very low weight of the Audi twelve-cylinder engine, at 245 kg. And this in turn helps to produce an unbeatably low total vehicle weight of 1980 kilograms, lighter than any of its competitors.
A glance at the engine’s cylinder blocks shows that two ultra-compact inline V6 units are combined to produce a single engine. Each of the two blocks contains six cylinders at an angle of 15 degrees. This space-saving design concept produces an ideal synthesis of the very narrow dimensions of an inline engine and the compact length of a V engine.
The W12 engine for the A8 6.0 is now a combination of two of these units into a double V twelve-cylinder arrangement, at an angle of 72 degrees. The advantage is that the height of the engine is considerably less than that of a ”genuine” W12 with three cylinder banks, which means that the aerodynamically beneficial, flat silhouette of the A8's front end can remain unchanged.
As a gesture of respect to its particularly high performance, Audi's W12 engine has dry sump lubrication, which is usually only used on sports cars. The advantage of this is that it allows an optimum supply of oil to the engine even at high levels of longitudinal and lateral acceleration.
Double overhead camshafts per cylinder bank are responsible for the valve gear. The camshafts can be adjusted variably – by 52 degrees at the inlet valves and 22 degrees at the exhaust valves – which means that the optimum valve timing can be realised across the entire engine-speed range. It is thus possible to achieve good idle-speed quality, low crude emissions and ample torque across the speed range.
A handful of characteristic features suffice to distinguish the twelve-cylinder version of the V8 visually: viewed from the front, these include the distinctive radiator grille which has vertical bars in polished stainless steel. ”W12” emblems are located on the radiator grille, on the side rubbing strips and inside the car, above the glove box. At the rear of the car, the model inscription A8 L 6.0 quattro and the original design of the twin tailpipes indicate that you are looking at the flagship of the Audi model range. 18-inch forged aluminium wheels of 10-hole design and with 245/55 ZR 18 tyres give the vehicle a sumptuous appearance and point to its dynamic potential.
(April 10, 2001)