The Audi S8 is the ultimate expression of luxury, performance and practical business-sedan sense or, as Audi V8 engine head Jurgen Konigstedt said, “It is the most powerful sedan in our history.” It's powerful despite the loss of two cylinders, even.
Gone is the Lamborghini-derived V10--which was kind of cool, having a Lamborghini under the hood of your executive sedan--replaced by a more powerful, more fuel-efficient 4.0-liter twin-turbo V8. Thanks to bigger twin-scroll turbos, lower compression ratio and unique cams it makes 520 hp at 6,000 rpm and 481 lb-ft of torque on a plateau that runs from 1,500 to 5,500 revs. Both of the exhaust manifolds and the two turbochargers sit on top, in between the banks of the 90-degree V8, while the intakes come from outside the Vee.
The packaging of the engine is impressive, from its wide, nearly flat oil pan all the way up to the cylinder deactivating camshafts that turn it from a V8 to a V4 to get better fuel mileage. Konigstedt says it's shorter than a V6. "The compactest V8 in the world!" This thing should be in airplanes.
Power goes through an eight-speed tiptronic transmission (not a dual clutch as on the S6 and S7) and thence to all four wheels through Audi's quattro all-wheel drive. The S8 also gets Audi's sport differential.