Another big displacement normally aspirated engine bites the dust – this time it’s the normally aspirated 5.2 litre V10 FSI engine found in models like the Audi S6 and S8.

Audi will be replacing it with a new twin turbocharged 4.0 litre V8, making 420 PS and 550Nm of torque from as low as 1,400rpm all the way to 5,300rpm. This tune of the engine will be installed in the S6 and the S7. This engine is mated to a 7-speed S-Tronic dual clutch transmission. The S6 and S7 also comes with adaptive air suspension to improve the cars’ versatility in providing both comfort and handling.

In the S8, the same 4.0 litre twin turbo V8 is tuned to produce more power – 520 PS and 650Nm of torque from between 1,700rpm to 5,500rpm. This should be an absolutely cracker to drive! In the S8, the engine is mated to a regular automatic transmission instead of a dual clutch, which should provide a smoother drive. The auto has a total of 8 gears.

Other than your usual direct injection and turbocharger technology, the new 4.0 litre V8 also has cylinder deactivation where four cylinders can be shut off under part load to conserve fuel. To keep the engine sounding good under the cylinder shut-off mode, Audi uses Active Noise Cancellation where four microphones integrated into the headlining record the noise in the cabin and cancels out any intrusive sound elements using an anti phase broadcast through the car’s speaker system.

I wonder if Audi will extend the use of this new engine to the Audi R8 as well. Will Audi put this new 4.0 litre twin turbo V8 into the Audi R8 V10′s engine bay?

These new range of Audi S cars will be exhibited to the public for the first time at the 2011 Frankfurt Motor Show. This year’s Frankfurt show looks like it’s going to be seriously busy – it’s going to keep us on our toes for sure! Enjoy a small gallery after the jump.