At this year’s Frankfurt Motor Show, Audi will unveil four new S performance models, all packing a version of the brand’s new turbocharged V8 engine. Displacing 4.0-liters, this V8 can deliver up to serious power with improved fuel economy over past S versions.

In the new S6 sedan and Avant models, the engine will produce 420-hp and 406 lb-ft of torque, enabling a 0-62 mph time of 4.8 seconds. The same engine, with the same output will also be found in the new S7, which will deliver a 4.9 second 0-62 mph time thanks to a slightly heavier chassis.

All models will come standard with Audi’s quattro technology, while the S6 and S7 will get Audi’s S-Tronic dual-clutch transmission. The S8 will come equipped with an 8-speed automatic.

Audi is also touting fuel economy improvements, due to a lighter chassis as well as a new ‘cylinder on demand’ technology that will reduce the number of active cylinders to four under lighter loads.

Over the past two days there has been a constant stream of info coming from Audi about all sorts of changes in the product lineup for 2010. And here’s another one… the S8 is dead.

That’s right, the Lamborghini V-10-powered testosterone version of the A8 is destined for the history books after 2009. In the S8 the 5.2-liter engine was toned-down significantly from the Lambo, making less power but more torque for better every-day use. In total, output in the S8 is rated at 450hp and 398 ft-lbs of torque.

Another power-house Audi is also scheduled for termination, the W12-powered A8 model. Apparently Audi only sold about 100 off them last year in the United States, so it’s not likely to be missed.

Audi hasn’t commented on the reason for the changes but considering the extremely low sales volumes of these models it isn’t hard to guess that keeping production going was just wasting money and that the company is searching for ways to keep the books balanced and profits up.

The A8 is do for a (badly needed) complete overhaul in the next few years.

In related Audi news, yesterday the company announced that the 3.2-liter V6 engine would no longer be offered in the A4, TT or A3.

And on a positive note (especially for ballers-on-a-budget), Audi also said that the A5 would be offered with the 2.0 TFSI engine for 2010.

[Source: Edmunds]