Audi S4 and S5 to go four-cylinder!

If you were surprised when Audi launched its 2010 S4 with a six-cylinder motor rather than another V8, you better be sitting down to read this. According to engineering director Michael Dick, the 2014 Audi S4 will have a turbocharged four-cylinder engine under its hood -- and so will the next S5.

How is it possible for a four-banger to deliver the level of performance worthy of an "S" badge? The answer has as much to do with the rest of the car as it does with the motor. Mr. Dick told Car and Driver the new S5, for example, will be 880 pounds lighter than the existing model. He said Audi will increase its use of structural aluminum and magnesium to achieve this goal. The 2012 A6 will also make use of lighter materials, he said.

Dick went on to say the S5 prototypes currently being tested weigh around 3,000 lbs, with all the same safety features as the current car. Performance is said to be improved as well -- the cars are reportedly able to lap Germany's Nurburgring race track eight seconds faster than the current S5.

The 2014 S4 and S5 prototypes currently being tested look identical to today's models, but the production cars will get a freshened look with cues from the forthcoming A7, which is based on the Audi Sportback Concept.

In the interim, the 2011 S5 is expected to lose its V8 in favor of the same V6 that's in the new S4.

With Mercedes eliminating most of its V12 offerings and BMW increasingly turning to smaller engines with turbochargers, it's clear German automakers are moving away from high-displacement high-horsepower motors. Does this mean the "horsepower wars" are officially over? We certainly thinks so. Enter the "efficiency wars."