How it Works: Audi 4-Liter Turbo V-8

Thirty years. That's how far Audi's previous V-8 engine dates back, albeit with numerous updates along the way. But in light of ever-tightening emissions and fuel-economy regulations, Audi decided an all-new design was needed. Thus was born the 4.0-liter twin-turbo V-8, sporting an all-aluminum …