http://www.youtube.com/watch?v=9zyf2W1aOWs
Not too long ago, Porsche unveiled the car that will mark its return to the top flight of endurance racing - the 919 Hybrid. Surprisingly, the race car did not bear the iconic flat-six or a V8 engine - but rather a relatively smallish 2.0-litre V4. Recently, the 919 was caught testing - and how it sounded surprises all that were present. We bet you will too after watching the video above.