In 1994 Indycar powerhouse Penske exploited a loophole in the engine regulations to dominate the Indianapolis 500. How did they do it? Our technical expert Jake Boxall-Legge explains the story of how the engine that would be dubbed the Mercedes-Benz 500I was created - a project so secret that many of Penske's employees had no idea it was being developed until it was almost time to take it to the Speedway