Mazda debuted their new diesel Mazda6 race cars at the Rolex 24 hour endurance race in Daytona in January. The entire lineup of engines in the new 2013 Mazda6 have benefited from Mazda’s SkyActiv engine technology initiative. It’s interesting to note that while the gasoline engines have increased compression ratios to improve efficiency, the diesel engines worked the other way. Diesel compression ratios are generally in the neighborhood of 20:1, but Mazda found that lowering it about 14:1 meant that all of the engine parts could be significantly lighter which allowed for higher rpm’s and lower bearing friction.
Source: Road and Track on YouTube