Le Mans: 2014 — it's all about efficiency

http://auto-racing.speedtv.com/article/le-mans-2014-lmp1-regulations-announced/

/ Automobile Club de l'Ouest FIA technical regulations LMP1 cost reduction and safety category will closed-top prototypes closed top 30 percent reduction in fuel consumption World Endurance Championship American Le Mans Series energy recovery systems 2 to 8 MJ of power /