If you know your physics, you know the faster a flywheel spins, the more energy it stores. As that energy is released as torque, its speed reduces. Applying that principle, one engineering student slapped one on a bicycle as an energy booster.

Before Porsche builds a handful of its 918 Spyder plug-in hybrids, it has to finish the production bodywork, which it teased today as part of an expansion of its research labs, which cost the equivalent of 250 Porsche 918 Spyders.

The flywheel-enhanced Porsche 911 GT3 R Hybrid outran the GT field in a Le Mans-class race in China on Sunday, besting the regular 911s, Ferraris and BMWs by more than two laps with one less pit stop. (Photo: Porsche)

Petit Le Mans, the 10-hour endurance race at Road Atlanta, is this weekend. Peugeots, a Porsche hybrid, Panoz — If you've got a TV and you love cars, what the hell else would you watch on Saturday?