RumBum wins Road America, but Porsche misses a class sweep | IMSA news | Motorsport.com Posted on August 9, 2015 by mtnnews Posted in Motorsports Pumpelley in RS1 Cayman runs out of gas two turns from an ST class victory. Source: RumBum wins Road America, but Porsche misses a class sweep | IMSA news | Motorsport.com