IMSA takes North American sports cars into hybrid era

The Meyer Shank Racing Acura ARX-06 passes the High Class Racing ORECA LMP2 07 in a turn during a practice session for the Rolex 24 hour auto race at Daytona International Speedway, Thursday, in Daytona Beach, Fla. (AP Photo/John Raoux)

DAYTONA BEACH, Fla. — The Cadillac growls, while the Porsche and BMW scream. The Acura sounds like an Indy car, and for fun, turn your back to the track and listen carefully as the cars roar around Daytona International Speedway in a new era of IMSA sports car racing.