1) Current-reducing auto part 2) Stability-improving auto part 
A front spoiler mounted beneath the bumper and shaped to reduce the airflow under the car. Air dams can increase the airflow to radiators, reduce aerodynamic drag, and/or reduce lift.
An air dam is a spoiler mounted at the front of a motor vehicle to reduce air flow to the underside of the vehicle and thereby improve stability.
a spoiler mounted at the front of an automobile to reduce air flow on the underside of the chassis to increase stability.
A metal strip that hangs beneath the front grill of a stock car, often just inches from the ground. The air dam helps provide aerodynamic down-force at the front of the car.