OEM spoilers

OEM spoilers are factory or factory style spoilers, to match the original OEM spoiler that would have being a factory option.

Sports cars are most commonly seen with front and rear OEM spoilers . Even though these vehicles typically have a more rigid chassis and a stiffer suspension to aid in high speed maneuverability, a spoiler can still be beneficial. This is because many vehicles have a fairly steep downward angle going from the rear edge of the roof down to the trunk or tail of the car. At high speeds, air flowing across the roof tumbles over this edge, causing air flow separation. The flow of air becomes turbulent and a low-pressure zone is created, increasing drag and instability . Adding a rear spoiler makes the air "see" a longer, gentler slope from the roof to the spoiler, which helps to delay flow separation. This decreases drag, increases fuel economy, and helps keep the rear window clean.

One of the best remembered factory / OEM spoilers is the wing on the Road Runing Superbird and the Charger Daytona in 1970.

The main design goal of a spoiler in passenger vehicles is to reduce drag and increase fuel efficiency. While many often imitate wings and airfoils,  these serve mostly decorative purposes. Passenger vehicles can be equipped with front and rear spoilers. Front spoilers, found beneath the bumper, are mainly used to direct air flow away from the tires to the underbody where the drag coefficient is less. Rear spoilers, which modify the transition in shape between the roof and the rear and the trunk and the rear, act to minimize the turbulence at the rear of the vehicle.

Also new vehicles today not only have rear spoilers, the also have front spoilers. The front spoilers, also known as an air dam helps to move the air over the front of the vehicle and not under the vehicle which create lift.