NASCAR debuts lower downforce aero package at Atlanta

The aerodynamic package is similar to the ones used at Kentucky and Darlington last year. Lowering the downforce on a car makes it harder to drive, which puts more emphasis on driver skill and increases the potential for more passing.

Changes to the Sprint Cup car for this season's aero package include reductions to:

Spoiler - 2015: 6" tall, 2016: 3.5" tall

Air coming over the top of the car hits the spoiler, which pushes the back of the car down. A shorter spoiler creates less downforce than a taller spoiler.

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Splitter - 2015: 2" overhang, 2016: .25" overhang

The splitter "splits" air and forces it to accelerate under the car, creating a high-pressure zone above the splitter and a low-pressure zone underneath that sucks the car down. Shortening the splitter reduces downforce.

Radiator Pan - 2015: 38" wide, 2016: 33" wide

The radiator pan is a flat panel that extends behind the splitter and under the car, deflecting air to create more downforce. A narrower panel is less effective in deflecting air, which slows airflow and creates less downforce.

Practice starts Friday at 11:00am in Atlanta, and qualifying will begin at 5:45pm later today.

Adapted from nascar.com press release