REAR CLIP

The section of a race car that begins at the base of the rear windshield and extends to the rear bumper. Contains the cars fuel cell and rear suspension components.

RESTRICTOR PLATE

An aluminum plate that is placed between the base of the carburetor and the engines intake manifold with four holes drilled in it. The plate is designed to reduce the flow of air and fuel through the carburetor decreasing horsepower and speed. NASCAR keeps control over all restrictor plates and issues them during tech inspection. They are numbered and have a special seal and can't be removed without the consent of NASCAR. "Plates" are used only at Talladega and Daytona. Plate racing requires a different touch on the throttle. If a driver jumps off and on the throttle he runs the risk of "leaning out the motor (starving for fuel) and burning a piston.

ROOF FLAPS

These flaps are sections at the rear of a race car's roof that are designed to flip up, if the car gets turned backwards. They actually work in disrupting the airflow over the car and keeping it on the ground. Sort of like flaps on an airplane.

ROUND

A wrench is inserted in a jack bolt in the back window of the car to raise or lower the track bar. This changes the spring rate on the rear of the car and changes the wedge of the chassis. This in turn can loosen or tighten the handling of a race car. A round is one full turn on the jack bolt. A driver may say, "Give me two rounds or a half a round..."