This situation is impossible. First of all, the motor of four-wheel drive racing car is DC motor, because the direction of current determines the direction of magnetic field. After changing the positive and negative poles, the change of current direction will inevitably change the direction of magnetic field, and the motor will definitely reverse. This situation only applies to DC motors, where voltage is applied across the motor. If there is a circuit between the motor and the battery, it will be different. For example, connecting a bridge rectifier between the motor and the battery will definitely not change the direction of rotation.