The term 'RACE THE ENGINE' is a phrase used to describe the process of revving an engine to its maximum speed. The crossword solutions for this term are REV, which stands for 'REVOLUTION'. Revving an engine is the process of increasing the speed of the engine by turning the crankshaft faster, usually done by pressing the accelerator pedal. This process is often used to test the performance of an engine or to warm it up before driving.