Booster for a dragster

TURBO

A high-speed engine might rely on this forced-air component to gain extra power.

A "booster for a dragster" hints at something that gives extra speed or power to a racing car. "Turbo" fits perfectly because it’s short for turbocharger, a device that forces more air into an engine to increase its performance. The clue plays on the idea of a "boost" in both literal (mechanical) and slang (speed-enhancing) senses. It’s a straightforward definition with no hidden wordplay—just a direct nod to automotive tech.