soup up

soup up (third-person singular simple present soups up, present participle souping up, simple past and past participle souped up)

1. (informal, transitive) To modify the engine of (a motor vehicle) to give a higher performance than the specifications.
   • 2009 October 19, Paul Rees, “Flying backs become walking wounded as blitz defence has its impact”, in The Guardian:

     Imagine souping up a Mini with a Cosworth engine: the car would fly.

• tune up