1
general::
Make something more powerful; especially, add speed to an engine. For example, He was riding around in that car he'd souped up, or They had to soup up the sound system for the outdoor concert. [Slang; c. 1930]
American Heritage Idioms
2
general::
Phrase(s): soup something up
to increase the power of something. • He souped his car up so it will do nearly 120 miles per hour. • If only I could soup up this computer to run just a little faster.
McGrawhill's American Idioms And Phrasal Verbs