The phrase "souped-up" has origins both in cooking and food technology advancements. Specifically, standard models of a car are referred to as "cooking". When someone adds stripes, large exhaust, then it's taken to simmering. Once the engine is uprated, it's "hot" - although this terminology also applies to inexplicable thefts of 1988 Metros from sink-hole estates by 15 year old morons.
To further expand upon this, the 1920s hot-rod community fuelled by prohibition and the need to run moonshine great distances fast in rural USA adopted cooking terms for their modified vehicles, but had to distinquish between these terms and the terms they used for their moonshine production - where boiling, simmering, hot, cold etc. would also apply (also fermenting, but that's more likely to apply to the stale vomit and spilled milk in the back of any Scenic/Picasso/Zafira middle-class virility badge these days).
Pop culture was taking hold - it wasn't long until Andy Warhol was to be born - and his influence was already coming through. The 'shiners adopted soup terminology with varying degrees of success - supercharging and skimmed heads were no longer "compression", but "condensed", as you got more bang in a smaller space (remember that early American cars had engines approaching 20 litres per cylinder, so like the process of making the power of Univac pocket sized, engines also had to be miniaturised - early days! I remember when the first Youngsmobile (they renamed them Oldsmobiles later) was released you could stand a full grown man in one cylinder bore!).
"Cream of" was an early form of water injection. "Noodle" was used to refer to the practise of adding additional leads from your magneto to the ignitors. "Won Ton" was the target weight and load capacity. "Cullen Skink" was the practise of getting in touch with the well known tuner/'shiner, Skink "Arthur" Rogers.
So, clearly the term souped-up doesn't involve actual soup, but does have origins in food production.