Green’s Dictionary of Slang

1. intensified, accelerated, usu. of a car that has been modified by its owner to exceed the basic factory-created performance.

1949		A. Hynd We Are the Public Enemies 7: Dillinger used a Ford with a souped-up motor when dusting from a job.
1951		Kerouac On the Road (The Orig. Scroll) (2007) 182: A burly blond kid in a souped-up rod.
1959		H. Ellison ‘No Game for Children’ in Gentleman Junkie (1961) 79: Didn’t he have his own souped short?
1966		H.S. Thompson Hell’s Angels (1967) 97: There are also stories about outlaws on souped-up hogs being humiliated by lightweight Ducatis.
1969		N. Cohn Awopbop. (1970) 130: The music they played then was souped-up rock.
1971		N. Armfelt Catching Up 200: Some suped-up old Dodge.
1979		E. Torres After Hours 129: Couple of kids in a souped-up car.
1989		M. Amis London Fields 247: Thelonius opened a trembling palm in presentation of his new car – a souped-up, low-slung maroon Mini.
1999		Indep. on Sun. Real Life 6 June 1: Tearing about town on a souped-up scooter.
2001		K. Sampson Outlaws (ms.) 1: Little pricks in souped-up E-Reg Polos and that, divvy hatchbacks and that.
2008		D.R. Pollock ‘I Start Overin Knockemstiff 165: A souped-up 1959 Chevrolet with big fins.
2013		D. Whish-Wilson Zero at the Bone [ebook] His days of car chases were over. With all the souped-up models on the streets these days, he wouldn’t stand a chance.
2017		V. McDermid Insidious Intent (2018) 123: Dominic was driving a souped-up Vauxhall.

2. in fig. use, of a person.

1984		S. King Thinner (1986) 50: He’s got a souped-up metabolism.
1992		D. Burke Street Talk 2 50: Souped – conceited. She may be too cold but she’s souped.
1995		(con. 1985–90) P. Bourjois In Search of Respect 291: I would try to get ahold of some niggas on my block who are really souped up. And if they look like they got something, then I’ll let them.