Atreyal Ransom has a firm handshake. He stands just 5 foot 9, but his presence is commanding. Although he had spent the afternoon instructing children at a community center in Coney Island, Brooklyn, his collared shirt and slacks remained unwrinkled. He was serious.

But when the conversation turned to cars, he talked fast and his demeanor changed.

“My dream car, that’s a Subaru BRZ,” Mr. Ransom, 19, said recently, his eyes brightening. “You can do a lot with that car because you can change it to be just the way you want it. Me, I like loud cars.

“The first thing I’d do with that car is get it turbo-charged,” he continued. “It’s hard to explain, but turbo-charging your car is like music, like finding your perfect song.”

In a mechanics class in high school, he was the only student to rebuild a broken car engine, said to be irreparable. Going beyond the requirements of the project, he souped-up the engine, and not just for the amplified sound. “I have a need for speed,” Mr. Ransom said with a laugh.