This takes place just prior to the big city streets chase scene, and actually makes that whole sequence impossible. Supposedly, Jimmy Bly jumps into one of the racing "show cars" and takes off. Tanto (Stallone) then jumps in a second car and takes off after him. Here's the problem: CART cars (commonly called "Indy cars", which are the open-wheel racing cars portrayed in the movie) do not have a starter motor! In order for the engine to start, a crew member must hook a starter motor up to the engine (in the rear) to get the motor to turn over. It's basically the equivalent of the old hand-crank of cars in the early days. So, there's no way that the characters could have started the cars on their own.