imagine a sports car, maybe a miat
>miat has a small pack of batteries under floor to help 50/50 weight distribution
>miat has extra electric motor like honda IMA systems
>miat uses the electric motor for braking
>miat when braking is loading a "boost" gauge
>after around 5 minutes of driving boost is ready
>you press button and your miat has extra 100hp for 30 seconds
>after that the electric system has to recharge and motor has to cool down

just think about it like IRL boost system from vidja games

just imagine motorsports with such a cool system