Powershifting, or bangshifting, as it is sometimes called, is a technique drag racers often used in the past to get down the track more quickly. Without any of the modern driver aids, it was entirely up to the driver to squeeze every last tenth of a second out of the car. This is where the practice of powershifting came in, which basically entailed keeping the throttle wide open as you quickly shifted the car into the next gear, in order to maintain as much momentum as possible. It takes some skill to do it well, and if done wrong, could have catastrophic results. If you ever watch Roadkill Garage, you will know that Steve Dulcich often likes to exhibit his bangshifting abilities.