Electric superchargers produced by Valeo, Mazda and Phantom Supercharger are considered to be some of the most effective of the devices in use, as of 2015. However, most electric superchargers sold for after-market installation are not effective at boosting either engine output or fuel efficiency.
An electric supercharger uses an electric motor to compress air for forced induction into a car engine, rather than the belt-driven motor used by most mechanical superchargers. The primary advantage of electric superchargers is that they do not leech mechanical energy from the engine, while retaining the quick response time. They also do not have the turbo lag that is characteristic of a supercharger, as compared to a turbocharger.