Generally speaking, there are 3 types of superchargers, twin-screw, roots and centrifugal. The main difference between their principles of work is how they move air to the engine’s intake manifold. The centrifugal supercharger draws air in by using an impeller. On the other hand, roots and twin-screw superchargers use various types of meshing lobes. Of course, all of these designs provide boosts, but when it comes to efficiency, they are incomparable.
The oldest design of the three is the Roots-type supercharger. These devices normally sit on top of the engine and are quite large. They have found their fame in hot rods and muscle cars. You’ve probably seen many of them as they are the ones that are sticking out of the hood of the car. Unfortunately, given that they are the oldest, they are the least efficient as well. They move air in discrete bursts instead of a continuous flow and add more weight to the vehicle.
Nevertheless, the roots blower is an engineering masterpiece and in the video below we’re checking out an animation that explains its working principles in a simple way.