Founded by former race crew chief and car owner Art Whipple in 1987, this Fresno, California, company manufactures twin-screw superchargers for automotive and marine racers and anyone else looking to improve their engine’s performance. As one of a few different types of “power adders,” as they are commonly referred to (turbochargers and nitrous oxide are others), superchargers introduce additional air into an engine beyond what the engine can pull on its own. The more air that can be delivered into the engine, the more fuel that can be proportionally added. That means the engine’s displacement becomes “bigger” than it physically is, producing more horsepower.
The accurate, non-contact meshing of two helical rotors inside a casing is the key for proper function of twin-screw superchargers. With the Whipple design, the male rotor has three helical lobes and the female has four, explains Supercharger Designer Garrett Bright. These rotate counter to each other and extremely closely. As the lobes of each move past air inlet ports, the air becomes trapped between the rotors and casing. Rotor rotation progressively reduces the space the air occupies, compressing it. Compression continues until the inner-lobe space becomes exposed to an outlet port, through which the air is discharged higher than atmospheric pressure into the intake manifold that sits atop the engine.
Supercharger efficiency depends on how effective sealing is between the mating rotors and the casing. Until recently, Whipple had solely used rotors manufactured and supplied by a European company. It still uses those supplied rotors for some of its supercharger models. However, Whipple has since started to design and machine its own rotors in house, and the machining process it has developed produces more cylindrical and accurate rotors than those its supplier provides. In fact, more precise machining means new supercharger designs are 5% more efficient than those using the supplied rotors.