Rb b l koots, or Eaton-style, superchargers are probably the most recognized |blowers in the world. As a Mopar lover, you might not like the fact that modern Roots blowers evolved from the GMC 6-71 blower developed in the 1930s, but you have to love the fact that blown Hemis using this type of supercharger have continuously dominated the top classes in drag racing for many years. There are no GM parts in modern Roots blowers, however, because manufacturers such as Littlefield, Eaton, MagnaCharger, BDS, and Holley/ Weiand build completely new Roots blowers and blower kits for almost any application.
The compressor of the Roots blower is a positive displacement pump, containing two rotors spinning inside the blower housing to pump air. Early Roots blowers had either two or three-lobe rotors that were straight cut, but modern designs utilize helical rotors with Teflon seals to form a tight clearance between the rotors and the housing. Either way, the air or air and fuel enter the top of the blower, and the mixture is then pumped outward and down the inside of the rotor case, exiting at the bottom. This style of blower typically sits right on top of the engine which creates higher inlet temperatures than centrifugal superchargers. Roots-style blowers are also more difficult to intercool, though there are air/water intercoolers that sit between the blower and the intake.
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