What is the difference between the Lysholm twin-screw compressor and a common roots-type supercharger such as an Eaton?
A. The Lysholm twin-screw supercharger is actually a compressor, which means it compresses air internally as well as compressing it in the manifold. Because the screw compressor compress?s the air inside the case, air enters into the pressurized environment with very little leakage or energy loss. A roots-type supercharger sweeps atmospheric air into the manifold and is compressed in the manifold only. With manifold pressure, air leaks back through the rotors causing air to be heated. Roots-type uses Teflon to try and seal the rotors to cure this, but touching tolerances cause more frictional heat and greater parasitic losses. This problem is multiplied when boost levels rise or sustained in-boost periods. Automotive and Marine roots-type superchargers have more tolerances between the rotors and case so they live longer, but this causes more leakage back through the rotors. A screw compressor has very tight tolerances between the rotors. The rotors never touch, eliminating big parasiti
