In this paper the methods to increase the rotor speed of the jet-operated centrifugal oil filter are presented: 1. The reasonalbe jetting direction is investigated with consideration of energy utilization. It is better to make the jet declining downwards. 2. Formulas to calculated optimum arm of force are proposed. 3. Diminishing diameter of the upper bearing is suggested to decrease the resisting moment. 4. Unbalance of the funning rotor should be kept blow a suggested value.