The present study describes a computer-integrated design modification strategy for a torque converter using virtual modeling and flow analysis. As a preliminary analysis tool, the present study adopted one-dimensional performance analysis with a forced vortex method and a corrected blade angle with flow angle based on three-dimensional flow analysis. From the results of the performance analysis, first-stage optimized blade angles were determined with satisfying design requirements. A CAD program was developed for the virtual modeling of blade geometry with newly chosen blade angles and design path radii. As an accurate inspection tool, a computational fluid dynamics program adopting the mixing plane model was developed with flow and performance analyses for a virtually modeled torque converter, which involves a full three-dimensional flow calculation of a torque converter. This computer-integrated design strategy can significantly reduce the time and cost for the design of an optimized torque converter.