In modern automotive engines, Variable Displacement Oil Pump (VDOP) is becoming the pump of choice to reduce friction and deliver stringent fuel economy. However, this pump creates pressure ripples, at the outlet port during a complete shaft rotation, causing oscillating forces within the system and leading to the generation of tonal noises and vibrations. In order to minimize the level of noise different porting geometries and vane spacing are used. This paper presents an optimization method intended to identify the best possible spacing for the conventional 7-vanes and 9-vanes oil pumps. The method integrates a Matlab based oil pressure trace model into Mode Frontier computation platform. Bench tests are performed on several pumps with different vane spacing to measure the harmonics of the pressure ripples at the pump outlet in order to validate the results of the optimization study.