The present work mainly focuses on study the piston ring lubrication parameters, and the influence of viscosity index improvers onthese parameters. Mathematical model has been developed using average Reynolds equation considering fully flooded inlet condition. The oil characteristics used in the modeling is enhanced by a series of polyacrylates viscosity index improvers, in order to indicate the effect of them on the oil film thickness, friction force, and hydrodynamic power losses. The simulation results help to explain the mechanism of action of viscosity index improvers in the oil during running conditions.