SummaryThe tightening of emission requirements drives the automotive industry to constantly improve efficiency and fuel economy, and it's a megatrend affecting automotive design and operation today and into the future. Among the various technical options for improved fuel efficiency, lubricants are very cost effective. Viscosity plays an important role in efficiency, and VI Improver selection is key for developing lubricants with optimum efficiency. In this study, advanced comb polymer Viscosity Index Improvers were compared with standard VI Improvers in formulations using same performance additive package and the same base oil. In a high-precision, dynamic bench test real vehicle conditions were simulated in NEDC and WLTP cycles. The lubricant formulations based on comb polymer VI Improver achieved up to a 1.5 % improvement in fuel economy in the NEDC test cycle and up to a 1.6% improvement in fuel economy in the WLTP test cycle.