Turbochargers are used with small displacement passenger car engines to improve fuel combustion and increase power output. Since turbochargers generate higher temperatures and pressures, they are a potential source of a number of operating problems. Lubricant-related concerns are primarily due to the increased propensity for oil degradation and deposit formation in the turbocharger. Early experience with turbocharged passenger car engines confirmed that lubrication problems could be encountered.This paper describes the application of a bench engine dynamometer test method to evaluate lubricant performance and discusses the measurement of turbocharger deposits and their relevance. Field tests and the bench engine dynamometer tests are also compared.