With increasingly strict legislation and further the introduction of a new testing procedure WLTP, the highly detailed knowledge of engine friction becomes essential to obtain further fuel economy reductions. The new Worldwide Harmonized Light-Duty Vehicles Test Cycle WLTC driving cycle will not only test a larger range of engine operation conditions, but also brings fundamental changes to the way the powertrain is evaluated. In the following, a novel engine friction testing method is used together with a highly accurate simulation to analyze engine friction exemplary for the Renault Energy dCi 130 Diesel engine in great detail and discuss the results in view of the upcoming new testing procedure. The differences between the NEDC and the WLTC driving cycleFigure 1: vehicle velocities tested in the NEDC and WLTP testing procedures (colors mark the individual phases of the tests).