“CAE and testing go hand in hand”: this is one of the basic rules for a cost- and time-efficient mechanical development process of state-of-the-art engines for mass production. In this article by FEV Motorentechnik GmbH, it will be exemplarily shown how these technologies can be combined with experimental investigations so as to find solutions for non-standard development problems — quite often, the concerted cooperation of calculation and measurement is the key to success.