The drive to reduce costs and increase efficiency in the automotive industry is often the driving force for development of new technologies and methods of engineering. Polypropylene (PP) is widely used as a low cost alternative to “engineering” thermoplastics. This paper outlines the characterisation methods used to develop material models for talc-filled impact-modified PP, which are then used to increase the efficiency of the development process, by using engineering analyses to reduce the prototyping costs and potentially the development time for an application.Instrument panels (IPs), door panels and trim parts are usually subjected to heat requirements and must maintain dimensional tolerance levels for each application. This necessitates extensive prototype testing and often several design iterations in order to reach the requirements. This paper deals with the characterisation of PP creep behaviour and development of a model for use in Finite-Element (FE) - based codes. Engineering analysis is then used to predict the behaviour of an application during heat testing.Characterisation of talc-filled impact-modified PP for impact situations is also considered. High strain-rate data are used to develop a model of the material, which is correlated with impact testing.