Turbocharging has nowadays become a common solution to complete downsizing in the quest for reaching the new polluting emission constraints. Besides to reduce the developing costs and meet the ever tightening regulations, car manufacturer relies more and more on computer simulations. Thus developing an accurate and predictable turbocharger model, functioning on a wide range of engine life cases, is now a requirement. In the current models, compressors and turbines are represented by look-up tables, experimentally measured on a turbocharger test bench, at steady point and high inlet turbine temperature. This method results in limited maps : the compressor choke line depends on the test bench, and a typical turbine iso-speed is limited to a 0.5 ratio range. Put up on an engine, the turbocharger encounters a wider scale of functioning points. using only the present compressor and turbine maps in an engine simulation model no enough. For this paper a specific experimental campaign is performed with different automotive turbochargers on a test bench in order to expand the measured iso-speed lines. On the compressor side, new measurements methodologies are described - into the choke area, up until a ratio of 0.8, - beyond the surge line, into the negative mass flow rate. On the turbine side, several complementary approaches - using different temperatures, compressor overload…- are implemented to expand the turbine iso-speed lines from 1 to 5 ratio. Based on these results a mathematical model is presented, enabling to expand the current manufacturer compressor and turbine maps to these wider scales.