Turbocharger maps are used in design, evaluation and optimization of engine system operation to represent the turbo operation in different scenarios. To construct such a map, the turbo is tested in a gas flow test bench, called gas stand. Turbo testing is a time and resource consuming experimental process. The turbo is tested in a selected number of test points for different turbo rotational speeds, where the temperatures in the turbo have to be stationary when the measurements that constitute the map are acquired. In this paper, optimal control is used to find the most time efficient pattern of test conditions, and the optimal control strategy to traverse between them. A heat transfer model, describing the heat transfer between the compressor, bearing house, and turbine, is presented and validated against measured data. A direct collocation method is used to find time optimal control trajectories between the specified test points in the map. The method objective is to find the least time consuming control strategy which brings the turbo from one test point to the next, while ensuring thermal equilibrium at the final time. The results suggest that this method reduces turbocharger testing time with a factor higher than 60. The improvements can be further increased, with over 70 times, if a traveling salesman problem is solved to find the optimal route through the turbo map. The described method would be able to map a 43 points turbo map in 22 minutes, including a 5 minute warm-up phase. (C) 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.