During the development of ECU software, physical/environment model plays major role in simulation and prediction of engine behavior. Hence it is necessary to bring simulation results from the model as close as possible to the real environment. Once the model is mature enough it is used as a bench mark for designing a control strategy. The present paper deals with the identification of most influencing parameters (MIP) for given operating condition to have a desired behavior of the airpath model. The airpath model is validated with reference model. Multi input multi output (MIMO) model is cross verified with recordings and the MIMO model is benchmarked. The author describes in detail the application of statistical study needed to arrive at a decision which is supported by the nature of outcome by having probabilistic studies of MIP. A small signal analysis via perturbation is done on the model to check the stability and response of the system in steady state. The model with and without observer is simulated to check the performance of the model. © 2017 The Authors. Published by Elsevier Ltd.