In this research, some robust and versatile turbulence models were examined in simulation of engine non-equilibrium and anisotropic turbulent flow. Comparisons were made using RNG k-e, Rietz-modified RNG k-e and compressible RSM (LRR version) models in resolving the time delay between mean flow changes and its proportionate turbulence dissipation rate. The turbulence integral length scale which is a proper criterion for examination of the turbulence models performance in predicting the dissipation rate was applied to evaluate the models. Results showed that RNG k-e model cannot predict a realistic behavior for turbulence integral length scale in an engine. Integral length scale calculated by compressible RSM model, however, is in good agreement with the one predicted by Rietz-modified RNG model. It is commonly accepted that, RSM turbulence model provides better prediction of engine flow characteristics such as velocity profile and recirculation zones in comparison with eddy viscosity models. But, to the best of the author’s knowledge, there has been no attempt to investigate the performance of a RSM model, namely compressible LRR, in predicting turbulence length scale for engine flow applications. Therefore, in the present paper the capability of RSM model in calculating of turbulence characteristics such as turbulence length scale was studied and confirmed in complex engine flow conditions.