In direct-injection diesel engines the combustion process, is strongly influenced by the turbulence of the spray-induced flow. This flow is transient in nature and, therefore, the equilibrium-based k-epsilon-type turbulence models yield inaccurate Predictions of the turbulence mixing time scales. This requires adjustments of the turbulence characteristic combustion time by means of the coefficient C-M, in order to match experimental cylinder Pressures of different engines. These adjustments are explained in terms of nonequilibrium turbulence behavior of the spray-induced flow. A relation between the spatially averaged equilibrium and nonequilibrium turbulence time scales is derived which leads to a scaling law between the different engines. In particular, the value of C-M for one engine can be obtained from the optimum C-M of another engine, provided the turbulence determining integral length scales are known. This scaling behavior has been demonstrated for four substantially different engines by comparing the tuned values of C-M with the computed scaling factors, and favorable agreement has been obtained.