Evaporation coefficients of SiC have been introduced in the simulation of SIC growth by the Physical Vapor Transport (PVT) method. The total pressure of the reactive species in the gas phase over solid SiC changes compared to previous calculations, where equilibrium conditions were considered at the source powder surface. With these new boundary conditions we simulated the growth of SiC single crystals for two different total pressures (4 mbar and 13 mbar). The shape of the growing crystal is flat at higher pressure and convex at low pressure. This behavior as well as a growth rate of 0.6 to 2.0 mm/h are comparable to the experimental observations, indicating the potential of this approach.