 To calculate this efficiency, it is necessary to do the calculations of the 2 stages, first calculate the conditions of pressure and temperature at the exit of the first stage and starting from these to do the calculations for the second stage.Following the previous example, for a first stage of the turbocharger (efficiency of 70%, pressure ratio of 1.7) the temperature would reach the after the first stage, to then enter the roots (efficiency of 60%) and leave at a temperature of .This is a total efficiency of 62%.