The kinematic viscosity has to be given for two temperatures: ν40 at 40°C and ν100 at 100°C. The actual viscosity at the given temperature will then be interpolated using these values.
If a single kinematic viscosity at operating temperature is given, it can just be entered in both inputs and therefore will be used in the calculation.
A high viscosity results in a larger lubricant film, but efficiency will be reduced if it is too large.
