How is MEHF different from a standard HV or high VI fluid?
The ASTM and ISO definitions of the HV product grade, and the JCMAS definition of the high VI “W” grade, require that the fluid have a viscosity index of over 130. These fluids are primarily designed to provide good low temperature start-up performance, which they do quite well. The MEHF performance level has been developed to describe fluids that provide good low temperature fluidity AND excellent high temperature viscosity performance, such that pump efficiency is maximized at BOTH low and high temperature. A standard HV or high VI product may offer some pump efficiency gains at high temperature, however, the MEHF definition requires the combination of high VI (>150) and good shear stability which insures optimized pump efficiency for increased power and productivity over the full range of operating conditions.
