The integral, non-linear and time-dependent Kaye-Bernstein-Kearsley-Zapas model (K-BKZ) offers significant advantages (e.g. better pressure forecast or visualisation of vortexes) for fluid-flow simulations of polymers, since it allows the mapping of viscoelastic material behaviour. To simulate with the K-BKZ model, it is crucial to measure the viscoelastic material parameters in a wide frequency and temperature range. These include (1) the elongational viscosity, (2) the shear viscosity, and (3) the storage and loss moduli. Therefore, the transient elongational viscosity was determined, using a Sentmanat Extensional Rheometer tool in a Modular Compact Rheometer MCR501 (Anton Paar GmbH), for strain rates below 10 s-1. Moreover, the steady-state elongational viscosity was estimated from the measured inlet pressure loss in a High-Pressure Capillary Rheometer (HPCR, Goettfert Werkstoff-Pruefmaschinen GmbH) using Binding’s, Cogswell’s, or Obendrauf’s approach. While a Rubber Process Analyser (RPA, MonTech Werkstoffpruefmaschinen GmbH) was used to detect the complex viscosity and the storage- and loss moduli for angular frequencies below 300 rad/s, HPCR results gave the steady-state shear viscosity. The comparison of the complex viscosity to the steady-state shear viscosity proves that the Cox-Merz rule is invalid for a highly filled HNBR rubber compound. In contrast, the dynamic viscosity and the steady-state shear viscosity correlated well. Finally, one approach to fit experimental data with the K-BKZ model, using a damping function proposed by Wagner, will be shown exemplarily and discussed in detail.