Implementations of the present disclosure are directed to turbine assemblies for turbocharger systems. In some implementations, turbine housings include a body that defines an inlet for fluid communication with a fluid source, and a wall, the wall dividing the inlet into an inner inlet and an outer inlet, and a fluid guide assembly disposed within the housing, the fluid guide assembly including a plurality of vanes that demarcate an inner volute and an outer volute within the housing, the inner volute being in fluid communication with the inner inlet and the outer volute being in fluid communication with the outer inlet, each vane of the plurality of vanes being fixed at a respective angle relative to a radial direction, the plurality of vanes guiding fluid flow from the outer volute to the inner volute.