A seal assembly for a turbocharger, comprising: a housing that comprises a through bore for a shaft (122, 280), wherein the housing comprisesa turbine bore segment, an inner seal ring that resists axial outward flow of lubricant for lubricating a shaft (122, 280), an outer seal ring, a shaft (122, 280) operably coupled to a turbine wheel, and comprising two ring slots for fitting the inner and outer seal rings, wherein the turbine bore segment, the inner seal ring, the outer seal ring and the shaft (122, 280) form a labyrinth seal that resists axial outward flow of lubricant for lubricating the shaft; and a longitudinal axis (x) extending generally from an inner end to an outer end of the turbine bore segment; and characterized in that, the turbine bore segment comprises an outer seat disposed proximate to the outer end of the turbine bore segment at an outer seat radius (r o) for the outer seal ring wherein the outer seat comprises an inner end, an outer end, a step at the inner end extending radially inward to a step radius (r i), and a chamfer at the outer end extending radially inward over an outward axial distance (X Cr) to a chamfer plateau radius (r Cp); and an inner seat disposed radially inward the outer seat at an inner seat radius (r i) for the inner seal ring, wherein the inner seat comprises an inner end, an outer end, a step at the inner end extending radially inward to a step radius, wherein the outer seat radius (r o) exceeds the inner seat radius (r i), wherein the inner seal ring is disposed between the step of the inner seat and the step of the outer seat and resists axial outward flow of lubricant for lubricating the shaft (122, 280). a housing that comprises a through bore for a shaft (122, 280), wherein the housing comprisesa turbine bore segment, an inner seal ring that resists axial outward flow of lubricant for lubricating a shaft (122, 280), an outer seal ring, a shaft (122, 280) operably coupled to a turbine wheel, and comprising two ring slots for fitting the inner and outer seal rings, wherein the turbine bore segment, the inner seal ring, the outer seal ring and the shaft (122, 280) form a labyrinth seal that resists axial outward flow of lubricant for lubricating the shaft; and a longitudinal axis (x) extending generally from an inner end to an outer end of the turbine bore segment; and characterized in that, the turbine bore segment comprises an outer seat disposed proximate to the outer end of the turbine bore segment at an outer seat radius (r o) for the outer seal ring wherein the outer seat comprises an inner end, an outer end, a step at the inner end extending radially inward to a step radius (r i), and a chamfer at the outer end extending radially inward over an outward axial distance (X Cr) to a chamfer plateau radius (r Cp); and an inner seat disposed radially inward the outer seat at an inner seat radius (r i) for the inner seal ring, wherein the inner seat comprises an inner end, an outer end, a step at the inner end extending radially inward to a step radius, wherein the outer seat radius (r o) exceeds the inner seat radius (r i), wherein the inner seal ring is disposed between the step of the inner seat and the step of the outer seat and resists axial outward flow of lubricant for lubricating the shaft (122, 280). an outer seat disposed proximate to the outer end of the turbine bore segment at an outer seat radius (r o) for the outer seal ring wherein the outer seat comprises an inner end, an outer end, a step at the inner end extending radially inward to a step radius (r i), and a chamfer at the outer end extending radially inward over an outward axial distance (X Cr) to a chamfer plateau radius (r Cp); and an inner seat disposed radially inward the outer seat at an inner seat radius (r i) for the inner seal ring, wherein the inner seat comprises an inner end, an outer end, a step at the inner end extending radially inward to a step radius, wherein the outer seat radius (r o) exceeds the inner seat radius (r i), wherein the inner seal ring is disposed between the step of the inner seat and the step of the outer seat and resists axial outward flow of lubricant for lubricating the shaft (122, 280).