Turbine Housing TypeSelectv-band turbine housing, single scroll, 1.04 a/rv-band turbine housing, single scroll, 0.94 a/rv-band turbine housing, single scroll. 0.85 a/rt4, 0.91 a/r, twin scroll turbine housing (supports 76mm turbine wheel)t4, 0.91 a/r, twin scroll turbine housing (supports 80mm turbine wheel)t4, 1.00 a/r, twin scroll turbine housing (supports 76mm turbine wheel)t4, 0.88 a/r, single scroll turbine housing (supports 80mm turbine wheel)t4, 0.88 a/r, single scroll turbine housing (supports 76mm turbine wheel)