A turbocharger has a meridionally divided scroll comprising a first scroll and a second. A dividing wall that separates the two scrolls from each other has an evolutive thickness distribution as a function of angular location about a rotational axis of the turbine. In an embodiment, the dividing wall has a V-shape, and the included angle of the V-shaped dividing wall varies from a maximum value at a 0° angular location to a minimum value at a 360° angular location. As such, the thickness of the dividing wall correspondingly varies from a maximum value at the 0° angular location to a minimum value at the 360° angular location.