A boost control device for a turbocharger, assembled at room temperature, may not be geometrically optimal at turbocharger operating temperature. The geometric deviation in the boost control device introduced by the heating of the turbocharger to operating temperature, or during welding of the boost control device, is corrected by producing a first turbocharger at room temperature, determining the geometry of the deviation at operating temperature, producing a distance element that will introduce an equal and opposite deviation, introducing the equal and opposite deviation via the distance element in second and subsequent turbochargers, whereby thermal deviation and corrective deviation offset so that the turbocharger is geometrically accurate at operating temperature.