Abstract: A variable-nozzle turbocharger includes a variable-vane mechanism that has an annular nozzle ring supporting an array of rotatable vanes connected to vane arms whose distal ends engage recesses in the radially inner periphery of a rotatable unison ring. Rotation of the unison ring causes the vane arms to pivot about their respective pivot axes at the proximal ends of the arms. The vanes are locked in their fully open position by a locking arrangement that includes locking tongues that extend radially inwardly from the inner periphery of the unison ring and contact the vane arms intermediate their distal and proximal ends.