A variable nozzle system can comprise a gas inlet ring, an opposing gas outlet ring, an actuation ring, guides, and vanes circumferentially spaced about and disposed between the gas inlet ring and the gas outlet ring. The gas inlet ring, the gas outlet ring, and the vanes can form nozzles, the nozzles being variable by rotation of the vanes about a pivot axis. The plurality of guides can extend from the gas inlet ring, the gas outlet ring, or the actuation ring, and the vanes can be connected to the actuation ring, so that each vane can be rotated by rotation of the actuation ring and by sliding against a respective guide from the plurality of guides. The actuation ring can have a gear rack and can be rotated by rotatable engagement of the gear rack with a pinion attached to the end of a rotatable gear shaft.