Innovations for the U12 included the introduction of Nissan's mechanical four-wheel-drive system, called ATTESA and the ever-popular SR20DET engine which was introduced in the series 2 (HNU12) bluebirds (1989–1991). With the Maxima having been spun off into its own range, U12 Bluebirds were all four-cylinder models, with either a 1.6-, 1.8-, or 2.0-liter petrol engine and also the option of the LD20 2.0-liter diesel. The sports and luxury versions came with a factory viscous LSD. Nissan made a turbocharged Bluebird from 1987 to 1990 named the RNU12, using the 1809 cc DOHC CA18DET that was sold in Japan and New Zealand. It, too used the ATTESA system.