The third-generation Civic was released in September 1983 for the 1984 model year. The separate five-door hatchback and wagon models were merged into a five-door "shuttle wagon" or "wagovan" sometimes referred to colloquially as a "breadbox" because of its appearance, called the Honda Civic Shuttle. An additional two-seat coupe style—labeled CRX—was introduced, noted for its compact dimensions and light weight. The third generation Civic saw the introduction of the long running four-cylinder D series engine including a new 1.5 L (91.5 cu in) CVCC engine producing 76 HP. 1984 also saw the release of a high-performance Si model for the Japanese market, featuring upgraded suspension and the 1.6 L (97.6 cu in) double overhead camshaft(DOHC) ZC engine which was rated at 130 PS (128 HP). Si models were offered in the U.S. as a 3-door Civic Si hatchback and the CRX Si variant with a 91 horsepower (68 kW) single overhead camshaft (SOHC) 12-valve engine with programmed fuel injection. A 4WD configuration with different transmission mounts was introduced for the first time in 1984, and later upgraded in 1987.