The first iteration of the Acura NSX was introduced for model year 1991, although it was available in non-US markets as the Honda NSX in 1990. It was powered by an all-aluminium 3.0 L V6 engine, which featured Honda's VTEC (Variable Valve Timing and Lift Electronic Control) system developed in the 1980s, in automatic or a 5-speed manual transmission. Cars with the 3.0 liter engine are known as NA1 models. Initially launched as a coupe, the NSX received its first major evolution for model year 1995 in the form of a Targa-like roof top, cars that are known as the NA1 NSX-T.