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. These initial cars was powered by an all-aluminium 3.0 L V6 engine, cars that 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 removable roof top, cars that have become known as the NA1 NSX-T. Sold until 1998, the NA1's were phased out by the more powerful NA2 models starting in 1997.