MZR is the brand name of a generation of Straight-4 engines engineered and built by the Mazda Motor Corporation from 2001 to the present. MZR stands for MaZda Responsive". The MZR generation includes gasoline and diesel powered engines ranging in displacements from 1.3L to 2.5L.All gasoline-powered MZRs feature an all-aluminum block construction with iron cylinder liners.