The 2.2 and 2.5 are a family of inline-4 engines developed by Chrysler Corporation originally for the Chrysler K- and L-platforms cars and subsequently used in many other Chrysler vehicles. After its launch in 1981, it became the basis for all Chrysler-developed 4-cylinder engines until the Chrysler 1.8, 2.0 & 2.4 engine family was released in 1994. It was the first Chrysler engineered four cylinder engine since the Chrysler flathead four cylinder was discontinued in 1933. 2.2 The first version of this engine family was a normally aspirated unit. Developed under the leadership of Chief Engineer – Engine Design and Development Willem Weertman and head of performance tuning Charles "Pete" Hagenbuch, who had worked on most of Chrysler's V-8 engines and the Chrysler Slant-6 engine, it was introduced in the 1981 Dodge Aries, Dodge Omni, Plymouth Horizon and Plymouth Reliant, and was produced until 2000. The 2.2 has an undersquare bore and stroke, which gives it a displacement of . It is a siamesed engine: there are no coolant passages between cylinders. The bore spacing is , limiting the potential for increased bore diameter. All 2.2 engines have cast iron blocks, use a timing belt, and are non-interference engines. The earliest version used a two-barrel carburetor, but fuel injection was introduced in 1984 on both turbocharged and normally aspirated models (it is used on all 2.5 liter engines). Fuel injection was standard on some higher end models such as the Chrysler E-Class, Laser, and New Yorker, and the Dodge 600 and Daytona. In 1985 fuel injection became optional on the lower end models (Dodge Omni/Plymouth Horizon, Dodge Aries/Plymouth Reliant), eventually replacing the carbureted variant across the board. The initial carbureted 2.2 initially produced , but the output was increased to and . Later versions were fuel-injected and produced to and , and a High-Output version for the Dodge Charger produced and . Four series of turbocharged 2.2 and 2.5 liter engines were produced, normally referred to as Turbo I, Turbo II, Turbo III, and Turbo IV. The primary difference between these engines was the use of an intercooler (in all except Turbo I). The Turbo III, ironically developed after the Turbo IV, pioneered returnless fuel injection, and was coupled to high-performance, four-valve-per-cylinder heads, bringing from the 2.2 liter engine. The Turbo IV pioneered the use of variable nozzle technology to minimize lag. The 2.2 was made at Chrysler's Trenton Engine