The Porsche 924 had originally been a project of VW-Porsche a joint Porsche/Volkswagen company created to develop and produce the 914 which was sold in Europe as both a Porsche and a Volkswagen. In 1972 a replacement for the Volkswagen version of the 914, code named EA-425 began development. The model was to be sold as an Audi as part of the VW-Audi-Porsche marketing arrangement.
Although testing had begun in the Spring of 1974 Volkswagen decided to cancel the program due to the expense of production as well as the feeling that the recently released Volkswagen Scirocco would fill the sports coupe sufficiently. At the time Porsche was considering introducing their own water-cooled front engine 2+2 coupe to replace the 912E and their model of 914 and Volkswagen's cancellation provided an opportunity. Porsche purchased the design and the finished development with an Electronic Fuel Injection system. The vehicle drove and handled exceptionally well and received positive reviews, but was criticized for the Audi-sourced 2-litre engine; Later in 1979, Porsche introduced a Turbocharged 924 to increase performance, but the price was considered too high for the time, which hampered sales. Rather than scrap the design, Porsche decided to develop the 924, as they had with generations of the 911; although model numbers would change, the 924 would provide the basis for its replacement.
Porsche re-worked the platform and abandoned the Audi engine, installing in its place its own freshly designed all-alloy 2.5-litre straight-4 engine, bore 100 mm (3.9 in), stroke 78.9 mm (3.1 in), that was, in essence, half of the 928's 5.0-litre V8, although very few parts were actually interchangeable. Not a natural choice for a luxury sports car, a four-cylinder engine was chosen for fuel efficiency and size, because it had to be fitted from below on the Neckarsulm production line. To overcome the unbalanced secondary forces that make other four-cylinder engines feel harsh, Porsche included two counter-rotating balance shafts running at twice engine speed.
Invented in 1904 by British engineer Frederick Lanchester, and further developed and patented in 1975 by Mitsubishi Motors, balance shafts carry eccentric weights which produce inertial forces that balance out the unbalanced secondary forces, making a four-cylinder engine feel as smooth as a six-cylinder. The engine was factory-rated at 150 hp (112 kW; 152 PS) in its U.S. configuration. Revised bodywork with wider wheel arches, similar to that of the 924 Carrera GT, a fresh interior and upgrades to the braking and suspension systems rounded out the major changes. Porsche introduced the 944 for MY 1982 to great anticipation. In addition to being slightly faster (despite having a poorer drag co-efficient than the 924), the 944 was better equipped and more refined than the 924's, it had better handling and stopping power and was more comfortable to drive. The factory-claimed 0-60 mph time of less than 9 seconds (8.3 seconds according to "Porsche the Ultimate Guide" By Scott Faragher). The factory-claimed top speed of 130 mph (210 km/h) was also pessimistic, Autocar having verified a top speed of 137 mph (220 km/h). The car had nearly even front to rear weight distribution (50.7% front/49.3% rear) thanks to the rear transaxle balancing out the engine in the front. This gave it very balanced, predictable handling at the limits of adhesion.
Source: Wikipedia, 2013