Despite the fact that it was originally intended to be a VW-badged sports car, the 924 was a solid money maker that helped keep Porsche afloat.
It was obvious by 1970, after just one year of sales, that the Porsche 914 was never really going to take off in any significant way. The car which was picked as a replacement would end up being even more controversial than the 914, but more successful as well. It was originally designed as a Volkswagen sports car, but ended up wearing Porsche badges. Purists hate it, but without it, Porsche and their beloved 911 might have died off entirely by the end of the Seventies.
Porsche had been pretty thoroughly screwed over by Volkswagen in 1968 when it came to the 914, stemming from a change of leadership at VW. VW's then-new boss Kurt Lotz had charged Porsche much more than originally anticipated for its contributions to the 914, and therefore made the car a far less appealing product. But Volkswagen saw profits plummet under Lotz's watch, and he was replaced in 1970 by Rudolf Leiding. Leiding was a sports car enthusiast, and his desire to bring more sportiness to the brand lead to renewed cooperation with Porsche.
Porsche would end up taking over quite a bit of VW's design work, and this worked out incredibly well for VW, resulting in both the Passat and the Scirocco. But the Scirocco wasn't the car which VW had originally planned to build. The car that would become the 924 was in the works to take on this role first, but VW ultimately decided that the Golf-based Scirocco was the more practical (read as "cheaper") option. This left the 924, and the huge amount of money which had already been spent on development, in limbo until Leiding left VW in 1974. Porsche seized this opportunity to both save its design and find a replacement for the 914, and bought the design back.
More development was still required, but the 924 would break cover in 1975 as a 1976 model. The 924 was actually the first Porsche to hit dealerships with a water-cooled engine, a front-mounted engine, a non-boxer engine, or an automatic transmission. Some would prefer not to bestow these "first" honors on the 924 for a couple of reasons. First, the 928 also had all of these things and was actually in development first, even if it hit dealerships a year later. Second, unlike the 914, which was designed to be both a Porsche and a VW, the 924 had been designed only as a VW, with the change in badging happening at the last minute.
This then made its status as a "real" Porsche questionable.The engine that was use was one designed by VW and built by Audi. It is a popular myth that it was designed for the VW LT van and then later appropriated by other brands, but its first appearance in a vehicle was actually the Audi 100. Still, the fact that the engine was used in a van didn't help the 924's image, and did the fact that it was later used in the AMC Gremlin. This 2.0-liter four-cylinder produced 95 horsepower, but was bumped up to 110 in 1977. Probably the most significant change to the 924 happened in 1978, with the introduction of the 924 Turbo.
This was a 924 that was much more Porsche, and the engine produced 170 horsepower, bumped to 177 in 1979. Surprisingly, with its lower weight, the 924 Turbo produced performance figures which were very similar to the much more expensive contemporary 911 SC and its 180 horsepower. The Turbo would even evolve into the 924 Carrera GT and 924 Carrera GTS, homologation versions of the car which produced 210 and 245 horsepower respectively. The full-on race version was the 924 Carrera GTR, which produced 375 horsepower and would grab a 6th place overall finish at the 1980 24 Hours of Le Mans.
The 924 was joined in the Porsche lineup by the 944 in 1982. This was a car built on the 924 platform, but originally intended to replace the 924. But the 924 was still selling strong, and instead the 944 simply slotted in just above the 924 until becoming a total replacement when the 924 was killed in 1988. It had come into its own, particularly with the Turbo model by then, but was still largely obsolete. In 1984, VW decided to retire the 2.0 engine, and what with the 944 already in production, it was believed that Porsche would simply drop the car from the lineup.
But instead they simply used a detuned version of the 944's 2.5-liter engine, 150 horsepower to the 944's 160, and sold it as the 924S. In the end, Porsche sold more than 150,000 units of the 924. It might have only ended up in the lineup as a fluke, but it was an unquestionable success. It turned out to be just the right car at the time, no matter what the purists have to say about it.