The Porsche 989 was the prototype of a four-door coupe by Porsche from the year 1988. This prototype never went into series production.
Due to the good sales of the Porsche 928 was considering to make a further sporty touring vehicle at Porsche. This vehicle should be suitable for everyday use alternative to the existing 928 with four doors. The development chief Dr. Ulrich Bez, replaced in 1988 by BMW, Porsche, should implement the requirements in the development project. These were that the new vehicle be luxurious and comfortable, while still a sporty character, similar to the vehicles from Mercedes and BMW should have.
The prototype had a newly developed front engine and a rear wheel drive. The performance of water-cooled V8 engine was (300 hp ) at about 220 kW. The capacity should be 3.6 to 4.2 liters. The wheelbase of the base platform was 2,826 mm.
The vehicle design was designed by Harm Lagaay and already contained a number of stylistic features that have been taken up in later drafts of the vehicle Porsche 993 and 996. In detail, these were the wishbone suspension and the headlights of the Porsche 959, which were later used in the 993. Also, the lines of the body was later elected the 996 similar to the 989.
According to DM 600 million development costs, Porsche AG of Bez separated in September 1991; the project 989 finally ceased in January 1992. The price for a sedan were estimated with 160 to 170 thousand DM. The only prototype was dismantled, according to Porsche. The main reasons for quitting the development of a four-door sports sedan was the reduction in sales of the 928, the general decline in sales in the years 1989 to 1991 and a forecast of development costs that exceeded the budget planning by 50% and up to the planned launch in mid -1990 to one billion Mark was estimated in the case of a continuation of the project. In this situation, the risk of the development project were rated higher than the benefits for the company Porsche; the then CEO Arno Bohn had left the company in 1992.
Predecessor of this 989 was an extended two doors prototype of the Porsche 911, as well as the prototype of the 989 unique. As the successor of the Porsche 989, the Porsche Panamera can be considered, which is produced since 2009. First four-door production model of Porsche was the Porsche Cayenne - not as a sport sedan like the 989, but as an SUV.