Porsche have been romancing the idea of a four-door performance sedan long before the Panamera came to be. The original idea actually came around 1982. At that point, Porsche had already started moving towards more luxurious models. The 928, for example, was much more of a gran-tourer than a proper sports car – that was the 911’s occupation. Although the 989 never made it to production, its development involved some interesting ideas, as well as thinking “outside the box”, which we are now sharing.

The idea of the 989 came thanks to the 928

Porsche is typically associated with making incredible sports cars. It has been so for more than half a century. Although the rear-engine 911 is their pride and joy, at one point, the company was very serious about abandoning the rear-engine layout in favor of the more conventional FR (front-engine, rear-wheel-drive) layout.

When the 928 came out in 1977, it was Porsche’s first step towards luxury performance vehicles. The strong sales were followed by the idea of further exploring the luxury car niche. After a couple of unsuccessful attempts at turning the 928 into a proper four-seater (one of which involved AMG), Porsche decided to work on a fully-fledged performance sedan.

Actual development started in 1988

The idea of Porsche’s very own performance sedan was explored as early as 1982. However, at that time, Porsche was still stretching the capabilities of the 928 platform, attempting to make a longer shooting-brake version of the car that would feature four normal seats. Due to the inability to make the chassis stronger, the project was eventually dropped in 1987. One year later, development of the 989 commenced, under the supervision Porsche engineer Dr. Ulrich Bez.

It intentionally resembles the 911

The 911 is the German company’s crown jewel. It is, quite simply, the definitive Porsche. The design team was commissioned to make “a Porsche for four” that would still resemble the 911. Dutch automotive designer, Harm Lagaay. He returned to Porsche in 1989, as head of the “Style Porsche” department in Weissach, where he worked till 2004.

Before that, he worked as a Chief Designer for Ford (1977) and later BMW (1985). Among his creations are the BMW Z1 and many Porsche models, like the 968, Boxter, 911 (993), Cayenne, 911 (996), and the Carrera GT.

The 989 aimed straight at the BMW M5 and Mercedes 500E

Porsche prides itself on being a sports car manufacturer. So when development started, BMW M5 and Mercedes 500E were the benchmarks. The Porsche 989 was meant to be lighter, more luxurious, and more powerful. It was specifically developed to beat them in every measurable way and, at least on paper, the prototype was.

It was never meant to have a flat-six engine

The 989 may have been styled to look like a 911, but that’s where the similarities end. While the 911’s power always came from a flat-six air-cooled (still) engine, the 989 was always intended to have a V-8. At the earlier stages of development, the car was supposed to receive a 3.6-liter normally-aspirated V-8 with around 300 horsepower.

However, it ended up with a bigger 4.2-liter 80-degree V-8, producing 350 horsepower. The engine had a lot in common with the Audi unit, used at the time, but was not identical to it. Supposedly, an even more powerful version of the engine was considered.

A Mercedes W124 was part of the development process

Most of you probably remember the Mercedes W124 500E. It was Porsche that made the Mercedes V-8 fit inside its engine bay, thus creating what is considered, by man, the ultimate V-8 performance sedan. This was due to the reason that, just like the Porsche 928, the 989 used a front-mounted V-8. Since Porsche didn’t have its own performance sedan, a W124 Mercedes 500E test mule was used to simulate the handling characteristics. Moreover, the W124 "Merc" and Porsche 989 were very close in terms of size.

It was decided against a rear-engine layout because it wasn’t luxurious enough

How many rear-engine performance sedans do you know of? My point exactly! Porsche quickly decided against the rear-engine layout, but not for practicality or weight-distribution reasons. They wanted the 989 to compete against the likes of BMW M5 and Mercedes 500E (which Porsche created) – both front-engine, rear-wheel-drive sedans.

More importantly, the rear-engine layout would have associated the luxurious Porsche with the not so upscale (by Western standards) Tatra 613, which had rear-mounted, air-cooled 3.5-liter V-8.

It was decided against a rear-engine layout because it wasn’t luxurious enough

How many rear-engine performance sedans do you know of? My point exactly! Porsche quickly decided against the rear-engine layout, but not for practicality or weight-distribution reasons. They wanted the 989 to compete against the likes of BMW M5 and Mercedes 500E (which Porsche created) – both front-engine, rear-wheel-drive sedans.

More importantly, the rear-engine layout would have associated the luxurious Porsche with the not so upscale (by Western standards) Tatra 613, which had a rear-mounted air-cooled 3.5-liter V-8.

It would have been the first entirely water-cooled Porsche

Of course, that title goes to the 996-generation 911, although the 959 had a water-cooled head. The reason why the 989 was water-cooled was not because of Porsche’s desire to evolve its drivetrains, but because the Tatra 613 was also water-cooled. An upscale car needed to have the most sophisticated technical solutions available and water cooling is simply better than air cooling, albeit more complex.

Lighter and more powerful than the 500E and M5

Had they made the Porsche 989, it would have had a much better power-to-weight ratio than both the Mercedes 500E and BMW M5. The final and fully-functioning Porsche 989 had a curb weight of 3,465 pounds (1,572 kg), while the BMW M5 E34 tipped the scales at 3,680 – 3,880 pounds (1,669 – 1,760 kg). The Mercedes on the other hand weighed 3,680 – 3,880 pounds (1,669 – 1,760 kg).

Power-wise the Porsche had them both. The BMW M5 E34 came with a 3.6 and later a 3.8-liter normally-aspirated inline-six, rated at 311 to 340 horsepower. The Mercedes’ 5.0-liter DOHC V-8 produced 322 horsepower. The Porsche 989 could also go up to 178 mpg (273 km/h) – far more than the M5’s 160 mph (257 km/h) and the 500E’s 156 mph (252 km/h) top speed.

It was ready to hit the showrooms

The Porsche 989 wasn’t just a concept show car. As early as 1989, a fully functioning car was ready. It had a 111.3-inch (2,826 mm) wheelbase and an FR (front-engine rear-wheel-drive) layout, as it was always intended.

The Porsche 928 killed the idea

Porsche’s idea of a four-door performance sedan was heavily dependent on the popularity of the 928. However, you can only produce a car for so long. The 928 may have been a sales hit when it came out, but by the early 1990s, the sales figures were a disaster. Despite the 928 carrying on until 1995, things weren’t looking good for the 989.

After crunching some numbers, it was decided that the 989 project would not be economically sound for the struggling company. Development was halted in 1991 and the project was completely abandoned in January 1992.

Some 989 design cues made it to production

Porsche’s idea of a 1990s performance sedan may have died, but some 989 design elements made it to production. The taillights and overall rear-end design can be seen on the Porsche 996. Porsche’s idea of a four-door performance sedan was finally realized in 2009, with the Panamera.