"It's not a real Porsche." Or is it?
There have been a couple of times where the future of the iconic Porsche 911 balanced on a knife-edge. One of those was in the early 1970s when Porsche's management, particularly managing director Ernst Fuhrmann, believed the niche 911 sports car was approaching the limits of its potential. That's not a prediction that has aged well, but the 911 did have a sales slump in the mid-1970s, which helped Fuhrmann's case that Porsche needed to prepare a new car for the company to survive and keep moving forward. He believed that Porsche needed to look towards high-end grand touring vehicles with conventional engines rather than small unconventional sports cars with unconventional engines and unconventional placements. Never mind that Porsche had defined the sports car market with the 911 and had, so far, built its customer base on that fact.
At the top of the new range, Fuhrmann wanted a luxury sports coupe that would compete with homegrown vehicles from Audi and Mercedes, and cement Porsche's place in the lucrative US market. Fuhrmann had been thinking ahead and, with Ferdinand Porsche's backing, had kicked off a study in 1971. The 928 would be a clean-sheet design, which meant Porsche was heading into new and unknown territory.
As the 928 was a new design, Porsche didn't have a vehicle to build upon, so the design department did what automakers still do to this day - bought some models from the competition and turned them into development cars. After consideration, Porsche knew that a new V8 would power the new car, it would be front-engine and rear-wheel drive, have two doors, and a 2+2 seating arrangement. For reference, the 928's development started with a Mercedes-Benz SL codenamed V1, and was mainly used to develop the 928's transaxle until Porsche fitted its new 4.5-liter V8 and a prototype front axle. The second testbed codenamed V2 was an Opel Admiral rebuilt with a prototype chassis while retaining the sedan's drivetrain. It was V3 where the 928 started to truly take shape, and Porsche used Audi models to start the finalization process.
As the 928 was to be a grand touring model and its flagship car, Porsche wanted a high-displacement V8. The idea of a V10, based on an Audi five-cylinder unit, which was based on a Volkswagen engine, was quickly nixed. Porsche knew there would be speculation and excitement about a new Porsche model if that route was chosen. Instead, Porsche's engineers came up with the all-alloy M28 V8 engine and ensured it could draw good airflow despite the 928 having a low hood. When finalized, the first Porsche 928 had a 16-valve, 4.5-liter V8, making 240 hp in Europe and around 219 hp in North America.
Porsche also focused on handling as well as power, starting off with a transaxle combining the transmission, axle, and differential into one unit and allowed the 928 to have a 50/50 front to rear weight ratio. The transmission part was either a five-speed dog leg manual transmission or a three-speed, then four-speed in the mid-1980s, automatic transmission.
Although the Porsche 928 was designed as a package, the smaller, four-cylinder, water-cooled 924 launched first. Intended to replace the entry-level 914, the 924 arrived in the 1976 model and instantly started selling. Enthusiasts loved its performance and styling, and it became a much-needed source of revenue for Porsche. It also laid the groundwork for the more powerful flagship model, which arrived in 1978. Unlike GT cars from other high-end automakers, the 928 had a hatch at the back rather than a deck lid with big slanted windows emphasizing its aerodynamic shape. The big taillights carved into the rear also set it apart, along with the beltline bulging out to add to the 928's low, squat stance. Pop-up headlights kept the front smooth during the day.
The body was ahead of its time in aerodynamics, and most of it was made of aluminum alloy. However, there were several materials that needed to be painted, so Porsche had to develop a new paint that would bond to all the surfaces without changing the color. Despite being a larger vehicle, the 928 only weighed 3,196 pounds - more than the much smaller Porsche 911 at the time (2,469 pounds), but much less than the Mercedes-Benz SL (3,955 pounds).
The Porsche 928 wasn't an instant success, selling moderately well in its first year, and at least partly due to the 911 still being on sale and selling at almost a third of the price as the 928. Despite snobbery from people that thought Porsche should only ever make the 911, it was generally well-received by enthusiasts and journalists. One common commendation was that the 928 was a much more comfortable car and a safer vehicle to drive fast than the much trickier 911.
In 1980, Porsche launched the 928 S in Europe with the 4.5-liter V8 enlarged to 4.7 liters and added front and rear matte-black polyurethane spoilers. The US got a competition package in 1981; then, the 928 S arrived in 1983 to replace the standard 928. It made 234 hp and was now modified to use a four-speed transmission. It also gained larger wheels in a different style to the original five-hole design. In 1984, Porsche introduced the Bosch EZF ignition system to increase engine compression and torque. Porsche now advertised the 928 S with its 146 mph top speed as "the fastest street-legal production car sold in the US." The 928 S model got even faster in 1985 for America, though with power rising to 288 hp in the US and 300 hp in Europe. The new technology then filtered through to other markets.
While Porsche had realized dropping the 911 would have been a huge mistake, the 928 wasn't one. In the mid-1980s, the 928 sold well, and by the end of its run in 1995, Porsche had built 61,056 in total. But by 1980, Porsche's management knew that axing the 911 would have been a terrible idea, and Ernst Fuhrmann was asked to resign. He was replaced by German-American Peter W. Schutz.
Power rose again with the 1986 model year when Porsche grew the V8 engine to 5.0-liters, but didn't make significantly more power until the 928 S4 variant appeared for the 1987 model year. The good news for America is that the S4 made 316 hp, the same as everywhere in the world except Australia, where it made 296 hp. To hammer home just how fast the 928 was, Porsche sent a pre-production 928 S4 to Bonneville with American racing driver Al Holbert to set a new speed record. The car was recorded between two runs at 171.926 mph, making it the fastest non-turbocharged production car in the world.
After the S4 introduction, major updates were few and far between until the dogleg manual transmission-only 928 GT debuted in 1989. It was a sporty version of the S4, featuring a more aggressive suspension setup, an upgrade in power to 300 hp, and special Club Sport wheels. The S4 also brought a significant styling update. It was now a world car, with the only major differences between countries being the instrumentation or bumpers and lighting to suit individual country's legislation. For 1990, Porsche made its 0-100% variable ratio limited-slip PSD (Porsche Sperr Differential) system standard on S4 and GT models.
During the 1991 model year, Porsche ended production of the S4 and GT variants of the 928 to make way for the final model. The 928 GTS made its way from the factories at the end of the year, but didn't make it to America until 1993. It came with big flared fenders to cover the 17-inch wheels and wider track, bigger front brakes, and the engine displacement increased to 5.4-liters. The 928 GTS made 350 hp, cleared 60 mph in just over five seconds, and topped out at over 170 mph. What Porsche wasn't advertising, though, was the price. Fully loaded, a GTS could clear the $100,000 price point in 1995. That made it one of the most expensive cars in the world in the mid-1990s, which hurt sales despite it being one of the fastest cars in the world.
Popular opinion, particularly from the clickbait community, seems to be that it was a mistake. However, in reality, the mistake would have been for Porsche to retire the 911 and the automaker didn't do that. The 928 and it's sibling, the 924, sold well for Porsche and opened the automaker to new markets and offered existing 911 owners something more comfortable to park next to the dedicated sports car in the garage and use as a daily driver. That's something Porsche later worked out was a lucrative approach when it did the research. The automaker realized the majority of Porsche owners also owned an SUV - which paved the way for the Cayenne, and that was the vehicle that ultimately saved Porsche from being absorbed by Mercedes or going bankrupt.
Another reality is that Porsche was never going to survive, let alone thrive, on 911 sales alone. The premise that the 911 was at the end of its development was incorrect, but the realization Porsche had to expand its lineup was on the money. The 928 was the start of that, and it's that thread of Porsche's story that has led to the Cayenne, Boxster, Macan, Panamera, and Taycan model lines. If it weren't for those, the 911 would have ceased to exist decades ago. No matter how you dice it, it's hard to argue that the 928 was a failure with a straight face.