Porsche's Engine Evolution: Beyond the Flat-Six

The very essence of a Porsche has, for many enthusiasts, been intrinsically linked to the iconic rear-engined, air-cooled flat-six. This configuration, synonymous with models like the legendary 911, has defined the brand's identity for decades. However, to assume this has always been the sole philosophy in Zuffenhausen would be to overlook Porsche's rich and sometimes surprising engineering journey. The very first Porsche, born in 1948, was a mid-engine design, a layout echoed in many of Porsche's revered sports racers such as the 550 Spyder and the 718 RSK. This historical precedent meant that when a mid-engine production car, the 914, entered the Porsche line-up in 1970, it wasn't an entirely radical departure. Yet, the engine had yet to migrate from its rearward perch to the front, a significant shift that would occur a few years later.

A New Direction: The Transaxle Era

The year 1972 marked a pivotal moment in Porsche's history, a period of significant internal restructuring. Disagreements within the Porsche and Piëch families regarding the company's day-to-day operations led Ferry Porsche to decree that no family members would be directly involved in the operational management of Porsche AG. This ushered in a new management structure and, consequently, a distinct change in the company's strategic direction. While Ferry Porsche remained on the Board of Directors, his direct influence on operational decisions waned. He himself reflected in his 1989 memoirs, "This means that all my work bears his imprint, the result of a deep feeling of almost innate compatibility. In 1972, when the entire family withdrew from the company, the decisions taken by the new management encroached so much upon the company’s whole philosophy that they led to fundamental changes."

This new management team embraced the transaxle principle, a design that places the engine at the front of the vehicle with the gearbox integrated into the rear axle. While this was a reversal of Porsche's established rear-engine dogma, Ferry Porsche noted that the concept wasn't entirely novel to him, having been employed by his father in a Daimler racing car. Nevertheless, it represented a definitive break from earlier design principles, a departure from his father's direct influence.

This bold new path led to the development of the 924, a car that would become Porsche's first liquid-cooled, front-engine sports car. Introduced for the 1976 model year, the 924 was, to a degree, a product of collaboration with Volkswagen. Porsche AG had originally developed the 924 for Volkswagen as a more affordable successor to the 914 in Europe. However, when VW decided against production, partly due to the 1973 global energy crisis, Porsche AG took over the project. The energy crisis, with its ripple effects including fuel economy mandates and economic downturns, profoundly influenced automotive design and consumer preferences.

The Four-Cylinder and the Phantom Five-Cylinder

Porsche's decision to develop a four-cylinder engine for the 924, utilising an existing VW design, was a strategic move to economise on manufacturing costs. Ferry Porsche later admitted that had the forthcoming Audi five-cylinder engine been available at the time, it would likely have been the chosen powerplant. This tantalising 'what if' highlights a missed opportunity for a unique Porsche engine configuration.

The "building-block principle" (kastenprinzip) adopted by the new management dictated the development of both four- and eight-cylinder engines. This led to two distinct models: the 924, designated for the four-cylinder, and the 928, intended for the eight-cylinder. Interestingly, Ferdinand Piëch, Ferry Porsche's nephew, then at Audi, suggested combining two of Audi's newly developed five-cylinder engines to create a 10-cylinder engine for the 928. Had this come to fruition, Porsche would have beaten Dodge by over a decade in introducing a multi-cylinder sports car. However, Porsche opted to develop its own V8 and design the entire car in-house, keen to distance itself from too close an association with Volkswagen-Audi.

The 924: A Porsche for a New Audience

While developed concurrently, the VW-Audi-based 924 premiered a year before the 928. Its assembly at Audi's Neckarsulm plant further fuelled the perception among some enthusiasts that it wasn't a 'true' Porsche. However, this car was engineered for a new market and a new buyer – a Porsche for the non-traditional Porsche enthusiast. As Ferry Porsche observed, "...with the new philosophy and the variants that have emerged from it we have found our clientele."

The 924's driveline and suspension were largely derived from off-the-shelf VW-Audi components, meticulously modified and redesigned by Porsche engineers at Weissach. This approach made the 924 a more diversified product compared to earlier Porsches like the 356 and 914, which relied heavily on VW components. The suspension featured parts from the VW Super Beetle, Scirocco, and the Type 181 military vehicle. The engine and transaxle were based on the Audi 100 design. A notable departure from Porsche tradition was the use of rear drum brakes, a compromise dictated by the VW components, whereas even the 914 had offered four-wheel disc brakes.

Styling was a critical aspect, with chief stylist Tony Lapine setting guidelines that ensured the 924 would look unmistakably like a Porsche, despite its front-engine layout and the absence of a traditional grille. Head stylist Harm Lagaay adopted a solution similar to Sergio Pininfarina's on the Ferrari Daytona, featuring a smooth front fascia with concealed headlights and air intakes positioned lower down. Despite some initial criticisms of its interior materials, the 924 was generally well-received for its handling and performance, attracting a new demographic of buyers.

The 928: A Bold Step into Luxury GT Territory

In stark contrast to the 924, the 928 was conceived as a high-performance luxury GT, targeting buyers of models like the Mercedes-Benz 450 SL. Porsche's decision to develop the 928 was significantly influenced by evolving US regulations and market trends. The US was Porsche's primary market, and the company was concerned that rear-engine, air-cooled designs might not meet future safety and emissions standards. Helmut Flegl, Porsche's Director for Research and Sport, recalled the anxiety: "We knew if these new rules came to life, we would have no car we could sell in the United States! It was then we knew we must make a front-engine car…"

The 928 was a complete departure, powered by a liquid-cooled V8 and designed entirely in-house, containing no VW or Audi parts. It was, in many ways, Porsche's first truly independent sports car. While purists viewed it as an aberration, it was a bold statement and a competitive alternative to the 911, a move into uncharted territory for the company.

Ferry Porsche later lauded the 928's success, stating, "The 928 and 928 S are now outstanding cars with better road-holding and more powerful brakes than the 911." The 928's advanced engineering, including its all-aluminium engine, extensive use of aluminium alloy in the bodywork, and transaxle layout, set new benchmarks for luxury GTs. The innovative Weissach rear suspension, with its toe-correcting characteristics, offered a precursor to four-wheel steering.

Key Porsche Models and Their Engine Configurations:

The Five-Cylinder Question: A Missed Opportunity?

The question of whether Porsche has ever produced a five-cylinder engine is a nuanced one. While the company did not officially produce a five-cylinder model for its road cars, the Audi five-cylinder engine was a critical factor in the development of both the 924 and the 944. The 924 initially used a VW-derived four-cylinder, but Ferry Porsche's comment about using the Audi five-cylinder if available is significant. Later, the 944, which evolved from the 924, effectively utilized a sophisticated four-cylinder engine that was, in essence, derived from half of Audi's 10-cylinder project (two five-cylinders). This means that while not a pure five-cylinder in the Audi sense, the 944's engine shared a common ancestry with Audi's five-cylinder technology.

The development of the 928 also involved a potential five-cylinder connection. Ferdinand Piëch's idea to combine two Audi five-cylinder engines to create a 10-cylinder powerplant for the 928, though ultimately rejected in favour of a Porsche-designed V8, underscores the influence of the five-cylinder configuration within the broader Volkswagen Group at the time. Therefore, while Porsche never officially marketed a 'five-cylinder Porsche', the engine type played a crucial, albeit indirect, role in shaping the brand's front-engine models.

Evolution and Legacy

The 928 remained in production for 18 years, evolving through five series: 928, 928 S, 928 S4, 928 GT, and 928 GTS. Each iteration saw improvements in engine power, luxury, and technology, including the introduction of anti-lock brakes (ABS) and electronically controlled limited-slip differentials. The final 928 GTS, with its 5.4-litre V8 producing 345 horsepower, was a testament to the model's continuous development and its status as a formidable luxury high-performance automobile.

Despite the success and innovation of the front-engine models like the 924, 944, and 928, the 911, with its enduring rear-engine, flat-six configuration, ultimately remained the heart and soul of Porsche. The US regulations that had prompted the shift to front-engine designs did not, in the end, legislate the 911 off the road. The front-engine Porsches, while successful in their own right and crucial for the company's survival and expansion, eventually receded as the 911 continued its unparalleled trajectory.

If you want to read more articles similar to Porsche's Engine Evolution: Beyond the Flat-Six, you can visit the Engines category.