In 1905, the Swiss engineer, Dr. Alfred Büchi, filed the first ever patent for a turbocharged piston engine. The fundamental principle, now a century old, remains unchanged to this day: to use the energy latent within the exhaust flow from the engine to increase overall performance.
The first turbocharged engine was built in 1910 by the firm of Murray-Willat. The concept was embraced by the aviation industry, which required an effective means of compensating for the loss of power caused by reduced oxygen levels during high-altitude flight. Porsche was among the first to recognise other benefits of the technology, including higher performance potential from relatively small displacement engines. This would lead to the development of powerful new engines with very modest dimensions and weight.
The basic principle of a turbocharged engine is to use the exhaust gas flow to drive a radial turbine which in turn drives a compressor in the air intake tract. The rotation of the compressor generates a higher intake pressure, thereby delivering a greater amount of oxygen to the engine. With more oxygen available, more fuel can be burnt, and higher performance can be achieved. The density of the air can be further increased by cooling it prior to combustion. The first ‘intercooler’ device on a production Porsche appeared in 1977 on the 911 Turbo 3.3.
The second 911 Turbo, launched in 1977, developed 300 bhp from a 3.3-litre intercooled engine. Brake performance was similarly enhanced, combining four-piston aluminium fixed calipers with
cross-drilled discs. In 1993, Porsche launched the final 911Turbo to feature dedicated rear-wheel drive. Based on the Type 964 platform, it used a 3.6-litre engine to achieve a major boost in output to 360 bhp. Its Type 993 successor, launched in 1995, set a range of new benchmarks in supercar performance.
All-wheel drive provided greater active safety as well as better driving dynamics. The system also had a rear-axle bias that retained the familiar Porsche handling characteristics. Twin exhaust turbochargers offered better response and a more harmonious build-up of power.The last 911 Turbo to have an aircooled engine, it offered maximum output of 408 bhp from a 3.6-litre displacement. The first water-cooled 911 Turbo, the Type 996, made its debut in the year 2000. Also equipped with all-wheel drive, it used VarioCam Plus to achieve a major improvement in all-round fuel economy. The engine capacity remained at 3.6 litres, while output rose to 420 bhp for a maximum speed of 305 km/h (190 mph). The Type 996 model was the first 911 Turbo with the option of Tiptronic S transmission.
The subsequent launch of the Turbo S version saw a further rise in output to 450 bhp. Now, the evolution of this remarkable car has reached a new pinnacle of achievement. Over the following pages, we will explore every aspect of the new 911 Turbo.
The first Porsche racing car to feature turbocharged power made its debut in the early 1970s. The 12-cylinder engine in the legendary 917 used a twin turbo system to achieve a colossal 1,000 bhp. In 1972, the 917/10 with 5-litre turbo engine claimed the North American CanAm championship. In the following season, the 917/30, developing 1,100 bhp from a 5.4-litre unit, became the most powerful racing Porsche of all time.
This invaluable race experience inevitably found its way into our production road car development. Just one year later, in 1974, the 911Turbo was born. Preceded as it was by the 1973 oil crisis, it was considered a bold undertaking by Porsche. As history would show, it was the first of many surprises in the evolution of this legendary car. The original 911 Turbo featured widened wheel arches as well as specially developed front and rear spoilers. These major aerodynamic refinements were essential requirements given the increased engine performance. Developing 260 bhp, the first 911 Turbo could reach 100 km/h (62 mph) in as little as 5.5 seconds. Maximum torque output of 343 Nm was unprecedented in a 3-litre engine. This exceptional performance necessitated a new gearbox design featuring specially reinforced gears. Thus began a new type of Porsche that would soon acquire mythical status.
|Engineering the new 911 Turbo...|