Thirty Years of the Porsche 911 Turbo

Press Release

Putting on the Pressure - for Three Decades (short story)

It was at the 1974 Paris Motor Show that Porsche presented a high-performance sports car setting an outstanding new benchmark in terms of acceleration, torque, dynamic performance, and brake power: the 911 Turbo 3.0. Maximum output of this outstanding sports car was 260 bhp from three litres engine capacity. Achieving a top speed with this power of 250 km/h or 155 mph, the Porsche 911 Turbo 3.0 was for a long time Germany's fastest road-going sports car. A comparison with the current successor to the first Turbo, the Porsche 911 Turbo S in 2004, clearly shows, however, that the process of development never comes to an end: Maximum output of the current model is 450 bhp from 3.6 litres capacity, giving the car a top speed of 307 km/h or 190 mph.

The 911 Turbo had a particularly prominent friend and supporter right from the start: Professor Ferdinand ("Ferry") Porsche drove one of the Turbos from the very first series with chassis number 930 770 088 for a total of 8,200 kilometres until 16 June 1980. Ever since this very special model featuring a steel sliding roof, air conditioning, brown leather upholstery and further extras has been one of the outstanding exhibits at the Porsche Museum.

The original idea in 1974 was to build the first 911 Turbo in a production run of 1,000 units. But to put it mildly, this forecast was slightly off the mark, total production of the 911 Turbo from 1974 - 1989 amounting to almost 21,000 units.

Following a break in production of two years, the next Turbo powered by a 320 bhp 3.3-litre engine was launched in 1991, this time based on the 911 model series code-named the 964 within the Company. The next generation of the 911 Turbo (993 model series) introduced in 1995 again set new standards in the world of the sports car: The power unit of this model was based on the air-cooled 3.6-litre engine of the 911 Carrera and featured two turbochargers boosting output to 408 bhp at 5750 rpm. Another significant innovation was the introduction of all-wheel drive carried over from the 911 Carrera 4. Total production of this 993-series Turbo was 6,314 units.

The 996 version of the 911 Turbo introduced in the year 2000 maintained Porsche's all-wheel drive and bi-turbo technology. And it also introduced composite ceramic brake discs as a feature which has now been available for four years.

In its basic characteristics, the Turbo has remained unchanged for 30 years: Throughout all this time, the emphasis has been on exceptional power and performance combined with equally superior comfort and everyday motoring qualities - features which have characterised all models and versions over the years.

Fast, Dynamic, Comfortable (long story)

Particularly one of the cars on display at the Paris Motor Show back in 1974 aroused huge attention right from the start through its exceptional looks and visible features: The biggest eye-catcher was a large rear wing on the engine lid, perforated by ventilation slots and framed by a thick rubber "lip". And what lurked beneath this big rear spoiler made even the most experienced Porsche driver gasp for breath: A three-litre six-cylinder horizontally-opposed power unit with a turbocharger, 260 bhp maximum output, a top speed of 250 km/h or 155 mph, and the bite of thoroughbred racing machine. And that, basically, was what it was: The Porsche 911 Turbo was not only the fastest road-going German sports car, but also the forerunner to a genuine turbo boom.

And, most definitely, it was also a bold step into the future. While turbocharged engines were no longer that unusual in motorsport, only one manufacturer had attempted to introduce such an engine in a road-going car so far - and had suffered big problems in the process. The reason, quite simply, was that the high power provided by the turbocharger generally meant a significant reduction in engine life, making the engine very sensitive and making the car challenging - if not to say, difficult - to drive. In a nutshell, therefore, the turbo engine was regarded as hard - or even impossible - to handle.

The basic concept: a racing car for the road

Porsche's engineers, however, proved superior in their know-how and practical implementation of the concept: The original plan was to build a small series of Gran Turismo sports cars derived from motor racing and now legal for road use. Back then the GT regulations called for a production volume of 400 units. But since Porsche saw no way to sell that many cars to racing drivers, the Company decided to make the competition model street-legal, making only a few concessions to motoring comfort. The turbocharged engine was of course the heart of the new car from the very beginning: First, Porsche had already gained experience with this technology in the 12-cylinder 917/10 and 917/30 race cars developing maximum output of up to 1100 bhp. Second, the general feeling was that the 911 power unit originally introduced in 1983 with 130 bhp no longer offered adequate potential for a further increase in power and victory on the race track, without enjoying the benefits of turbocharging. Accordingly, while the normal-aspiration power unit of the RSR 3.0 upgraded for motorsport in 1974 developed maximum output of 330 bhp, the 911 Carrera RSR 2.1 raced in the same year developed 500 bhp with the help of a turbocharger.

With the minimum weight for GT racing cars being increased in spring 1974, Porsche saw the opportunity to build not a racing car in disguise, but rather a luxury high-performance sports car as the foundation for the racing version. So from March 1974 to the introduction of the new model in October of the same year, the new concept was converted into reality for the flagship within the Porsche range (fully homologated for the road, of course). To overcome the disadvantages of the turbocharged power unit such as inadequate power and acceleration at low engine speeds, Porsche introduced a concept of turbocharger pressure control by means of an exhaust gas by-pass valve previously only seen in motorsport. Benefitting from this sophisticated management concept, Porsche's engineers were able to suitably modify the dimensions of the turbocharger to build up more pressure at low engine speeds and thus develop extra torque in the process. To keep this more than ample power under control, Porsche's engineers used their extensive experience in motorsport also for the brakes, fitting the car with inner-vented disc brakes complete with aluminium brake callipers originally featured in the Porsche 917 racing car.

Instead of 400 cars, the objective Porsche now set itself was to build 1,000 units of the 911 Turbo 3.0. But this forecast soon proved completely inadequate, production of the 911 Turbo 3.0 featuring amenities widely recognised as luxurious at the time such as electric window lifts and a stereo cassette radio amounting to 2,876 units by 1977.

1977: the Porsche Turbo breaks the magic mark of 300 bhp

With deliveries of the Porsche 911 Turbo starting in spring 1975, nobody really believed that a car of this calibre might ever require even more power. But they were wrong! In 1977 Porsche introduced the 911 Turbo 3.3 powered by an even larger engine now, with the help of an intercooler, developing that magic figure of 300 bhp. Code-named the 930 model series, this sports car remains a legend to this day. Porsche's next major breakthrough came in 1982, in a process of ongoing development: Thoroughly optimising the fuel supply system, Porsche's engineers were able to significantly reduce fuel consumption while maintaining the same high level of power: Instead of 20 litres in city traffic (14.1 mpg Imp), fuel consumption was now just 15.5 litres (18.2 mpg Imp), the corresponding improvement at a steady speed of 120 km/h or 75 mph being 11.8 litres (23.9 mpg Imp) instead of 15.3 litres (18.5 mpg Imp) so far.

In 1987 the Coupé version was joined by a Targa and a Convertible. At an initial price of DM 152,000, customers received one of the fastest open cars in the world coming as a no-cost option with electrical operation of the roof. Just one year later, five-speed transmission replaced the former four-speed gearbox, close gear increments serving to keep turbocharger pressure even more consistent while shifting gears and improving acceleration from a standstill to 100 km/h by 0.2 seconds to 5.2 seconds.

By 1989 the Porsche Turbo became the fastest best seller in the German market, with sales amounting to almost 21,000 units hardly modified in their exterior design and appearance.

Following a break in production of two years, Porsche presented a new 911 Turbo in 1991: The 3.3-litre power unit now developed maximum output of 320 bhp, the new car being based on the 911 model series code-named the 964 within the Company and by the connoisseur. When Porsche modified this model in 1993, power was increased in the process, the 911 Turbo 3.6 now developing maximum output of 360 bhp.

1995: enhanced fuel economy setting a new standard in the sports car segment

Entering the 1994 model year, the 964 model series was replaced by the 993. But the new Turbo in the 911 model range took a bit more time coming, the next Turbo generation entering the market in 1995 and immediately setting a new standard once again: The power unit of this 911 Turbo based on the air-cooled 3.6-litre engine of the 911 Carrera and featuring two turbochargers developed maximum output of 408 bhp at 5750 rpm. Acceleration from 0 - 100 km/h came in 4.3 seconds, top speed was 293 km/h or 182 mph. The exhaust system featured two metal-based catalytic converters and four oxygen sensors. A significant contribution to superior environmental protection typical of Porsche to this very day was made by the on-board diagnosis system II (OBD II). Fitted worldwide in all 911 Turbos, this sophisticated system permanently supervises all components relevant to exhaust emissions, immediately detecting any defects and activating a warning light in the cockpit. As a result, the 993-series Turbo was lauded the world over for its particularly clean exhaust emissions.

Yet another outstanding innovation was all-wheel drive carried over from the 911 Carrera 4 in the interest of optimised driving behaviour, traction and stability on the road. In the same process Porsche's engineers re-designed both the front and rear end, adapting the side-sills to the wider wheel arches. The single-piece front end now came with even larger air scoops, yet another new development being the rear spoiler fixed in position. Air resistance was optimised by the air flow lip at the bottom of the front air dam and by improved flow conditions throughout the front end of the car as a whole, lift forces being reduced in the process to virtually zero both front and rear. Production of this version of the 911 Turbo amounted to 6,314 units.

Entering the year 2000: more power, greater economy

The current Porsche 911 Turbo (the 996 model series) - again featuring four-wheel drive and bi-turbo technology - is not only one of the fastest and most powerful sports cars in the world, but also won the title of the "World's Cleanest Car" when introduced in February 2000. The abbreviation "LEV" used above all in the USA stands for "Low Emission Vehicle" - and Porsche's extra-clean Turbo fulfils this strict emission standard in the same way as it complies with the EU 3 or D4 standards. Fuel consumption, in turn, has been reduced once again from the former model already widely lauded for its fuel economy by another 18 per cent to 12.9 litres/100 km (21.9 mpg Imp) in the composite EU cycle. And exhaust emissions are down by an equally impressive 13 per cent.

Improvements of this kind are made possible by four-valve technology, water cooling and, in particular, VarioCam Plus serving to adjust the camshafts and vary valve lift as required. Indeed, it is fair to say that VarioCam Plus combines two engine concepts in one, serving to reduce fuel consumption and exhaust emissions and improve motoring refinement all in one.

The catalytic converters are right behind the turbochargers, the first, smaller catalyst taking effect very soon after the engine is started cold. The main catalyst, in turn, is designed for optimum conversion of exhaust emissions with the engine at normal operating temperature. On-board diagnosis (OBD) checks, as on the 993-series Turbo, whether all components and functions relevant to exhaust emissions are working properly. OBD immediately detects even the slightest deviation from target figures by consistently monitoring exhaust emissions with electronic accuracy, any defects being reported by a display in the cockpit.

Ceramic brake discs available as an option

The current Turbo model stands out clearly from the other models in the 911 Carrera (996-series) range through its striking air scoops at the front. The rear end of the car, in turn, is characterised by a newly designed wing as well as the air intakes and outlets for the intercooler. The car's impressive specifications and performance data are 420 bhp maximum output, acceleration from 0 - 100 km/h in 4.2 seconds, and a top speed of 305 km/h or 189 mph. And since autumn 2000, the Turbo has also been available with composite ceramic brake discs.

Despite this ongoing process of development, the 911 Turbo has retained its character throughout three decades: Outstanding performance, supreme acceleration and superior luxury (five-speed automatic transmission, Tiptronic S, leather upholstery) as well as impressive quality and lasting value have enabled this dynamic sports car to become a genuine classic in the course of the last thirty years, a car which already today holds a unique position in the world of motoring.

Power Unit

More Air for More Performance

For a long time now, the word "turbo" has become a synonym in modern language for exceptional power and performance. And the Porsche 911 Turbo has contributed most significantly to this special meaning of a special word.

The principle of this technology is clear and straightforward: The exhaust gas flowing out of the engine accelerates a small turbine wheel to high speeds (up to 90,000 rpm, for example, on the first 911 Turbo back in 1974). Via a shaft, this turbine wheel drives a second rotor wheel forcing air into the combustion chambers. The more air gets into the cylinders in this way, the more oxygen is available and is able to burn together with the fuel. The obvious result is an increase in engine output. Hardly any additional components or mechanical functions are required for operating the turbocharger. Instead, the system uses the residual energy in the exhaust gas, giving it a fundamental benefit over a compressor applying the supercharging principle.

To build up adequate pressure at low speeds while not overtaxing the engine at high speeds, a by-pass valve maintains a stable pressure balance, ensuring that turbocharger pressure does not exceed the maximum limit allowed. While on the first Porsche 911 Turbo this limit was 0.8 bar, there was still a certain time-lag back then before the turbine responded. This, in turn, made the engine cut in with its extra power rather abruptly, leading to well-known expressions such as "turbo gap" and "turbo boom".

High torque

Turbocharged engines develop their maximum output at relatively low engine speeds. The first 911 Turbo, for example, reached its maximum power of 260 bhp at 5500 rpm. And this relatively low level of engine speed remains unchanged to this day, the current Turbo S entering the market in summer 2004 reaching its maximum output of 450 bhp at 5700 rpm. While a sports engine without turbocharging requires not only far higher speeds in order to develop the same kind of power, turbo technology offers the additional advantage of developing superior torque at low engine speeds: The Turbo S, for example, generates 620 Newton-metres or 457 lb-ft of torque between 3500 and 4500 rpm.

Up to 1995 the exhaust pipes from the two rows of cylinders on the flat-six power unit were merged to form one unit driving a common turbocharger. Then, starting with the 993 model series in 1995, two turbochargers - one for each row of cylinders - took over the function of building up the appropriate pressure. Today the appropriate technical layout and electronic management ensure a the right kind of engine response and give the driver perfect control of engine power on the current 911 Turbo, thus setting the standard for high-performance power units also in this respect.

Yet another feature makes the engine of the Turbo simply ideal for a luxurious Gran Turismo sports car: the turbocharger in the exhaust system acts as an additional silencer. This explains why turbocharged engines are exceptionally quiet, requiring only a small silencer to comply with strict noise limits.