Porsche 1985 MY: the 944 Turbo

Racing success with catalytic converter technology: Porsche's new high-performance sports car

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The 944 Turbo-Story

It was at Le Mans in 1981: for the first time, a 2.5 liter four-cylinder of the new generation competed in the toughest long-distance race in the world. The vehicle that Walter Röhrl and Jürgen Barth drove to 7th place in the midst of the superior competition had the camouflage designation 924 GTP. In reality it was a first test racing version of the future 944 Turbo. It turned out to be the most reliable car in the entire field and received the award for the shortest pit stop. Many a super powerful car that spent long idle times in repairs was rounded off by him.
Three years later, in June 1984, a 944 Turbo pre-production car started in the Nelson Ledges 24-hour race in Ohio / USA. This race, which is held on a grueling country road course, is reserved for series cars and series prototypes that meet the strict American road traffic regulations. This also includes the catalytic converter. Here, too, the 944 Turbo faced competition in terms of displacement and high performance, but the Baker / Busby / Knoop team won with a 40 lap lead in the trouble-free 944 Turbo. The drivers could listen to music on the radio on the way. Because this fastest car in the field was also one of the quietest.

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For Porsche's engine builder, "turbo" does not only mean an increase in the performance of racing cars, but also sophisticated power delivery in sporty road vehicles. The smooth-running, powerful 944 four-cylinder with counter-balancing shafts offered a new turbo concept in which high torque, economy and noise dampening are in the foreground. Achieving the desired driving performance - a top speed of 245 km/h and an acceleration from 0 to 100 km/h in 6.3 seconds - was the least of the problem, if only the racing engine had to meet the performance requirements of the road vehicle be reduced.
The catalytic converter concept was part of the development scope of the 944 Turbo from the start. The version with a catalytic converter had to complete the same long-distance endurance runs at top speed on a special route as the version without a catalytic converter. Both were designed for the same output of 162 kW (220 hp). In doing so, Porsche took the different situations in the area of exhaust gas regulations and fuel supply into account. With the version without a catalytic converter, exemplary emissions could also be achieved.
Another key word for the development of the 944 Turbo was: transaxle. This concept enables an unusual degree of driving safety and comfort through balanced weight ratios, low-vibration suspension of the engine and transmission and a large amount of space for passengers and luggage.

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The new transaxle alternative: the 944 Turbo in the Porsche range

The new 944 Turbo ranks between the 944 and the 928 S in the Porsche transaxle series. The price is on par with the Carrera, but does not compete with the classic rear-engine Porsche. It appeals to drivers who, beyond the economy and driving culture of the 944, want even higher performance and increased operating and driving comfort. At the same time, an environmentally friendly engine concept is implemented in the 944 Turbo that is tailored to the legal requirements and the environmental trends of the 80s.

In the Porsche range, the 944 Turbo occupies a central position between the 944, which is economical to buy and operate, and the 928 S, which belongs to the luxury category. The Porsche transaxle sports cars with their balanced concept have secured a growing market share in the area of exclusive sports vehicles. Although sedans predominate in the price range of over DM 40,000, a development in favor of coupés and real sports cars can be seen, which was largely influenced by the 944 and 928 S. With the 944 Turbo there is a new, performance-oriented alternative in this important area.

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Turbo technology and catalytic converter concept: environmentally friendly engine technology in sports cars

No other automotive company in the world has such extensive and extensive experience with exhaust gas turbocharging in racing and series engines as Porsche. With the 911 Turbo from 1974, the first and to this day most successful turbo road sports car came onto the market early on. It became famous not only for its high performance, but also for the comfortable and refined performance of the turbo engine.

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The proof thus provided that turbo technology does not have to be limited to racing, led to constant further development and refinement. This resulted in the development of a turbo version for the engine of the new 944 as well. The racing version was successfully tested in Le Mans in 1981. For the US market - a domain of the 944 - a catalytic converter version was included in the development at an early stage. This made it possible to take into account the emerging trend in Europe towards adopting the US emissions standards. One development goal was to achieve the same performance values with the catalytic converter version as without a catalytic converter.

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The smooth-running four-cylinder engine with balancer shafts, thanks to its modern design and the shape of the combustion chamber based on the latest research, offers ideal prerequisites for boosting performance through turbo-charging as well as for achieving low-emission exhaust gases. The normal 944 is - even without a catalytic converter - one of the world's best vehicles in terms of emissions. The lead was also maintained with the 944 Turbo. The mastery of the combustion process is one of the most important prerequisites for good exhaust gas quality as well as for the performance characteristics of the turbo engine basic compression. The relatively high load is already available in the lower speed range, in which the turbocharger is only in the filling of the cylinder increases slightly. With increasing engine speed and increasing supercharging, this compression requires operation close to the knock limit. However, a knock sensor prevents this critical limit from being reached or exceeded when using fuel with an octane number that is too low. The engine therefore works constantly in the range of the most favorable thermal efficiency, which has a positive effect on performance, consumption and exhaust gas composition in the same way. As with the naturally aspirated engine, the smallest possible manufacturing tolerances also contribute to this, which result in a very narrow scatter band of compression in the series engines. This enables extremely precise setting values for the ignition point and the fuel injection quantity. As with the naturally aspirated engine, the combustion is optimized by integrated ignition and injection electronics with non-contact and wear-free sensors (Bosch Motronic). The map with 256 support points stored in the programmable read-only memory of the Motronic is designed for the special conditions of the turbo engine.

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The exact adherence to the most favorable temperatures plays an important role for optimal efficiency. The 944 Turbo was given a water-cooled turbocharger that worked under operating conditions with low operating heat. A charge air cooler (intercooler) ensures a low temperature of the sucked in and compressed air. This creates favorable volumetric and thermal conditions in the combustion chamber, which has a positive effect on performance and the formation of pollutants (low proportion of nitrogen oxides). An external engine oil cooler also keeps the operating temperature in the optimum range on the engine side. The engine can be operated with 96 RON fuel in unleaded or leaded quality, in the version with a three-way catalytic converter, of course, only with unleaded fuel. With a tank capacity of 80 liters, the 944 Turbo reaches a range of at least 500 km, so that, with appropriate planning, refueling problems on trips abroad can be avoided.

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Sports car in the 80s: aerodynamics, comfort technology and balanced space concept

The high performance characterizes the 944 Turbo as a sovereign sports car. His driver can rightly count himself to the small group of those for whom speed, acceleration and use of power when overtaking or on the mountain are not a question of the technical possibilities. This is documented by the top speed of 245 km/h as well as the acceleration from 0 to 100 km/h in 6.3 seconds.

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The external look is supporting these technical capabilities and it's not just for show-off. One of the characteristics of the 944 Turbo is an understatement that is only possible through the existence of optimal engine and chassis technology. Because everything is there, nothing has to be faked and nothing has to be worn. Last but not least, this is expressed in the functional, almost inconspicuous smooth surface of the body.

This body with its excellent aerodynamic properties emphasizes the relationship to the 944, but has been differentiated and refined in many points: for example in the new front section with integrated light units, in the flush windshield, the side sill panels and the comformal  rear apron incorporated into the overall shape.

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The aerodynamic advantages of the body have been expanded: low air resistance thanks to a favorable Cw value (0.33) and small cross-section area (1.89 m2), low lift values thanks to the front and rear spoilers optimized in the wind tunnel and the rear apron that acts as an underfloor spoiler. The fact that the 944 Turbo is one of the most aerodynamically efficient vehicles on the world market is proven by the low consumption values at high continuous speed. Not least in these qualities shows the functional superiority of the sports car over the sedan with its necessarily larger cross-sectional area.

One of the values that cannot be seen at first glance is the sophisticated comfort technology of the 944 Turbo. The interior styling was done in the Weissach studio in close connection with ergonomic, orthopedic and air conditioning examinations. The seat position, seat system, dashboard and instruments arrangement, heating, ventilation and air conditioning have primarily been functionally optimized and given a uniform design. The driver's seat has separate electrical height adjustment front and rear, so that it can be adjusted to the body size in any position. Our standard equipment also includes the power steering with a leather steering wheel, the four-speaker system with an active window antenna, the electric window lifters, the automatic regulation of the interior temperature and heated windscreen washer nozzles.

The rear emergency seats have also been designed to be ergonomic; although they only offer limited seating space for adult passengers, they are comfortable and safe child seats that are also suitable for long journeys. They are part of the variable room concept with which the 944 Turbo can be adapted to many different transport tasks. As a 2/2-seater, it can also be used by four adults for a short time (those sitting in front then have to forego leg space), and its large luggage compartment enables all kinds of goods to be stored, which can be hidden from outside through the standard blind. It is easily accessible through the tailgate - loading and unloading is no effort. With the backrests folded down, the 944 Turbo turns into a two-seater with a large loading area, or sports equipment such as bicycles and inflatable boats can be stowed away. The generous front seating, driving comfort and driving characteristics remain unaffected by full use of the loading capacity.

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Predestined for safety, comfort and driving performance: the transaxle concept of the 944 Turbo

The versatile space available is one of the advantages of the front-engine transaxle concept, which at Porsche is on par with the rear-wheel drive concept and, in the future, the all-wheel drive concept of the 911 series . Compared to the rear engine and the mid-engine, the front engine enables better space utilization in the rear part of the car. The arrangement of the gearbox on the rear axle avoids excessive weight at the front. The result is an even distribution of weight which changes only insignificantly, even when the car is occupied and loaded. In addition to safe straight-line stability and neutral cornering behavior, this also ensures good traction of the rear drive wheels: the driver of the 944 Turbo can easily bring the high engine power onto the road.

Another advantage of the transaxle concept is the low-vibration and low-noise power transmission from the engine to the rear axle: connected by the transaxle tube with an internal "fast" drive shaft, the engine, gearbox and final drive form a unit that is connected to suspension points on the body. The motor is via resonance-free aluminum support arms and is hydraulically damped via rubber-metal bearings which are fixed in such a way to cancel that disruptive engine vibrations or resonances to uneven road surfaces. This is part of the reasons for fatigue-free driving in the 944 Turbo even on long journeys - corresponding to a six-cylinder there is a four-cylinder engine (compensation of the smooth running 2nd order inertial forces) and the elaborate noise insulation of the interior.

As in every Porsche sports car, a high-quality braking system is installed in the 944 Turbo. Four-piston disc brakes at the front and rear enable the transfer of high braking forces. Due to the balanced weight distribution, the rear axle can also be involved in the braking work to a large extent, with overbraking being prevented by a brake force regulator. The front brakes received ram air cooling.

Effective stabilizers (front 22 mm, rear 18 mm) and a tight damper setting characterize the sporty overall pressure of the 944 Turbo chassis. The standard low-profile tires in sizes 205/55 VR 16 at the front and 225/50 VR 16 at the rear are mounted on aluminum rims with perforated discs, the styling of which shows an affinity for the 928 S, not without purpose.

In spite of all the differences between the 944 Turbo and the 928 S, the Carrera and the 911 Turbo, it can be certified in one respect that there is complete agreement: the optimal quality, which is ensured by the best materials and exemplary work. With high reliability and a long service life, like every Porsche, it is a worthwhile investment for its owner and, thanks to environmentally friendly technology, a future-proof investment.

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