They have always been exceptional automobiles: sports cars from the Porsche 928 range. With the 928 GTS a new peak in development was achieved in a line which began in 1977 with the first eight-cylinder Porsche. Since then the unmistakable silhouette of the 928 has become the symbol of a sovereign touring sports car, More than any other automobile, the 928 embodies the ideal of Grand Touring. On Germany's autobahns you see the 928 in all its variations far more often than its registration numbers might suggest. It is one of those cars which record the highest annual mileage figures.

Already rated one of the finest cars in the world many years ago by Formula 1 Worid Champion Jackie Stewart, the 928 has not merely retained its special position in technology, performance and comfort. Thanks to constant innovation, this has been systematically extended. The basic design and countless updates introduced since 1977 have pointed the way: the safety structure of the body, high aluminum share of the engine, body and chassis, energy-absorbing nose and tail, the track-correcting Weissach rear axle.

The sovereign performance level of the current 928 GTS is indicated by maximum torque of 500 newtons, resulting from a displacement of 5.4 liters. Torque values as well as engine output of 257 kW/350 HP hold true for both transmission alternatives, automatic and manual gearbox.

Engine and performance characteristics

The 928, conceived as a sports car, differs in important features from other coupés of its price and performance class. The precise suspension and direct servo steering without lag provide safe driving reserves which can be fully exploited on the road as well as the track. The same is true for the engine. The completely-aluminum power plant can't deny its relationship to eight-cylinder racing engines from Porsche, not even in this 5.4 liter version. Two overhead camshafts for each of the cylinder banks, set at an angle of 90 degrees, four valves per cylinder arranged in a vee above the combustion chamber, low inertia weight and resonance charging of pulsating gas columns with their ramjet effect once used on unblown racing engines, give the 928 engine a spontaneity and rev potential only found in engines with a sporting heritage.

A clear excess of torque

Rev potential reaching to 7000 RPM, with output values above 300 HP as low as 4000 RPM are typical figures for a sporting, high-performance engine. The torque curve pattern, on the other hand, indicates that this Porsche V8 can simultaneously offer the qualities of a comfort engine of the upper class. Here too, the competition falls behind. The dream value of 500 newtons is reached at only 4250 RPM, while torque remains above 400 newtons in the range between 1000 and 6000 RPM, In all situations where high-performance is not required this means comfortably gentle driving at low revs in the upper gears of either manual gearbox or automatic, while unusual acceleration and mountain-climbing potential is avalilable, even without shifting down.

Ideal mass balance of an eight-cylinder engine is evident in vibration-free ope- ration over the entire revolution range, despite firm engine mounts. Optimum use of fuel energy through engine-map ignition with electronic knock control and high volumetric effiency of the cylinders through two-stage resonance filling, cause combustion audibility. Silent engine operation was not a feature of the project book although all frequencies and sound levels which might result in reduced long-distance comfort, were avoided through acoustic optimizing. The result is unusual running and sound comfort by sports car standards. In conjunction with stiff springs which absorb vertical vibrations, there is a sporting overall comfort picture favorable for passenger well-being on short or long trips.

Performance weight of the 928 GTS

At less than 4.7 kg/HP this reaches into racing realms. The acceleration potential this makes possible lies beyond the standards of road traffic. The fact that power reserves can't or needn't even be fully utilized in any normal situation forms the background to sovereign driving in the 928 GTS. Expressed in figures this means less than six seconds from O to 100 km/h and around 25 seconds for the kilometer with standing start. A top speed of 275 km/h indicates the ease of acceleration available, even in the realm above 200 km/h.

Autobahn consumption values (EC standard) of 9.8 liters/100 km at 90 km/h and 12.0 liters at 120 km/h are realistic. Values for the EC city cycle of 20.7 liter/100 km with manual gearbox, 18.8 liters with automatic, are higher than normal use, due to a measurement method which demands full acceleration in the lower gears. Effect, durability and high-speed reliability of the catalytic converter system (two three-way converters) are outstanding for the upper performance class.

Drive and chassis

Safe delivery of the high propulsive power by a 928 GTS is based on advantages of the transaxle building style. The front engine and gearbox at the rear axle - manual or automatic - are rigidly joined by the transaxle tube. As an integral unit, this drive system provides vibration-free power transmission balanced weight distribution and favorable loading of the drive wheels under all load conditions.

"Dynamic kick-downs" in the automatic version is new for the 1994 model year. This electronic shift system effects downshifting of the transmission, not only when the throttle pedal is pressed to the floor, but even during rapid throttle pedal movements. At the same time, rapid pedal movements also cause delayed upshifts. The dynamic kick-downa shift program meets the desire for brisker acceleration with more comfort than classic kick-down shifting, alt- hough this too remains available for the 928 GTS.

Superiority through traction

In order to transmit high torque, even with unfavorable surface con- ditions, the 928 GTS is fitted in production with the Porsche limited-slip differential (PSD). This electronically-controlled, variable, transverse lockup uses the ABS signal and automatically prevents spinning of a single wheel. Front wheel control is handled by extremely stiff dual wishbones in aluminum. Rear wheels are controlled by a lower diagonal arm and upper transverse arm so that bump toe-in occurring under the influence of high lateral forces is automatically corrected. This kinematics, known by the name of "Weissach axle", is one reason for the safe, unproblematic handling of a 928 GTS, even at extremely high cornering speeds. During a comparison drive under racing conditons on the North Course of Nürburgring this chassis proved its superiority to renowned rival vehicles with fastest lap times.

Like chassis qualities, the high performance potential of the brakes is not only up to race-level lap times but equally beneficial to driving safety in road traffic. Aluminum, four-piston, fixed-saddle brakes with vented discs for all wheels and carefully-defined, cool-air routing, based on years of racing experience, are equal counterparts to high engine output. They produce top values in decele ration and braking distance. Variations in surface conditions are reliably ironed out by the ant-block system (ABS) so that uneven effects, even under ful braking, and tire damage cannot occur.

A new design of 17 inch wheel for the 928 GTS provides optimum prerequisi tes for brake cooling, thanks to open construction, Dimensions (7,5 J x 17 in front, 9 J x 17 in the rear) are carefully attuned to the tires: 225/45 ZR 17 in front, 255/40 ZR 17 in the rear.

Safety - outstanding realization

A key prerequisite for driving safety, even at highest speeds and over uneven surfaces, is a torsionally resistant vehicle structure. Load-bearing parts of the bodywork are made of steel, hot-dipped galvanized on both sides the safety passenger cell is additionally protected on the sides by sturdy steel beams in the doors. Deformable front and rear sections of plastic are insensitive to smaller bumps, the invisibly integrated, light-alloy bumpers on impact tubes absorb energy in a collision. Weight reduction through aluminum parts (such as front fenders, engine lid and doors) and lift reduction from a rear spoi ler of polyurethane (car color or black) belong to the proven 928 range features stemming from Porsche race technology. Classic fold-out headlights and new, more streamlined outside mirrors contribute to the low air resistance of this 928 GTS (Cd_d u 0.35).

Air bags for driver and front passenger, which Porsche was the first German automobile manufacturer to introduce as standard, are an additional plus for passengers in the 928 GTS. They form a further component in the overall system of active and passive safety which has brought the 928 GTS a leading position worldwide.

Comfort and fittings

As a sports car for long-distance drivers the 928 has been equipped with complete, well-thought-through, fittings from the first. Functionality as well as active and passive safety came before luxury here. The high-pressure head- light washer unit, for instance, made its debut in the 928 - a safety detail like the diagnostic system introduced for the 928 and now a reliable reporter on refilling needs of coolant or brake fluid for instance. Steering wheel adjustment with an instrument pod which moves as well, central locking, headlight range control, integrated anti-theft protection - all these have long been self- evident for the 928 driver, The audio unit also meets top demands whether as the Blaupunkt Bremen cassette radio or Porsche London CD radio also fitted with automatic RDS traffic-advisory system and Key Card protection.

Endurance racing experience benefited the lighting at an early stage. Large H4 headlights plus H3 auxillary lights and H3 fog lights retain their leading position, regardless of fashionable novelties. Automatic regulation of the air conditioner which saves the driver adjusting to heat or cold has also become a model for others.

Digital mechanic as constant companion

The diagnostic system in conjunction with an on-board computer has been developed to become an information system with three priorities which embraces a large number of warning functions. Depending on country-specific equipment, the text appears in various languages with later switch from one language to another possible. Certain warnings are stored in electronic chips so eventual faults can be called up later by a workshop. Priority I includes faults which require immediate correction, such as engine temperature above 120 degrees, low oil pressure or lack of brake fluid. These faults are shown in red with blinking symbols. Priority II, shown in red with steady light, includes too little cog-belt tension and low coolant or engine oil levels. Priority III indicates it is time to renew brake pads or bulbs and suggests topping up the water container of your windshield washer unit.

The on-board computer provides clear information on a large, easily-read display - for instance, remaining range (computed on the basis of previous consumption), or average speed. Calling up such information sequentially doesn't distract the driver. Alongside the odometer which cannot be canceled, there are two trip odometers which can be activated and even an easily-operated stopwatch.

Seating and spatial comfort

The 928 set standards for seating comfort levels of driver and passenger. Individual electric adjustment of the driver seat over a wide range comes with three standard memory options which include adjustment of the rearview mirror.

Folding rear seats in the 928 are a fixed part of the typical Porsche "2+2" concept. They don't replace a four-seater but offer outstanding comfort for those of up to middle size, even over longer distances. The 928 GTS is suitable for children, even on long-distance trips. When one or both rear seats are occupied the large rear luggage area still offers sufficient load capacity - this 928 GTS provides unusual range in its variations of seating and load potential by sports car standards. Loads are prevented from sliding about by the luggage net, an elastic trunk blind protects them from casual eyes or direct sun. Transport capacity is another indication of what this long-distance sports car offers like no other: Grand Touring