PORSCHE PRESS KIT
1977 - Porsche 928
The new, grand touring car from Porsche
Porsche presents its new, spacious sports car: the
type 928. High-grade engineering, a know-how put to
the test in racing and uncompromising quality mark this
new model and serves to satisfy the most demanding
The sports car in the service of individual mobility
The functional alternative
With the type 928, the Company of Porsche is strengthening
its leading position on the world's sports
car markets. Being an upward extension of the program,
the 928 will be in a higher price bracket than the
911-models. Like any other Porsche, it meets all the
demands of every-day driving as to functionality and
value in use.
The 4.5 liter, a-cylinder V-engine made of light metal
puts out 240 bhp. It is mounted in front and connected
with the rear mounted transmission-drive-unit by
a transaxle tube. This system which is also applied to
the Porsche 924, allows for an equal distribution of
weight - 50 per cent in the front and in the rear - as well
as great traction for the rear wheel drive. The quiet
engine features a powerful torque, giving superior
performance: it accelerates the 928 from 0 to 100 km/h
(0-62,5 mph) in less than seven seconds and gives
a top speed in excess of 230 km/h (143 mph).
The completely new chassis design offers a maximum
degree of safety and ride comfort. The rear axle features
an automatic toe-in control which ensures optimum
stability when cornering. This design has been patented
by Porsche and is known as the Weissach-Axle.
The 928 is fitted optionally either with a 5-speed gearbox
or a fully automatic transmission. The light, precise
steering is power-assisted but the degree of
assistance is dependent on the cars speed.
The roomy 2+2-seater coupe was designed to offer
maximum cruising and handling comfort. Functionality
and safety determined the shape of the car. The
standard equipment includes numerous novel details
such as an automatic central warning system and a
cleaning agent metering pump for the windscreen
washer system. The individual adjustability of both
controls and instrument panel allows for a "tailor-made
driving position." Customer wishes as to additional
features and appointments can be met to a large
degree. The shock absorbing Polyurethane covering of
the integral bumpers, as well as the extremely strong
roof are the result of Porsche research work in the
field of safety.
The robust, unitized body structure made of steel is
wholly galvanized - and carries a 6-year Porsche
warranty. Numerous aluminium components of body
and chassis as well as the long-life engine ensures a high
degree of value stability of the Porsche 928. Minimum
service requirements and a world-wide service
network - even considering the exclusiveness of
the car - ensures trouble free and low running costs.
In this respect, the 928 is in no way different from the
924 and the 911 range of models.
Porsche's decision to build a new, big sports car was made during the energy crisis.
Naturally, those responsible asked the question of the future of the sports car.
They arrived at a positive conclusion.
If the sports car were only an object of luxury, dependant on a small, well-to-do group of
buyers, the decision might have been different. However, Porsche has always
been regarding the sports car as an automobile with above average characteristics that
sets up standards not only in the area of performance, but also in that of safety,
comfort and long-life economy.
Thus. the high quality sports car continues to be the natural alternative to the sedan. One
of the qualities of the sedan is its comprehensive reserve of space. The sports
car, on the other hand, offers functionality. It is tailored to the driver who is offered an
optimum of direct association with the car, and an optimum of handling comfort.
A distinctly functional sports car is not an object of luxury, but an economical means of
transport. Wherever work and business require mobility and wherever high
demands are made of the vehicle, the sports car is the functional solution. Its use in
business requires a maximum of reliability and, of the sports car producer, a similarly high
standard of development, manufacturing and quality control, just as is the case
with comparable, high quality sedans.
In this respect, Porsche makes the highest demands of itself. For Porsche the sports car
is not a by-product, but constitutes the focal point of all deliberations. Every
component of the 928 is specially tailored to the particular characteristics of a sports car.
Also safety research and the time consuming and costly labor to observe international
engineering regulations are, in the case of Porsche, concentrated on the construction of
Such exclusiveness of engineering, combined with the acknowledged high standard and
efficiency of the service organization gives the 928 an absolutely special position
among the sports cars of the upper price bracket. It is the result of decades of development
work through which Porsche emerged to become the world's leading
producer of sports cars.
The concept of the 928
Challenge for the engineers
The task of building a big sports car for the 1980ies was a challenge for Porsche engineers.
The sports car, more than any other vehicle, is in the focus of public attention and
of expert interest. But it is also, like any other car, a factor of environment subject to
changing social standards and regulations.
Such abundance of differing points of view required the courage to seek and find new
solutions. So, it made no sense for this new car to feature a rear mounted engine, for most
of the engineering regulations are oriented towards the conventional car and
put the vehicle with rear mounted engine at disadvantage. On the other hand, it was out
of the question to abandon certain advantages of the sporty car with rear or
midship mounted engine - particularly the fine traction of the driven wheels.
The concept of the 928 is in line with the Porsche principle of not defending run-in dogma,
but of achieving the best possible result from given conditions. The decision in
favor of a transaxle system was made at an early stage after comparison tests had led to
favorable results. The same system was adopted for the type 924 which, though
marketed earlier than the 928, was developed only after the concept of the 928
was laid down.
Next to a favorable distribution of weight and a low center of gravity, the transaxle
system offers especially good prerequisites for a generous arrangement of
the seats in the best sprung area between the axles and for a foot room which is not
narrowed by the gearbox.
In spite of a deliberate limitation of the wheelbase and the overall length of the car,
the 928 was designed so as to offer room for four passengers. The big, variable
luggage compartment with rear hatch, too, emphasizes the versatility which is one of the
characteristics of a practical modern sports car.
Engine and drivetrain of the 928
Motioning for an a-cylinder engine
The driving comfort, an important component of the public roads sports car for Porsche
since the type 356, Is gaining significance. Therefore, the 928 could be fitted only
with an engine which combines high performance with a noiseless and vibrationless
operation as well as a great tractive power. These deliberations led to the choice
of the 4.5 liter, a-cylinder unit.
Eight-cylinder engines, already successfully employed in Porsche racing car construction.
have the technical advantage of an almost perfect balancing of the masses. The
distribution of the total displacement among eight cylinders makes sense in the case of
engines with displacements of more than three liters so the individual cylinders
do not grow too big. While, in the case of midship engine racing cars, the flat 180°
building principle offers certain advantages, front mounting offers ideal conditions through
the arrangement of two rows of cylinders at a V-angle of 90°: the engine has,
virtually, the length and the height of a 4-cylinder unit and is broader only in the upper
The compact shape of the engine led to the application of liquid cooling which, in
connection with the light metal construction, allows for extraordinarily favorable thermic
conditions as well as for good noise absorption and heating.
In designing racing cars, Porsche applies both liquid and air cooling and regards both
systems as offering interesting possibilities of development.
In order to keep the weight low in spite of the big volume of displacement, Porsche
decided to employ aluminum for both cylinder block and cylinder head. The
cylinder linings, too, are made of aluminum, their surfaces having been subjected to a
special treatment. That and the aluminum pistons the running surfaces of which
are covered by a thin layer of steel, combine for a maximum resistance to wear and a
minimum of friction.
Each cylinder head features an overhead, tooth-belt driven camshaft and hydraulically
operated valve pushrods which facilitate a low mechanical noise level of the engine.
A specially shaped oil pan and the easy-flow oil ducts cast in the cylinder block
guarantee a rich oil supply also under unfavorable conditions, such as quickly maneuvered
bends. The crankshaft is made of forged steel, the connecting rods are sintered.
The K-Jetronic fuel injection, introduced by Porsche several years ago and, in cooperation
with Bosch, perfected to ensure safe functioning, takes care of an absolutely even
fuel supply of the eight cylinders. With a compression ratio of 8.5 : 1 the engine
does well enough with regular fuel. The no-contact ignition system, self-adjusting valve
pushrods, the closed cooling circuit with viscose fan as well as oil change intervals
of 20,000 kilometers are attributes to the low maintenance needs of this modern
engine design with a safe future.
The engine has a two-discs clutch which was specifically developed for this car. Porsche
intensively dealt with the problem of attaining a comfortable clutch operation
when using a high torque engine and mechanical transmission and, at the same time, keep
the shifting power to a minimum. The two-discs clutch, while highly resistant to wear,
.offers a comfortable clutch operation which is unexcelled in this class of performance cars.
Engine and gearbox are combined into one unit by the transaxle system. In addition to
the favorable distribution of weights, this arrangement offers advantages in the
area of vibration problems: the long distance between the two bearings each front and
rear means a specially good protection from vibrations in the interior. The 5-speed
gearbox mounted in front of the rear axle - it features Porsche synchromesh - was
designed to be highly smooth and noiseless. It has a noiseless 5th speed which
transmits the power directly to the driven wheels without using cog-wheels. The short,
precisely operating shifting mechanism was fitted with a link which keeps gearbox
vibrations from being relayed to the shift stick. Twin universal joint shafts with drive length
compensation drive the rear wheels.
The optional automatic transmission meets the special requirements of sporty driving in
the Porsche 928 and is marked by quick reaction, extensive possibilities of influencing
it and, finally, by great efficiency.
The chassis of the 928
For optimal controllability
In the case of a sporty car with a high performance engine, it proved right not to restrict
the power applied by the driver to the accelerator and the steering wheel to two wheels.
The effects of propulsion and steering may be balanced against each other and an optimal
controllability of the car will be the result.
Therefore, Porsche, right from the start, had no doubts about retaining the rear wheel drive.
With the aid of the transaxle system, an optimal distribution of weight of about 50 : 50
could be accomplished, a ratio which changes only unessentially when the car is fully
loaded. The greatest concentrations of weight - the engine in front, gearbox and drive,
battery and fuel tank in the rear - are located at both ends of the car which aids the
directional stability desired for a car to run on public roads (high moment of inertia around
the vertical axis). The engine was moved up to the front only as far as required by the
layout of the interior. In spite of short overhangs, both the front and the rear sections
feature sufficient energy absorbing space in the interest of passive safety.
Already before World War II, Porsche was one of the pioneers of the independent wheel
suspension for road and racing cars. The low center of gravity of the 928 allowed for the
adoption of extensive knowledge gained from racing car engineering for the benefit of
readability and riding comfort.
The front wheel suspension by trailing arms featuring a negative scrub geometry makes the
steering insensitive to adverse influences of the road surface as they may occur when
braking on a slippery surface or in case of tire defects. With a view to the high sensitivity
when maneuvering bends, the elasticity of the steering system is metered most exactly.
Special attention was paid to a smooth keeping of a straight course as well as a proper
reaction to a quick succession of opposite movements of the steering wheel (change of
lanes). The servo effect is reduced as the speed increases, effortless maneuvering
combines with reliable road holding at high speeds. Extremely rigid twin-trailing arms, made
of cast aluminum, guarantee an absolutely correct control of the wheels and smooth
reaction to rough surfaces.
The rear axle of the 928 (Weissach-axle), with lower diagonal and upper transverse
trailing arms, compared with conventional types of individual wheel suspension offers a
marked gain in riding safety as, in exactly calculated fashion, it compensates for the
changes of toe-in occurring with and without forward propulsion. Particularly when
decelerating in curves may changes of the toe-in have disadvantageous effects as the car
tends to turn itself into the curve. Analyses of accidents have shown that the majority of
mishaps in curves end at the inner side of same. This leads to the conclusion that the curve
stability of the car was overstrained rather than the lateral support forces.
The toe-in control of the new Porsche rear axle is accomplished by a "steering" -element
mounted in the lower diagonal trailing arms. Referred to as a controlling swing,
its movements are exactly defined and limited. The undesired lessening of toe-in caused
by deceleration and as a result of the inevitable elasticity of the suspension is compensated
by this element. Ultimately, the rear wheels would not show a steering effect, but will
practically stay in position, with and without forward propulsion.
This effect is supplemented by certain anti-squat measures (in case of acceleration) and
anti-dive measures (in case of deceration). Driving thus becomes not only safer but also
easier on the driver's nerves as there are no disturbing factors he would have to correct.
The braking system of the 928 consists of four hydraulic, servo-assisted disc brakes with a
diagonal dual-circuit system and a mechanical emergency brake (drums) acting on the
rear wheels. The disc brakes are fitted with "floating-frame" braking pads. One important
advantage: The maximum temperature of the brake fluid is 90° centigrade which is far
below the boiling point. Thus, there will be no brake fading because of steam bubbles
developing. Material and assembly of the brake system piping are designed for long life
and offer maximum protection against failure.
The body of the 928
A design of stable value
To Porsche, the shape of the body is a functional element of the automobile.
None of the previous Porsche models showed any dependance on fashion trends.
Any deliberations of that kind did not play a role in the case of the 928 either.
The more care was applied instead to finding an equally optimal solution for the shape
and function, for the entire car as well as for each detail. A car like the Porsche 928
is to remain a common sight on the roads for many years and, as a commodity, it is to be
of stable value for its owner - both as far as the design and all the other qualities are
Extreme and "exciting" elements of styling will, therefore, be absent from the 928.
Smooth and slightly concave planes with rounded off edges dominate the outer skin of the
car. Designing the details was not only influenced by aerodynamics but also by
considerations of safety. The interior, in the sight of the driver, features subdued,
non-reflective surfaces to avoid any optical distraction. The rest of the interior is marked
by a friendly, comfortable atmosphere. There is a great choice of trim and cloth for
the customer to meet his personal ideas.
Porsche has always been leading in a functional arrangement of the cockpit and the
instruments. The dials, switches and levers of the 928 are arranged so that all functions
which are important during ride may be executed with rational, brief movements.
Individual levers and switches were not endowed with too many functions.
The possibilities of individual adaptation of the car to the driver go, in the case of the 928,
far beyond the usual: next to the seats which feature longitudinal and backrest
adjustability (option: electrical operation plus additional adjustability of height),
the steering wheel may be easily adjusted in height by loosening a lever.
The instrument carrier is adjusted simultaneously so that the good readability of the dials
is maintained in any position the steering wheel may have been put. For reasons of safety,
no provision was made for an axial adjustability of the steering wheel. However, pedals
and foot-rest may, just like the stick shift, be adjusted to suit the driver's measurements.
The door-armrests may be tilted to allow for a comfortable position when cruising.
In short, the 928 literally offers a tailor-made sitting position.
To further improve the riding safety, numerous provisions were made for the 928,
some of them being absolute first-timers. For instance, the windscreen washing system was
fitted with an additional metering pump with timing-relay, jetting a special cleaning agent
onto the windscreen so that visibility obstruction by silicone or oil may be removed during
ride_ The cleaning agent reservoir, about 0.6 liter, lasts a long t ime, and, similarly,
the container for the windscreen and headlamp washing fluid, having a capacity of 8 liter,
is amply dimensioned.
The two stage rear window heater is supplemented by a large wiper with parallel operation.
The wiper motor is mounted to the body rather than to the rear hatch and operates
the wiper via clutch which, when opening or closing the rear hatch, automatically turns the
operation off or on. A vacuum locking system automatically locks and unlocks the door on
the passenger side as the driver-side door is locked or unlocked. First aid kit, a warning
sign (triangle), tools and foldable spare-wheel (plus electric pump) are incorporated
into the car so they save space and are easily accessible.
A newly developed central warning system informs the driver automatically about
possible disturbances. In the event of such, a warning lamp mounted to the instrument
carrier lights up and cannot be ignored. The scale of the warning system located at the
center console indicates the source of the disturbance. The controlling functions
are divided into two main groups: in the case of vital disturbances (e.g. loss of engine oil
or braking fluid) the warning lamp blinks and cannot be shut off. When the lamp stays lit
this is an indication of refilling or replacing needs which need not be attended to
immediately (e.g. washing fluid, brake linings). In that case, the lamp may be shut off by
pressing a button. It will automatically turn on again when the ignition is shut off and then
turned on again.
The recessed headlamps, electrically moved into position, may be adjusted from the
driver's seat for correct lighting distance which may vary in accordance with different
loading conditions. When the lamps are recessed, their glasses are still free to be washed.
Two additional headlamps (high beam, flasher for daylight driving) and two fog lamps
front as well as two fog lamps in the rear are incorporated into the bumpers. The center of
the electrical system is easily accessible and mounted under the foot-room of the
passenger_ The standard equipment includes sun-visors for the rear seat passengers.
An electrically operated slide roof has two functions: it may be slid open or tilted up.
Especially developed for the 928, but also available for other Porsche models, is the
Porsche-cassette-radio which combines excellent reception characteristics with a clear
and comfortable operation. The automatic station tracer has two sensitivity stages.
Four loudspeakers guarantee a quality of sound which meets highest expectations.
Other standard equipment of the 928 includes: speed control by Tempostat.
The heating system employs a hot and cold air mixture and thus reacts quickly and exactly
to lever adjustments. Its effectiveness remains largely independent from the car's speed.
Of the five blower stages, the first is in permanent operation. The flap system is vacuum
controlled and allows for a great variety of adjustments of the temperature and the warm
and fresh air distribution. A highly efficient air condition unit is available for the 928 as an
option, the system including cooling of the glove box. The unit may also be built in later.
The screwed-on front wings, the hood and the doors are made of aluminum.
Extremely solid roof bars and an integrated roll-over bar guarantee maximum stiffness and
resistance of the passenger compartment. The angled steering column is crash-proof and
the steering wheel features an additional element of deformation. The deformable bumpers
made of polyurethane retain their shape in case of minor impacts and have a layer of
special, elastic paint. The unitized body consists of galvanized steel - which, like those of
all other models, is endowed with a 6-years Porsche warranty.
Driving the 928
Performance as safety factor
The sports car will always remain the most perfect form of individual transportation.
This fact is emphasized by the growing popularity of sports cars in the United States of
America, a country with a multitude of varying speed limits. It would be misunderstanding
the sports car to say that the only essential characteristics of such a car are performance
and speed. They are found with other cars, too, and it is only the combination of high
performance and optimal controllability that shows the true nature of the sports car.
It is only there where there is justification of the prestige with which the sports car is
For a sports car with such high standards as featured by the 928 it is natural to produce
top performance data. But this always has to be seen in connection with the performance,
as an essential factor of safe driving, being adaptable to the driving conditions .
The 240 hp (177 KW) of the 4.5 liter V-8-cylinder engine are put out at 5,250 rpm -
a relatively low figure, meaning a low noise level both in- and outside. The electrically
controlled maximum revolutions are 6,300 per minute. The maximum torque of 37 mkp
(365 Nm) is achieved at 3,600 rpm which demonstrates that the engine of the 928
develops full power already at medium revolutions.
Owing to the favorable distribution of weights, this power is easily and smoothly transferred
to the road so the 928 may develop its top performance without effort and with little
noise only. It accelerates from 0 to 100 km/h in 6.8 seconds. It takes 27 seconds for one
kilometer from standing start. The top speed is above 230 km/h.
The significance of these optimal data for everyday driving is to be found in the easiness
with which the specific, sensible driving performance may be realized in ordinary traffic.
The acceleration data demonstrate the available power reserves for brief passing
maneuvers without risk as well as the superior climbing abilities of the vehicle; the top
speed which, of course, is beyond normal speeds in regular traffic, shows that, depending
on varying traffic conditions, any speed may be realized at any time. The choice is the
responsibility of the driver - which is a matter of course and which is true for any car.
The technical layout of the vehicle enables the driver to dispose of speed and power
reserves safely and free from fatigue: both clutch and manual transmission and automatic
transmission allow for an effortless selection of speeds, the positions of the selector are
clearly defined. The steering needs no familiarization and relays a distinct "feeling of the
road" to the driver, the brakes combine reliable no-fading deceleration from high speeds
with easy metering in tight traffic.
The sophisticated chassis, too, is in the service of riding safety reserves - at high cruising
speeds as well as in maneuvering curves on both tractive or slippery roads.
Clearly signalized readability and good-natured attitude in extreme roadholding situations
give the driver distinct information about avoiding risks. This was also taken into
account in the choice of tires: the standard tires 225/50 VR 16 combine a safe high-speed
ability with easy cornering characteristics and good drainage of water. For winter
conditions, Porsche recommends narrow tires of the type 185/70 SR 15 M+S.
When designing the 928, Porsche was not only keen on developing a top class sports car.
A great number of technical features of this car demonstrate that genuine progress in
automotive engineering continues to be possible and necessary. They emphasize that only
an advanced development in all areas of automotive engineering, in the fields of active
and passive safety, just as much as in those of riding and handling comfort, can do justice
to the importance of the automobile as a means transport and communication.