THE PORSCHE 924 - A DIFFERENT DIRECTION
By Dean Lewellen
reprinted from Going Places, official newsletter of the Arizona Region PCA
It has been said that the first production Porsche, the Model 356, grew
out of the bold inspiration and enthusiasm for sports cars by Ferry
Porsche, aided by the design studies based on prewar and postwar
Volkwagens by Erwin Komenda and Karl Rabe. The Model 356, first produced
in 1948, was a groundbreaking, pathfinder design concept which is as
timeless today, as seen in the current Model 996, as it was fifty-four
years ago in Gmund, Austria. When the Model 924 arrived on the European
motoring public scene in early 1976 and in the United States in June of
1976, it was clear that a new and radically different direction had been
taken by the Porsche design staff in Zuffenhausen, Germany. The Model 924
grew out of perspiration instead of inspiration and was an austere, sales
and marketing department driven design solution utilizing Volkswagen and
Audi components instead of tapping the enthusiasm for and dedication to
the pure performance sports car niche Porsche had worked so hard to create
during the Company's first thirty years.
To be more fair to the business side of Porsche, the marketing reports
defined the need for a less costly, entry level Porsche which would
capture more market share than the Model 914 had been able to establish.
The VW-Porsche business agreement that fostered the Model 914 was still in
force and the Porsche and VW employees who staffed the VW-Porsche
Vertriebsgesellschaft (VG) would be the catalyst group to define the
requirements, approve the designs and manage the production, sales and
marketing of the Model 924, which had the internal project/contract number
of EA425. Erich Filius of Porsche and Klaus Schneider of VW jointly headed
the VG and were responsible for establishment of the basic parameters of
the new car--more interior space, maximum use possible of low-cost,
high-volume VW based components, and, a design that unified with other
Porsche product offerings. The unified design meant that the new car was
to have technical similarities with and family resemblance to the more
expensive, purely Porsche sports car being developed to replace the Model
911. This was the early 1970s, folks, and the replacement car we are
talking about was the Model 928 which arrived in 1978. It never did
replace the Model 911 as the top flagship of the Porsche fleet and 928
production ceased in 1995, but that's another story.
As the design solidified around the two main drivers--use of VW based
components and unification with the 928-to-be configuration--several
design options fell by the wayside. No front wheel drive layout like the
Audi 100 or VW Rabbit, no rear/mid engine layout like the 911 or 914, the
Porsche people would not agree to a live rear axle design, and, only
water-cooled engines met the unification criteria. The engine choice was
slam-dunked by the low-cost, high-volume requirement and was the VW built
EA831 engine used in the Audi 100, VW LT van, and later in the American
Motors Gremlin--no kidding! The transmission/clutch location went through
all three possible combinations for placement with the result being a rear
mounted transaxle gearbox with the clutch assembly mounted in the
traditional location in the flywheel bellhousing. This arrangement
provided for a large polar moment of inertia for the car about its lateral
axis, which is what makes the 924-944-968 configurations so incredibly
stable in corners. The location of the transmission at the rear meant that
the drive shaft mounting, support and control was very important since the
drive shaft turned at engine speed instead of gearbox output shaft speed.
Many hours of trials and testing was done on a BMW 2002 "test
mule" equipped with an Audi engine (front) and transmission (rear)
trying out several candidates for the drive shaft design of choice. The
final design was a hollow shaft (read torque tube) mounted solidly between
the bell housings on the back of the engine and the front of the
transaxle. The actual drive shaft, 20 mm in diameter and sixty-seven
inches long, was mounted inside this tube on four ball bearing supports
mounted in concentric rubber rings on the shaft and tube. Splined
connections mated the drive shaft to the clutch and the transaxle at each
end.
Suspension components were also found in VW and Audi factory parts bins.
The rear trailing arm suspension was lifted directly from the VW Super
Beetle. The half shafts connecting the transaxle drive to the rear wheels
were from the VW Type 181 utility vehicle known in the United States as
"The Thing". The front MacPherson strut suspension was cobbled
from Super Beetle front coil struts linked to Rabbit/Scirocco lower
wishbones. The rack and pinion steering gear from the Rabbit/Scirocco was
employed with a slight modification in the steering ratio and kinks added
to the steering column for crash protection. VW front shocks and Boge rear
shocks were also specified. Optional Porsche designed anti-roll bars were
a rare 924 unique suspension feature. The braking system selected was from
the VW K70 sedan and was a front disc/rear drum setup which was a ten year
step backward in time for a Porsche braking system. The EA425 (924) was
fitted with fourteen-inch, stamped steel wheels with a rim width of 5 1/2
inches. Truly this was parts bin engineering at its best, if you were a
marketer, or, at its worst, if you were an engineer.
A member of the Porsche styling team, Harm Lagaay, is credited with the
overall styling theme of the 924. The hidden headlights, inclined engine
and tradition of no grill gave the car the popular wedge shape rising to
the large rear window/hatch at the rear. As with the mechanical
components, the body and interior parts were selected from existing VW
stock wherever possible--Golf/Rabbit heating and ventilation system and
door latches from the Scirocco. The Lagaay team was able to provide an
interior of Porsche design origin. Some unique features were the three
large main instrument dials in front of the driver which housed the
speedometer in the center, very un-Porsche-like, a fuel and water
temperature gauge on the left, and, the tachometer on the right which had
the red line portion of the tach in the upper quadrant of the gauge. Some
early and on-going controversy has existed over the steering wheel shape
which is somewhat eccentric when centered to provide more clearance with
the driver's legs. The problem comes when the wheel is turned ninety
degrees or more during cornering in that this nice clearance becomes real
interference between steering wheel, hand and legs of the unsuspecting
driver.
History of the EA425/924 project contains a story about the dark days of
the project which began in the fall of 1973 when the VG agreement between
Porsche and Volkswagen was mutually dissolved. Since Volkswagen had put up
most of the $50 million spent on development up to that point, they
claimed the rights to the yet unborn sports car as a Volkswagen future
product, much to the chagrin and disappointment of the Porsche now
ex-partners. Well, the oil crisis of 1974 took a bitter toll on VW's
vision of the future and the waves of red ink swirling on their balance
sheets swept most of the VW management team from their seats on the
sinking ship. Porsche properly procrastinated and in early 1975, the new
Managing Director of VW met with Porsche leadership and reached an accord
which would see the 924 built in a VW factory in Neckarsulm, which was on
the block for closure and was located twenty-seven miles north of
Stuttgart. It was a win-win solution. Porsche would own the design, the
tooling built so far and be the responsible manufacturer of the Model 924.
Volkswagen employees would build the car, order and/or supply the parts,
keeping their jobs after all.
The Model 924 was first offered for sale in the USA in July of 1976 as a
1977 model at a base price of $9395. The Audi four-cylinder engine was
rated at 95 SAE HP @ 5500 rpm. This engine produced 110 HP in European
tune. The four-speed manual transaxle provided for an overall weight
distribution of 48-52 per cent front to rear which made for well balanced
handling. A five-speed gearbox was made available in 1979 and a
turbocharged engine producing 143 HP was offered in 1980. Things were
really getting better fast, making getting fast better. A special
"Turbo" Sports Package was offered which included 16"
wheels, heavy duty stabilizer bars and shocks all around, and, vented
four-wheel disc brakes--now we're talking Porsche!
Production of the original Model 924 ceased in 1982 as the ten years of
knowledge and experience gained allowed for a controlled evolution to the
Model 944 series of water-cooled Porsches. However in 1987, the Model 924
was reintroduced as the "924S" which was really a 924 body and
chassis with the 944 engine and running gear. These cars are rare and
special making excellent candidates for the "944 Spec" class in
local Valley of the Sun racing venues.
As with the Model 914 program, the Model 924 project provided many
priceless experiences and lessons learned about joint-venture partnerships
for the people of Porsche. They also got to put into practice the
knowledge and capabilities they had acquired through contracted
development work with and for other vehicle manufacturers by designing,
building and testing their very own automobile powered by a water-cooled
engine. The Model 924 today is a fast fading icon of the Porsche marque,
but its technology lives on and improves in the evolutionary lineage of
models such as the 944 and 968 editions of these water-cooled wonders.
References:
Ludvigson, Karl, Porsche Excellence Was Expected, 1977
James, Drayton, Editor, The Porsche Family Tree, Published by PCA, 1995
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