Probably the most unusual prototype Porsche you’ll ever see
Unlike other car makers, Porsche has seldom bedecked its motor-show stands with concept cars, new designs intended either to solicit public opinion or to foreshadow future products. There are a few exceptions, such as the first 911 Turbo and of course the Boxster concept of 1993, which turned out to be a starting point for a new kind of Porsche. Iʼve always felt that the poor reception given the controversial Panamericana concept of 1989 may well have discouraged Porsche from putting its ideas for future models in front of the public.
Three years before the Panamericana, another concept Porsche took to the road. It wasnʼt publicly revealed, however. Instead the matteblack coupe was hammered around the test tracks of Weissach, occasionally snapped by an opportunistic photographer. What could it be? editors speculated. Was it a completely new model? A possible 911 replacement? It looked the part with its plunging nose and big tailmounted wing.
In 1987 Porsche came clean. Built by the Weissach engineers as Project 2696, the car was their new tool for exploring advanced concepts of handling and suspension. ʻItʼs ugly as sin,ʼ said Peter Schutz, Porsche chief at the time. ʻIt looks like a camel or something, instead of a horse, because we pay very little attention to its appearance.ʼ This was the Type 2696, also known as the PEP — standing for Porsche Experimental Prototype.
ʻItʼs a rolling test stand,ʼ explained Schutz. ʻIt is a car with which we can do some preliminary feasibility evaluations of concepts. It gives us the opportunity to evaluate different drive systems, because it is literally a Tinkertoy.ʼ This was a reference to a kidsʼ construction set invented in Chicago in 1914. I well remember making interesting structures of various kinds with my Tinkertoy sticks and circular hubs.
ʻThe idea was to create an adjustable car,ʼ said engineer Helmut Flegl, whose research department built the PEP. ʻAt one stage it looked like a 944 with a different rear end and sounded like a 911.ʼ Its core was an aluminium monocoque center section, which extended from the front toeboard back to the area behind the two seats. In the rear of the monocoque were a 5.3-gallon rubber fuel cell — it wasnʼt expected to go far from Weissach — and a 3.2-gallon oil reservoir.
Fronting the greenhouse was a 944 windscreen. The 944 also provided the roof and B-pillars. Doors were adapted from the 944 but fabricated in glassfibre, which was used for the entire exterior skin. The steering column with its attached instruments was borrowed from a 928.
Bolted at front and rear to the PEPʼS central monocoque were welded-steel tubular structures. Carried by these were the suspension systems that Porsche wanted to try out with the PEP. The attachments were made in such a way that the torsional stiffness of the complete vehicle could be varied to try the effects of different structures on handling behaviour.
Suspension at the rear was laid out as trailing arms which were sprung by high-mounted coils. High coils were used at the front as well, acting against the upper arms of a parallelwishbone setup. This gave the design freedom that was needed to allow all four wheels to be driven. The tubular structures also gave the flexibility needed to try completely different suspensions.
Changes in the PEPʼS weight distribution and polar moment of inertia could be tried by bolting weights to the tubular frames. ʻYou could make changes fast,ʼ said Volker Berkefeld, who worked with the PEP, ʻand move masses
“WHAT COULD IT BE? WAS IT A POSSIBLE 911 REPLACEMENT?”
around very well.ʼ Wheelbase length could be changed as well. To accommodate this the drive shaft from rear to front, and its surrounding tube, were telescopic.
The PEPʼS basic drivetrain powered all four wheels with its 911 engine mounted in the rear. To reduce mass overhang at the rear, however, the flat-six was to be mounted above the transaxle, driving it through a train of gears. The drive train was laid out so that the PEP could be front-driven, or rear-driven, or four-wheel-drive with different front/rear torque balances. The purpose of the wing at the rear of its snubnosed bodywork was to permit the carʼs aerodynamics to be balanced to resemble that of production models.
Porsche made bold claims for its Type 2696. ʻIn the future it will no longer be necessary to build costly prototypes or heavily modified production cars in the concept phase of a newly-developed vehicle,ʼ it stated. ʻIn advance its handling can already be evaluated and optimised with the Porsche Experimental Prototype.ʼ
The reality was less rosy. ʻIt was too crude,ʼ said Flegl. ʻIt felt very much like a prototype. You couldnʼt get the feeling of a real car. To decide whether a concept was good or not was impossible.ʼ Volker Berkefeld seconded this negative assessment of the PEP. ʻIts acoustics, vibration and so forth made it not representative of a real car. The idea was good, but itʼs better to build the components into an actual car. The driving feeling is then much better.
ʻWhen you try to present a new idea internally,ʼ added Berkefeld, ʻitʼs best to present it in a very good form — not too noisy, for example. Otherwise people donʼt like it!ʼ He added that later developments leapfrogged the PEP idea in any case: ʻBasic suspension issues can now be resolved with computers.ʼ Engineering chief Horst Marchart confirmed this: ʻWe have become more scientific in the way we work. Maybe this is not always as exciting as it used to be, but the final result is really impressive.ʼ
I canʼt help thinking as well that the high position of the engine may have skewed some of the research findings. This would have been less than ideal, raising the carʼs centre of gravity and placing a substantial mass high at the rear. It was, in retrospect, an odd way to build a test car that was intended to show the best way forward.
Interestingly the Porsche initiative wasnʼt all that different from the Grand Prix Lotus that Colin Chapman created for the 1976 season. His Type 77 had the following features, said Chapman:
ʻWe can alter the front track very easily by moving the whole of the suspension system out on the very simple sub-frame. It is also very easy to change the rear track. In fact, this is achieved simply by swapping over the rear wheels, which varies the track by four inches.
ʻWe can alter the wheelbase by up to ten inches,ʼ Chapman continued, ʻbecause there are five inches of adjustment at both the front and the rear, and so we can have either a long- or a short-wheelbase car. At the same time, depending upon how it is set up, it is possible to change the location of the centre of gravity, a fairly major adjustment which normally cannot easily be effected once any particular design of racing car exists.
ʻThe basic concept of the Lotus 77,ʼ concluded Colin Chapman, ʻapart from trying to produce a light, strong and efficient racing car, is to attempt to effect quite large
“IT WAS CRUDE… YOU COULDN’T GET THE FEEL OF A REAL CAR”
geometry changes very easily. This is not to say that we will go to a circuit and immediately start altering the car, although that could be done quickly.
ʻThe idea is that if we are going to a circuit where we know that a long-wheelbase car would probably perform best, we will set it up in the workshop as a long-wheelbase car. If we felt that a wide track would be beneficial for a particular circuit, then we will set up the car in that form. Then, if we found we were mistaken, we could very easily and very quickly change it.ʼ
Chapman first fielded his 77 on the wildly sinuous Interlagos track in Brazil. To suit it, the teamʼs 77s were built to minimum dimensions of both track and wheelbase. Mario Andretti found that his ʻhandles like a go-kart. I just canʼt get any precision with it.ʼ Ignominiously the Lotus team-mates crashed into each other early in the race, Ronnie Peterson leaving the team thereafter. Andretti persevered to win the seasonʼs wet final race in Japan driving a much-improved 77. In fact the 77 was the car that served as a test bed for the 78, which introduced ground-effect downforce to Formula 1 racing.
I donʼt know whether the PEP has survived. When I updated my Porsche history I was allowed access to the vast underground warehouse off a back street in a Stuttgart industrial estate that housed the Museumʼs overflow. I saw lots there that was interesting, including the flat-16 engines built for Can-am racing and the prototypes of the Type 989 four-door Porsche. But I didnʼt clock the PEP.
Exiguous as it was, it may well have gone directly to scrap. Just like my Tinkertoys. CP
Left top: The ultimate kit car, with removable front and rear subframes carrying the drivetrain and suspension. Removable bodywork gave instant access to the mechanical components Left: Then Porsche CEO Peter Schutz called the PEP ‘ugly as sin’ Above: The original concept called for the flat-six engine to be mounted above the transaxle, drive to which was via a series of gears. The Type 2696 also featured allwheel drive
Below: The Type 2696 would certainly never have won any beauty contests. There was more than a hint of 924/944 about its styling, but very little to link it with the 911 Right: One proposal was to run with the engine located above the transaxle, but the sole PEP (Porsche Experimental Prototype) used an air-cooled ‘six’ mounted conventionally behind the transmission
Above: Aesthetics were of little concern – the PEP’S raison d’être was as a development vehicle, a role in which it failed to excel…
Below: Colin Chapman tried a similar ‘adjustable’ concept with the Lotus 77 Formula 1 car, the foreunner of the ground-breaking Lotus 78 ground-effect car. It was more successful in its role than Porsche’s PEP…