PORSCHE’S TINKER­TOY

Prob­a­bly the most un­usual pro­to­type Porsche you’ll ever see

Classic Porsche - - Contents - Words: Karl Lud­vigsen Pho­tos: Lud­vigsen Ar­chive

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…

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