Porsche are to return to single-seater racing this season for the first time since 1964, with a programme aimed specifically at the Indianapolis 500, but taking in too the entire USAC calendar of at least 10 races. They will field one car and one driver, the Hawaian Danny Ongais.
The historic revelation came as the Indy car was wheeled on to the stage at the Stuttgart Hilton last month, prior to the presentation of the 1979 Porsche Cup. It is not an entirely new car, it is not an entirely Porsche car, but it marks the start of a long-term project which Porsche hope will reach a successful peak in 1982.
The protect is being run in conjunction with Ted Field’s Interscope team, from Santa Anna. and the first Interscope Porsche as shown to us in Stuttgatt was built around a 1979 Parnelli P6B, a five-year-old design which stemmed from the Lotus 72. It is powered by a development of the turbocharged, flat-six, four-overhead-camshaft, Porsche 935 engine reduced in size to 2,649.5 cc. (92.3 mm. x 66 mm.) to comply with the 2,650 c.c. limit on the USAC engine alternative chosen. Only one turbocharger is permitted instead of the two run on 935s, this KKK unit with Garrett Air-Research wastegate boosting at the regulation maximum of 60″ of mercury (14 1/2 p.s.i.). The compression ratio is 9:1 and the power output is quoted as 630 b.h.p. at 9,000 r.p.m. and 412 lb. ft. of torque at 6,400 r.p.m. It drives through a Porsche four-speed gearbox with dog engagement. As this flat-six cannot be used as a stressed member, a tubular subframe has been built on to the Parnelli monocoque to carry the engine and suspension. Suspension is conventional, with front and rear anti-roll bars adjustable from the cockpit.
Porsche’s Manfred Jantke revealed that the Parnelli is very much an interim, development chassis and that a brand-new chassis, designed jointly by Porsche and Interscope and built in Santa Anna, will hopefully make its debut in time for the Indianapolis 500 in May. If all goes well, two cars will be run in the 1981 season. Helmut Flegl, designer of the 928 chassis, is in charge of the project for Porsche, working in conjunction with Interscope’s Chapman, while engine development at Weissach is the responsibility of Valentin Schäffer, the engineer who developed the 935 engine.
The Interscope-Porsche appeared at Stuttgart with no sign of sponsorship and Jantke claimed that there was no truth at the moment in the rumour that Martini or Essex would enter USAC with Porsche: “Sponsorship is still open. We could go it alone but would like some financial balance.”
Two initial shakedown tests of the Indy car have been made by Ongais at the Ontario circuit in California, one at the end of October, the other just four days before the Press Conference.
Porsche had planned to enter the American series before the split between the USAC and CART factions. “We had completed development for the then current high-boost pressure regulations — the engine was giving about 900 b.h.p. — before the split. but because of the split we decided to hold fire and have lost two years,” said Jantke. The two organising clubs are still at daggers drawn, but Porsche chose the USAC route to guarantee an entry at Indianapolis. Jantke said it would not be feasible to contest both the USAC and CART series because differences in the boost pressures (CART’s is higher) and the use of movable skirts by CART would call for two distinct engine and chassis development exercises.
The Interscope Porsche uses fixed skirts in a broad vee below the monocoque, but it is not a full ground effect car. Improved ground effect with the fixed skirts will be gained in the new chassis by moving the engine higher and further forward in the chassis and moving the driver further towards the nose. Air flow over the engine is adequate enough to make intercoolers and the familiar Porsche fan unnecessary, but the Indy engine follows the 935 design of water-cooled cylinder heads, with radiators mounted in the sidepods.
Power outputs are much of a muchness in USAC, where the Cosworth DFX is prolific, but Porsche are hoping or an advantage in reliability and fuel consumption. USAC rules enforce a maximum fuel tank size of 40 US gallons (151.2 litres) and include a consumption formula of a maximum of 1.8 US gallons per mile. The fuel is pure methanol
Porsche will eschew their long-running Dunlop connection for the USAC series to make use of Goodyear’s ready-developed tyres and experience.
Le Mans with 924s
After dominating with the 935 and Porsche 936 Porsche will restrict their European racing activities in this first year in the decade to engineering development ready for the new Appendix J regulations forecast for 1982. To this end, the factory will enter a three-car team of 2-litre, turbocharged 924 Carrera GTs in the GT prototype class in the Le Mans 24-hour race. These will be based on the prototype racing car shown at the Frankfurt Motor Show. A production road car version is planned for release next August.
Porsche hope for a class win with the cars, Porsche’s first, front-engined works racing cars, which will run on Dunlop tyres, with drivers still undecided. The fight for a fifth Porsche outright win at Le Mans will be left to the host of privately-entered 935s.
Sponsorship for the factory cars at Le Mans is undecided. “We are moving into a new generation of Porsches in racing and would like more Porsche identity for marketing purposes,” Jantke told us over dinner. “So although we are still very friendly with Martini we might not tie up with Martini for Le Mans.” he said, adding, “Martini were very upset by the Lotus business and by their Formula One experience in general.”
No more 935s will be built by the factory, which has put a premium on the existing cars, still the most competitive weapon for the World Championship of Makes and the American IMSA series. “I thought about buying the Georg Loos 935 I had my three wins in this year,” John Fitzpatrick told us on the flight back from Stuttgart, “but when Porsche announced they weren’t going to make any more, the price went up another 100,000 DM!”
The popular “Fitz” is moving house from Solihull to San Diego in the New Year and has signed with Dick Barbour to contest the IMSA series in a 935. But he may have to commute regularly to Europe to drive a Kremer 935 in the World Championship of Makes, if current discussions reach a successful conclusion. — C.R.
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