The Legacy of Porsche 935 in Silhouette Racing History
The moment the 935’s flat-six fires up with a bark that rattles your ribcage, you understand why this car rewrote the rulebook for production-based racing.
It started with a loophole. A clever reading of FIA Group 5 regulations that Porsche engineers exploited with surgical precision . The result was a race car so dominant that it won over 150 races worldwide, claimed overall victory at Le Mans against pure prototypes, and remains the most successful production-based racing car of all time . This is the story of how the Porsche 935 turned “silhouette racing” into a Porsche playground.
TL;DR
The Porsche 935 debuted in 1976 as a racing version of the 930 Turbo, built for FIA Group 5 “silhouette” rules . Those rules required only that the car’s basic frontal silhouette match the production model — everything else was open to interpretation . Porsche’s engineers, led by Norbert Singer, exploited this freedom ruthlessly. The 935 evolved through multiple generations, culminating in the radical 935/78 “Moby Dick” with 845 horsepower and a 366 km/h top speed . Customer teams like Kremer Racing took the 935 to Le Mans overall victory in 1979 . When Group 5 ended in 1981, the 935 kept winning in IMSA for years afterward. Porsche revived the name in 2018 with a 77-unit tribute car based on the 911 GT2 RS .
Key Takeaways
- Group 5 “silhouette” rules were the key — only the front-view outline had to match the production car, allowing radical aerodynamic changes
- Norbert Singer’s loophole discovery — moving headlights to the front spoiler for a “flat nose” improved drag and downforce
- Over 150 race wins between 1976 and 1984, including overall victories at Le Mans, Daytona, and Sebring
- Kremer Racing’s K3 won Le Mans outright in 1979 — the first GT-based car to do so in decades
- The 935/78 “Moby Dick” was the ultimate expression — 845 hp, 366 km/h, and a shape that barely resembled a 911
- Always use performance features responsibly and follow local driving laws.
Understanding Group 5 Silhouette Rules
The Rule That Changed Everything
Group 5 was not a prototype class. It was designed for production-based cars that had been heavily modified for racing. The FIA called it “silhouette racing” because the cars had to retain the basic shape of their road-going counterparts .
But here is the critical detail: the rules required only that the frontal silhouette of the race car match the production car when viewed from the front . Everything else — bodywork, wings, axles, cooling systems — was open to modification .
Porsche engineers studied the rulebook and found an opportunity.
The production 911 Turbo had distinctive round headlights mounted high on the fenders. But if you moved those headlights into the front spoiler, the frontal silhouette — the outline of the car’s width and height — remained unchanged. The fenders could then be reshaped for better aerodynamics .
That single insight created the “flat nose” or “Flachbau” design that became the 935’s signature feature.
The Weight and Power Equation
Group 5 rules used a turbocharger equivalency factor of 1.4. That meant Porsche could run a 2.85-liter engine and have it count as a 4.0-liter for class purposes .
The minimum weight for the 4.0-liter class was 970 kg. Porsche’s engineers built the 935 at just 900 kg, then added 70 kg of lead ballast to achieve a favorable 47/53 weight distribution .
The 1976 935 produced 590 hp from its single KKK turbocharger, with a top speed of 340 km/h .
The Evolution: From 935/76 to Moby Dick
1976: The Original
The first 935 debuted at the 1976 Six Hours of Watkins Glen, run by the Martini-backed works team . Jacky Ickx and Jochen Mass were the primary drivers, with Rolf Stommelen and Manfred Schurti as backups .
The 1976 car still resembled a 911 from the front, with headlights in their traditional position. But the widened fenders, massive rear wing, and lightweight construction made it clear this was something special .
Porsche won the 1976 World Championship for Makes, though the margin was narrow .
The air-to-air intercooler setup initially ran under the rear hood. Mid-season, the CSI rule makers insisted the “whale tail” hood of the production 930 must fit. Porsche switched to an air-to-water intercooler, costing weeks of testing and half a million Deutsche Marks .
1977: Twin Turbos and Customer Cars
For 1977, Porsche replaced the single large turbocharger with two smaller KKK units. The change eliminated turbo lag and made the car far more drivable .
Norbert Singer explained the reasoning: “We wanted to eliminate the drawbacks of the large single turbocharger. Two smaller turbochargers respond more quickly, which means less turbo lag and more controllable power delivery” .
Porsche also began selling 935s to privateer teams. The customer cars were nearly identical to the factory versions, and they immediately became the cars to beat in IMSA, DRM, and the World Championship .
The 935 was undefeated in the German DRM between 1977 and 1979 .
1978: Moby Dick
The 935/78 was the ultimate expression of the silhouette formula. Nicknamed “Moby Dick” for its elongated white shape, it was built specifically for Le Mans .
Norbert Singer took full advantage of every loophole. The car was lowered by 10 cm below the production floor. The front and rear ends were completely redesigned with detachable panels. The wheelbase grew, the body stretched to 4.87 meters, and the driver’s seat moved to the right side for better weight distribution on Le Mans’ right-heavy circuit .
The engine grew to 3.2 liters and received water-cooled four-valve cylinder heads — the first time a Porsche 911-derived engine used water cooling .
Power output: 845 hp in sprint configuration, detuned to 750 hp for the 24-hour race .
On the Mulsanne Straight, Moby Dick reached 366 km/h — faster than the prototypes from Renault and even Porsche’s own 936 .
At Le Mans, the car qualified on the front row and led early, but engine troubles and excessive fuel stops dropped it to eighth overall. It won the 6 Hours of Silverstone in its only other major outing .
The 935 “Baby”
Porsche also built a lightweight version called the “Baby” for sprint racing in the 2.0-liter class of the DRM. The engine was downsized to 1.4 liters, and the car weighed just 750 kg. Every unnecessary part was removed — they even punched holes in the ignition key to save weight .
It won on its second entry at Hockenheimring and was then retired .
The Customer Racing Legacy
Kremer Racing and the K3
Porsche did not sell the Evolution models like Moby Dick to customers. But private teams developed their own versions.
Kremer Racing from Cologne built the 935 K3, which became the most famous customer 935. In 1979, driven by Klaus Ludwig, Don Whittington, and Bill Whittington, the K3 won the 24 Hours of Le Mans outright .
This was the first overall Le Mans victory for a customer team and the first win for a rear-engine car in decades . Second place went to a factory-spec 935 driven by Rolf Stommelen, Dick Barbour, and actor Paul Newman .
Dick Barbour Racing
Dick Barbour’s team, operating out of Garretson Enterprises in Northern California, fielded 935s in IMSA and at Le Mans. In 1979, Barbour, Newman, and Stommelen finished second overall at Le Mans in a 935, winning the IMSA class .
The car was built in Mt. View, California — a decal on the rear wing read “Made in Mt. View, California by Garretson Enterprises” .
The 935 continued racing in IMSA’s GTP category even after Group 5 ended in 1981, usually entered by smaller privateers who could not afford the new Porsche 956 .
Porsche 935 Generations Compared
| Version | Year | Engine | Power | Weight | Key Feature | Notable Result |
|---|---|---|---|---|---|---|
| 935/76 | 1976 | 2.85L Single Turbo | 590 hp | 970 kg | Original silhouette racer | Won 1976 World Championship |
| 935/77 | 1977 | 2.85L Twin Turbo | ~630 hp | 970 kg | Twin turbos, customer sales | Undefeated in DRM 1977-79 |
| 935 “Baby” | 1977 | 1.4L Turbo | 370 hp | 750 kg | Lightweight sprint special | Won at Hockenheim |
| 935/78 “Moby Dick” | 1978 | 3.2L Twin Turbo | 845 hp | 1,025 kg | Water-cooled heads, 366 km/h | Won Silverstone 6H |
| 935 K3 (Kremer) | 1979 | 3.2L Twin Turbo | ~800 hp | ~1,000 kg | Customer evolution | Won Le Mans outright |
| New 935 (2019) | 2019 | 3.8L Twin Turbo | 700 hp | 1,380 kg | GT2 RS-based tribute | 77 units, track-only |
The 2019 Revival
A Tribute to Moby Dick
In 2018, Porsche unveiled a new 935 at the Rennsport Reunion at Laguna Seca. It was a track-only special based on the 991.2 911 GT2 RS Clubsport .
The bodywork paid clear tribute to the 935/78 Moby Dick, with a flat nose, massive rear wing, and elongated rear. The engine was the GT2 RS’s 3.8-liter twin-turbo flat-six, producing 700 hp .
Only 77 units were built, each priced from approximately €701,948 . Every car sold quickly .
The new 935 featured details from Porsche’s racing history: LED rear lights from the 919 Hybrid LMP1, mirrors from the 911 RSR, and titanium exhaust tips inspired by the 1968 Porsche 908 .
Why It Mattered
The 2019 935 was not a homologation special. It did not need to satisfy any racing rules. It was pure tribute — a celebration of the most dominant silhouette racer ever built .
Porsche’s Heritage Moments series brought together five key 935 variants for the first time, with Timo Bernhard and Norbert Singer discussing the car’s evolution. Singer, the engineer who created the original, shared stories of the FIA scrutineering battles and the constant push to exploit the rulebook .
FAQ
What made the Porsche 935 so dominant in Group 5 racing?
Group 5 silhouette rules allowed radical modifications as long as the frontal silhouette matched the production car. Porsche exploited this to create a lighter, more aerodynamic, and more powerful car than any competitor .
How many races did the Porsche 935 win?
Over 150 races worldwide between 1976 and 1984, including overall victories at Le Mans, Daytona, and Sebring .
What is the difference between the 935 and the 934?
The 934 was built for Group 4 rules, which were more restrictive. The 935 was built for Group 5, which allowed far more modification .
Why was the 935/78 called “Moby Dick”?
Its elongated white body and massive fairings reminded fans of the white whale from Herman Melville’s novel. The nickname stuck .
Did the Porsche 935 win Le Mans overall?
Yes. A Kremer Racing 935 K3 won the 1979 24 Hours of Le Mans outright, driven by Klaus Ludwig, Don Whittington, and Bill Whittington .
What is the new Porsche 935?
A 2019 track-only tribute car based on the 911 GT2 RS Clubsport, limited to 77 units, with 700 hp and bodywork inspired by the 935/78 Moby Dick .
When did the Porsche 935 stop racing?
The last factory 935 was built in 1979, but customer cars continued racing into the late 1980s, including in IMSA’s GTP category .
Final Thoughts
The Porsche 935 was never supposed to exist. Group 5 rules were written for production-based cars, not for the kind of radical engineering Porsche unleashed. But Norbert Singer and his team read the rulebook differently. They saw not restrictions, but opportunities.
The 935 was a “think tank on wheels” — a car that evolved every year, each version pushing further against the limits of what the rules allowed .
It won because it was smarter, lighter, and more aerodynamically efficient than anything else on track. It won because Porsche understood that silhouette racing was not about building a faster version of a road car. It was about building a race car that happened to look like one from the front.
Fifty years later, the 935 remains the benchmark for production-based racing cars. Its legacy lives on in every GT3, every GT4, and every Porsche that carries racing DNA to the street.
What is your favorite 935 variant? The original, the twin-turbo, Moby Dick, or the Kremer K3? Share your thoughts in the comments.
References:
- Wikipedia (archived) — Porsche 935 History and Racing Record
- Porsche Press Kit — Porsche 935 (1976)
- Porsche Newsroom — World Premiere: New Porsche 935 (2018)
- Porsche Press Kit — 935/78 “Moby Dick” Technical Data
- Collectors Car World — The Motorsport Scrapbook: Porsche 935
- Supercars.net — 1978 Porsche 935/78 Moby Dick
- Paul Tan’s Automotive News — 2019 Porsche 935 Details
- Hemmings — Porsche Gathers the 935’s Greatest Hits
- Revs Institute — Porsche 935: The Old Warhorse
- Porsche Christophorus — Porsche Legends of the RaceTrack
- Collectors Car World — Porsche Heritage Moments: The History of the 935
- Porsche Museum — Le Mans Overall Victories
- Porsche Newsroom China — Six Things About the Porsche 935
- Bonhams — 2019 Porsche 935 Auction Details
