Porsche 935

Porsche 935 – Sensational Racing Cars That Dominated Global Motorsport

What car looks like a Porsche 911, sounds like a Porsche 911, goes faster than a Porsche 911, but isn’t a Porsche 911? The answer to this not-so-ancient riddle is the Porsche 935. Slant-nosed, as big as a whale and very, oh so very turbocharged – the 935 was the quintessential Porsche race car of the 1970s and a car surpassing its 911 roots by a huge margin.

Beyond the 911-like body, the 935 was the first step towards the new direction for Porsche racing cars and the best car to ensure the position Porsche established with the 917, while also being a perfect test for exploring the potential of forced induction.

Undoubtedly, Porsche 935 stands among the most beloved race cars of the 1970s, so we’ll explore its roots, evolution, and racing prowess to see what made it so remarkable.

Testing the Porsche 935. Source: Porsche


Background

Prior to developing its own cars, the Porsche family was already deeply involved in the world of racing. Both Ferdinand Porsche and his son Ferry worked on some of the most memorable racing cars in the pre-WW2 era and their commitment to racing continued in post-war years as well.

Porsche 550 Spyder
Porsche 550 Spyder

Pretty soon into establishing the company, Ferry Porsche ventured into racing with the 550 Spyder, instantly making a mark on the tracks in Europe and the Americas. Apart from purpose-built race cars, Porsche was successful in transforming the 356 into a formidable racer as well. It didn’t take much to transform the lightweight sports car into a track weapon, so the 356 soon gained ground among the gentleman racers and smaller teams. Moreover, the 356 was also a basis for the ambitious Abarth 356B Carrera GTL, an in-class winner of the 1960 Targa Florio and 1962 12 Hours of Sebring.

Porsche 356 B 1600 GS Carrera GTL Abarth at Le Mans 1962
Porsche 356 B 1600 GS Carrera GTL Abarth at Le Mans 1962

When the 911 replaced the aging 356, it naturally became the next bedrock for gentleman racers to test their luck in various types of racing. The 911 went on road courses, endurance races, and rallies, racking up wins in its respective classes.

Now, as the discrepancy between prototype cars and potent sports cars grew, Porsche ventured into both types of race cars and it did with great success. The 917 was a car the company needed to finally get to conquer Le Mans and when its era ended, Porsche’s racing department made a shift towards the 911-based racing program.

Winning Porsche 917 at 1971 Le Mans
Winning Porsche 917 at 1971 Le Mans

In 1973, Porsche revived the Carrera nameplate for the 911 Carrera 2.7 RS, a homologation car for certain racing series which required a number of special cars to be built in order to enter the series. Soon after, the scarce 911 Carrera RS 3.0 saw the light of day as a way for Porsche to enter FIA Group 4 class.

Both these cars were used to homologate the 911 Carrera RSR, a full-on factory racing car. The RSR was a naturally aspirated race that famously won 4th overall and 1st in-class at the 1973 24 Hours of Le Mans.


Development

Meanwhile, Porsche started playing with forced induction, introducing the turbocharged flat-six Carrera RSR Turbo for 1974. The 2.1-liter car proved to be a competent racer, winning numerous events and scoring 2nd overall place at the 1974 24 Hours of Le Mans.

1974 Porsche RSR Turbo Carrera 2.14
1974 Porsche RSR Turbo Carrera 2.14

The reason for such a small engine was the 1.4 modifier to the forced induction engine displacement. That being said, a turbocharged 2.1-liter engine produced 1.4 times more power than its 3.0-liter naturally aspirated counterpart, so Porsche needed to downsize its flat-six to equal the 3.0-liter class limit.

The next to arrive was Porsche 934, a racing version of the newly introduced 911 930 Turbo complying with Group 4 rules. The 934 showed up for the 1976 racing season and was a stripped-down, lightened, widened, and stiffened take on the 930.

934 RSR Turbo – 1976
Porsche 934 RSR Turbo – 1976

Although quite potent, the 934 was still far from the true limit of the 911, as chief racing engineer Norbert Singer had an ace up his sleeves for the same 1976 season and its works team.

At the time, the FIA Group 5 rules stated that cars falling under it had to be based on production models, with the doors and the windows in unchanged positions, maintaining the silhouette of a foundation automobile. Everything else was open to free interpretation, especially in the power department. Porsche decided to create an über-911 race car by stretching the limits of the iconic sports car’s platform.

The 935 was a result of an evolution of both the 934 and the Carrera RSR Turbo which started out in 1976 but was much more significant in the 1977 and the 1978 seasons.

After fully developing the car for its racing team, Porsche offered the independent racing teams to continue improving the vehicle further.

Having said that, the racing car can be divided into three variants: the initial 935/76, the thoroughly revised 935/77, and the water-cooled 935/78 long-tail variant. On top of that, there are the K2, K3, and K4 evolution models developed by the ambitious Kremer Racing team. 


Porsche 935/76

Porsche’s racing department started out with a steel unibody and unchanged floor pan for the 935’s first iteration in 1976. However, taking advantage of Group 5 silhouette regulations, the development team ditched the metal panels from the 911, replacing them with lighter glass fiber ones, leaving only the steel roof

Porsche 935/76

At the very beginning of the vehicle’s production span, the car had an unchanged front fascia with round headlights, thus looking a lot like a regular 911 despite some aerodynamic changes to the front fenders. However, thanks to the genius of Norbert Singer who discovered a regulation loophole where fenders could be changed and modified, the 935 got its famous slant nose look.

By leaning and lowering the front end and by adding ventilation slits to the remodeled fenders, Singer and the team of engineers increased downforce and reduced drag, improving the cars performance. The obligatory headlights were repositioned to the front spoiler, completing the loophole’s exploitation.

The radical slant-nose greatly influenced the tuner scene of the 1980s and the 1990s, starting from Porsche’s own scarce Flachbau option to conversions by Kremer, Gemballa, DP, and more houses.

The rest of the body was modified quickly into the 1976 season as well, all in the name of optimal aerodynamic efficiency. The rear fender and bulging rear wheel arches which were initially reminiscent of the 930 were given a thorough makeover too, being replaced with extended panels providing a longtail aerodynamic profile and better cooling properties.

side of Porsche 935/76

Group 5 regulations proposed a minimum dry weight of 2,140 pounds and with the vehicle weighing under 2000 pounds, Porsche’s engineering department was free to redistribute additional ballast to optimize the car’s weight balance and improve its handling.

Behind the rear axle was the 2.85-liter KKK turbocharged flat-six, a re-engineered version of the 3.0-liter turbo flat-six from the 930. Due to the 1.4x multiplier for turbocharged engines, the displacement of the engine was decreased in order for the 935 to stay in the 4.0-liter class.

With the turbo pressure ranging from 1.35 to 1.55 bar and Bosch Kugelfischer mechanical fuel injection, the Type 935 engine was pushed to produce 560 horsepower at 7.900 RPM and 438 lb-ft of torque at 540 RPM.

The 12-valve flat-six was mated to a 4-speed manual transmission which sent the power to the rear wheels via spool differential sending equal amounts of torque to each wheel. The setup provided greater straight-line stability at the cost of increased cornering difficulties, further made more problematic due to a huge turbo lag.

cleaning the 935/76

To balance out the spool differential, the suspension consisted of cast rear swing arms on ball-joint mountings and front tubular wishbones with rising-rate titanium coil springs on both axles.

The stopping power had to follow, so the 935 got its braking system straight from the mythical 917; aluminum four-piston calipers on both axles gripped drilled and ventilated steel discs. The stance of the car was staggered with 16-inch BBS wheels at the front and beefy 19-inch wheels in the back.


Porsche 935/77

After the successful initial season, the 1977 variant of the racing car brought more advancements and it was also the first year in which Porsche offered the race car to private customers.

Porsche 935/77
Porsche 935/77 Source: By Anna from Grassau, Deutschland

The construction of the car went a few steps further from the construction of the basic 930 911 and the last season’s 935/76, so the 935/77 became a fully spaceframe car. The body was changed as well with the most prominent change being the revised rear aerodynamics with a radically altered wing with an integrated intercooler box.

Moreover, the engine was now twin-KKK turbocharged, but the increase in power output came at a cost because the flat-six suffered from head gasket issues.

The most interesting sub-variant of the 935/77 was its so-called ‘Baby’ version, called that way because of a significant decrease in the engine displacement. Porsche chairman Ernst Fuhrmann insisted on building this car to prove that Porsche could enter the sub-2.0 liter class of the DRM championship where BMW and Ford raced unchallenged by the full-sized 935.

This special car took just a few weeks to engineer and to fit the requirements, it had an air-to-air-cooled turbocharged 1.425-liter flat-six pushing 370 horsepower at screaming 8,200 RPM.

Being in a smaller class, the 935/2.0 had a 1,609 lb limit so the weight was extensively shed by removing the stock floor and changing much of the car’s construction to an aluminum tubular spaceframe.

1977 Porsche 935 Baby
1977 Porsche 935 Baby

The baby 935 featured a unique narrower body kit with two clever aerodynamically efficient solutions: the first was a rear wing with integrated air inlets on the C-pillar, while the other was rear-view mirrors integrated within the front fenders.

The 935/2.0 raced twice. Its first outing was at the Norisring where it didn’t finish due to overheating, but the second race was far more successful. With Jacky Ickx behind the wheel, the baby 935 won the DRM support race to the 1977 Hockenheim Formula One race, proving Fuhrmann’s point.


Porsche 935/78 Moby Dick

In its final development stage, the vehicle was yet again thoroughly reworked for the 1978 season and this time the changes were rather drastic.

The roofline was lowered and the body was transformed into a low-drag longtail racer and the car was almost completely detached from the 911 shape. Due to the extensive modifications, the weight went up but was also redistributed with right-hand corners in mind by moving the seat further to the right.

Moby Dick
Porsche 935/78 “Moby Dick” 

Whenever possible, the weight was shed by Singer’s clever loophole exploitation, so the floor of the Moby Dick was replaced with a fiberglass panel among other tweaks.

The engine displacement rose to 3.2 liters, the power going up to as high as 850 horsepower with the boost set to 1.7 bar and 750 horsepower when running on 1.5 bar. The revised engine had watercooled 24-valve cylinder heads and due to decreased height, the gearbox was mounted upside down, reducing the angle of the drive shafts.

To improve airflow and extract hot air from the brakes, the Moby Dick famously had high impact orange flat fans on the wheels, a feature first seen on the 935/2.0 version of the car.

Moby Dick. Source: Porsche

Privateer 935 Cars

Apart from factory-backed Martini Porsches, the 935 was bought by a large number of private racing teams primarily located in Europe and the United States. Out of many, two stood apart from the most: Joest and Kremer.

Upon finishing the development of the car and shifting towards prototypes, Porsche left the blueprints and offered support to Kremer and Joest to replicate the car and continue building its legacy further.

Porsche 935/76
1979 Kremer Porsche 935 K3 took overall victory in the 1979 24 Hours of Le Mans

After modifying the 935 to K1 and K2 specification in 1976 and 1977 respectively, Kremer Racing constructed K3 and K4 race cars benefitting from improved aerodynamics while revised intercooler systems helped decrease the notorious turbo lag. These evolutions of the vehicle made it handle better, ultimately resulting in the 1979 24 Hours of Le Mans overall victory.


Racing

In the 1976 World Championship for Makes, the Porsche started its 935 campaign strong, winning the 6-hour March Trophy at Mugello and the 6-hour Trofeo Ignazio Giunti at Vallelunga.

In the next three legs, the 935 was beaten by BMW 3.5 CSL, in part due to some tweaks Porsche had to perform under pressure from the competition.

In the final two legs, however, the car scored another two triumphs, winning the 1976 season.

4th overall at the 1976  24 Hours of Le Mans
Rolf Stommelen and Manfred Schurti in their 935 finished 4th overall at the 1976 24 Hours of Le Mans

The 1977 World Championship for Makes season saw a heroic performance, with the 935 winning every single event it entered.

Plagued with decreased reliability, Porsche Martini Racing won four events with its twin-turbo 935, letting private teams win the other five events in their 935 cars.

At the 1977 24 Hours of Le Mans, a privateer JMS Racing Porsche 935 won third place overall.

Porsche Moby Dick

In 1978, the famed Moby Dick raced only on four events. It had a dominant performance at the 1978 Silverstone Six Hours in May 1978 where Jacky Ickx and Jochen Mass won the race by 7 laps.

Yet the next outing at Vallelunga and a DRM race at Norisring weren’t even close with the car not being able to finish the events. These races were just testing grounds for Le Mans, yet the Moby Dick was plagued by problems, finishing eighth, behind three privateer 935 cars and a Porsche 936 prototype among others.

Dick Barbour entered two Porsche 935s in the special IMSA class at the 1978 24 Hours of Le Mans where the #90 car went on to win its IMSA class.

In the World Championship for Makes in 1978, the 935 won each event both as a factory race car and a private entry.

After the 1978 season wrapped up, Porsche turned its focus onto prototype racing, letting the 935 customers take over. That’s where Kremer rose to the top, with the highlight being a victory at the 1979 24 Hours of Le Mans, where the Porsche 935 K3 (chassis 009 00015) driven by Klaus Ludwig and brothers Don and Bill Whittington won the race ahead of Dick Barbour Racing 935/77A driven by Rolf Stommelen, Paul Newman and Dick Barbour, and another Porsche 935 K3 driven by Laurent Ferrier, François Servanin and François Trisconi.

935 K3 at Le Mans
Winning 935 K3 at Le Mans
poster

In the 1980 24 hours of Le Mans, the Dick Barbour Racing Porsche 935 K3 sported the iconic Apple computer livery. The white car displayed the brand’s retro rainbow motif on the hood, sides, and wing. On the back of the car was a sticker above the exhaust stating “Don’t upset the Apple Car.”

Apple car

The 1979 1-2-3 Le Mans victory was a phenomenal achievement and perhaps the 935’s greatest highlight, but that was far from its only accolade.

The 935 saw great success in international racing, winning the World Championship of Makes from its introduction in 1976 to 1979, dominating the Australian GT championship in 1982 and 1983, and also scoring six straight victories at the 24 Hours of Daytona from 1978 to 1983 and six victories at the 12 Hours of Sebring from 1978 to 1982 and in 1984.

In total, the 935 racked up over 150 victories in racing events around the world, adding to its cult status which spanned all the way to the late 1980s.


Legacy

Whether it was the factory 935 wrapped in its original Martini stripes, or Kremer’s Coca-Cola, Apple, or Vaillant livery cars, the 935 was without any doubt the car that marked the end of the 1970s. The iconic 911 shape was pushed to the maximum, and so were the limits of the venerable flat-six which later found its way inside of the 936, 956, and 962 trio.

The 935’s DNA was so strong that the company paid tribute to it by creating an ultra-exclusive modern homage in 2019. Between the original and the contemporary interpretation, the car served as an inspiration for another two über 911 derivatives, the 959 and the 911 GT1.

flames in exhaust

The 935 holds utmost importance in Porsche’s racing heritage by seamlessly mending the gap between the 917 and the 956, two generations of prototypes that left an everlasting mark on motor racing.

With that in mind, the 935 is another icon in Porsche’s star-studded universe and a car which ensured the company’s ceaseless position at the top of global motorsport in unmatched fashion.

Show Comments (8)

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  1. As a proud owner of “Porsche’s own scarce Flachbau option” (1985 Sonderwunsch Flachbau) I found this article a fascinating read. Thank you Norbert Singer! I found the Kremer 935’s the most interesting. They brought Porsche’s 935 to the height 911 forced induction racing.

  2. Fantastic article! Can you recommend a book or two that cover Porsche’s participation in racing, either up to the end of the 935 era, or the end of the 962 era?
    I saw a lot of these cars race in the ‘70s and ‘80s.
    Thanks again,
    Dave

  3. Good read however early in the article you refer to the 935 engine as a 24 valve, not true, the only 24 valve engine was in the Moby Dick car with the water cooled heads. All others were 12 valve and air cooled.

    Jerry Woods
    Builder of 935 engines from 1978 thru 1985

  4. Hey Jerry,

    Yes, I’ve made a mistake when writing the article. Thanks for your kind words and the correction. It must have been amazing to be working on these cars in its prime!

    Best,
    Djordje

  5. Do these books leave off the e in the link?
    It was said during the 935 era that driving a 935 would not. Guarantee that you would win but not driving one guaranteed you wouldn’t.

  6. Excelente resumen del desarrollo del 935 Turbo, un héroe de grandes batallas de Porsche. En el futuro sería bueno ahondar en las variantes técnicas que caracterizaron y diferenciaron a los 935 de Kremer y Joest.

  7. I was a high school kid in the late 70s one hour west of Daytona. Grew up watching the 24 hours starting on my 10th birthday February 4 1971. One of the races late in the 70’s I grab a large piece of Martini Porsche 935 fiberglass body work that had been tossed over the guard rail after some bit of drama. I cut out of the iconic Martini colors a silhouette of the 935 . Had it on my walls all through collage…not sure what happened to it ?