The RSR was the beginning of a racing journey which, via the 934, culminated in the indomitable 935. uncovers an example that’s raced as them all Written by Chris Randall. Photography by Daniel Pullen.
TIME HOP
1973 Porsche 911 2.8 Carrera RSR
This 911 race car is steeped in history, having raced in RSR, 934 and 935 specification throughout the 1970s and 1980s
Porsche has long boasted an enviable motorsport pedigree, and a large chunk of its success can be attributed to the 911. The car you see here has certainly played its part in the story, and we’ll return to that a little later, but first we should rewind to 1972 and the world of Group 4 racing. It was for that year’s season that the Commission Sportive Internationale (CSI) announced a change in the rules, with engines of more than three litres banned from the World Championship of Makes. That spelt the end of the 917’s participation, but Porsche had the perfect answer in the form of the 911 2.7 RS.
“Given the option code M491, an RS transferred to the Werks 1 building would become a 2.8 RSR”
Given the option code M491, an RS transferred to the Werks 1 building would become a 2.8 RSR, the enlarged 2,808cc flat six featuring a 92mm bore instead of 90mm along with larger valves and ports and more durable four-bearing camshafts. Both strong and reliable, the new engine produced 308bhp at 8,000rpm, accompanied by a raft of other mechanical upgrades including brakes borrowed from the 917 and lowered suspension that now featured coil springs in addition to the torsion bars. Bigger wheels and tyres were covered by enlarged wheel arches, and the aerodynamics were improved. A winning package straight out of the box, the Brumosentered car of Peter Gregg and Hurley Haywood claimed victory at the 1973 Daytona 24 Hours – though running in Group 5, as Group 4 homologation was not yet complete – followed by wins at the Sebring 12 Hours and the infamous Targa Florio later the same year. Constantly developed, it would morph into the highly successful 3.0 RSR that dominated various championships throughout 1974 and 1975.
But yet another change was on the horizon, the CSI revising the Group 4 rules yet again for the 1976 season. Not that it worried Porsche, a team led by Wolfgang Berger starting work on the new racer in 1975, a car now based on the 930 Turbo. With homologation requirements dictating that 400 examples needed to be built over two years it was the obvious choice, and constructed to Group 4 specification it became the 934 – the RSR name now dropped. The engine was fuelled by Bosch K-Jetronic injection, marking its first appearance on a Porsche racing motor, and there were revised camshafts, along with a pair of air-to-water intercoolers. With 1.4 bar of boost the result was a substantial improvement over the previous RSR, maximum power now claimed as 485bhp at 7,000rpm.
Driving through the 930 Turbo’s standard four-speed manual gearbox, albeit with revised ratios and lubrication arrangements and a limited-slip differential, the 934 still featured the 917’s brakes and centre-lock wheels. Applying the CSI’s equivalency formula of 1.4 for blown engines placed the new racer in the 4,001 to 4,500cc class, requiring a minimum weight of 1,120kg, but Porsche was well ahead of that particular requirement. Having easily achieved a fighting weight of 1,080kg with fairly minimal changes, engineers were able – not for the first time in a 911 – to add ballast in the car’s nose to finetune the weight distribution. In fact, such was the ease of the transformation to race car that the 934 also retained electric windows! Unsurprisingly the new model continued the RSR’s success, winning championships in Europe and America as well as taking Group 4 class wins at Le Mans in 1977, 1979 and 1980.
But that wasn’t enough for Porsche’s flourishing motorsports department. By the early 1980s Group 5 was on the agenda, and with an opportunity for even greater levels of modification, full advantage was taken by one Norbert Singer. The result was the 935, once again based on the 930 Turbo, a car that built on the experience gained with the dominant 934. While the major components of the flat six needed to be based on the production unit, the increased scope for alteration saw Porsche reduce the bore from 95mm to 92.8mm, giving 2,856cc, while the fuel injection was retained, along with the 934’s intercoolers, valves and camshafts.
Using the same 1.4 equivalency formula meant the 935 now came in below four litres, which in turn meant that the overall weight could be reduced to just 970kg. And with 590bhp to play with, the result was predictably rapid. Not that the engine was the only area that came in for significant changes, the torsion bar suspension now swapped for an entirely coil-sprung arrangement, while the rear set-up was substantially altered, allowing far greater levels of durability and adjustability. Anti-roll bars that could be adjusted from within the cabin were another new feature, and the 935 also looked very different compared to its predecessor, Singer spotting an opportunity within the Group 5 rules to equip the new racer with the flat nose that would later appear on some very special road cars. With a recipe like this it is no surprise that track success was a given, the 935 passing into Porsche’s motorsport folklore as one of the most compelling Porsche race cars of all time and giving rise to legends such as ‘Moby Dick’. Looking back, it’s hard to believe less than ten years separated the naturally aspirated and 911-silhouetted RSR with the powerful and bodykitted 935, the latter ceasing production at the factory in 1981, though privateers such as Kremer and JLP would continue to develop the car in the ensuing years.
Such is the magic – not to mention interchangability – of the 911, it was possible for one single race car to adapt and evolve through every step of this incredible journey through the 1970s and 1980s, morphing from RSR to 934 and then to 935.
It’s a fate that fell upon the very car you see in our pictures, which means it has a very interesting story to tell indeed. It’s been resident in the JFD Collection for the last 15 years, something of a Mecca for those fascinated by competition Neunelfers. Painted in its original colour of Signal yellow, this 2.8 RSR exudes the purposeful, hunkered-down look of the true racer, the simple cabin little different from that of any other road-going 911. Only the roll cage and Recaro race seats give away its track-focused intent, and it is circuits where chassis number 911 360 1099 has spent plenty of time. It was bought new by Mexican driver Juan-Carlos Bolaños, a talented racer whose results include a 9th-place finish in the 1975 Le Mans 24 Hours at the wheel of a Kremer Racing RSR – driving a Kremer 935 in the following year’s event ended in a DNF. The first competitive outing for the car here was the 1973 Nürburgring 1,000km, where it too recorded a disappointing DNF.
The 1975 season proved more fruitful, with a 4th-place finish at the 12 Hours of Sebring, but at some point over the next couple of years Bolaños parted company with the RSR. It ended up in the hands of Colombian driver Mauricio de Narváez, who campaigned the car extensively throughout the 1978 season, its best result a 5th place at Daytona. The following season would be even busier, the campaign beginning and ending at that same track, and while results would be mixed, it was there that the car recorded its best finish of 7th. Another busy race schedule for 1980 would see de Narváez repeat that result, this time at the Daytona 24 Hours.
Interestingly, he was another seasoned Porsche campaigner, driving a 956 at Le Mans for Joest Racing, a partnership that bagged 4th place in 1983. He would also win the 1984 Sebring 12 Hours in a 935, co-driven by Hans Heyer and Stefan Johansson.
The following year would be much quieter in terms of racing activity, and here our trail goes a little cold, but what we do know is that the car that had begun its career as a 2.8 RSR had been through a number of updates. Common practice given the cost of purchasing a brand-new racer, it was first upgraded to a 3.0 RSR before progressing to 934 and then 935 K3 specification. Fast forward to 1992 and now in the ownership of Conrad Casado, who had found the car in South America, it was sold to Porsche specialist Jim Torres of Burbank, California, who embarked on the unenviable task of restoring it back to its original 2.8 RSR incarnation. Then sold by specialist dealer David Mohlman to a client in the Far East, the car actually remained in the US until 19 October 2004, when it was purchased by the JFD Collection.
Already the owner of a number of fabled RS models, the current owner was looking for a usable race car that might eventually be used on the road, and had considered others before settling on this particular example. Perhaps the fact that his father had owned a yellow RS Touring in 1973 influenced the decision, but you only have to look at it to see how hard it would have been to resist the lure of this car. It now appears exactly as it would have done when it raced at the Nürburgring way back in 1973, though for the majority of the time between 1977 and 1980 it actually raced as #46. The circuit is exactly where it belongs, the JFD Collection taking full advantage of this car’s abilities at the likes of Spa, the Nürburgring, Magny-Cours and Abbeville.
“It’s the damn best 911 RSR ever built by Porsche, usable on the street and fast on the track” the current owner says. “It’s so easy to cope with as the clutch, brakes and steering are firm but not hard to operate, and it’s a wonderfully balanced car. Easy to set up and slide, the only way to take a corner is to set it up, be a little sideways at the apex and accelerate it sideways out of the corner. Driving this car is a very visceral experience.” It was at Abbeville where Gijs van Lennep recently got behind the wheel, leaving JFD full of respect for the skills of those that raced the RSR competitively.
But we’ve got slightly ahead of ourselves, as 2007 saw another twist in this RSR’s story. Having already received an e-mail from the car’s previous owner alluding to the fact that the original engine resided in southern Florida, October that year saw the JFD proprietor making plans to visit the third Rennsport Reunion. Those plans included a visit to Bruce Ellsworth at Klub Sport in Riviera Beach, Florida, and it was there that the original motor, 6930152, was eventually discovered.
Taken by Bruce as a down payment on a 935 engine that a client had asked him to build, missing components were collected over time so that a complete RSR engine could be built. Today it still contains a number of the original parts, including much of the valvetrain, although the pistons and cylinder barrels are new stock. A mere 46 years after making its track debut, this stunning RSR is once again a matching-numbers car and – crucially – returned to RSR specification, with meticulous detail taken even to place the decals and race number exactly as they were in period photos.
Today, the reborn RSR takes pride of place in the JFD Collection, and despite the collection containing some incredible Porsche examples, it is clear that this particular car remains special. “I feel privileged to have and be able to drive such an iconic 911. Much faster 911s have been developed since, but this one remains the essence of a race car,” its doting owner says. I don’t think we could have summed up the RSR better ourselves.
ABOVE RSR’s flat six was upgraded to twin plug specification as part of an overhaul resulting in a 98hp boost over a 2.7 RS. RIGHT This 2.8 RSR morphed into a 934 and then 935-spec racer, the same in principle as the cars here. BELOW RSR tachometer runs to 10,000rpm, with peak power arriving at 8,000rpm. LEFT RSR’s arches are much wider to accomodate nine and eleven-inch wide Fuchs.
THANKS Thanks to the JFD Collection for access to the 2.8 RSR in our pictures
2.7 RS v 2.8 RSR: the differences
Engine changes: As well as the increase in bore size, the 2.8 engine was fitted with 49mm inlet and 41.5mm exhaust valves. For the 2.7 these were 46mm and 40mm respectively. RSRs got twinplug ignition too.
Higher compression: It wasn’t just the increased capacity and intake/exhaust changes that were responsible for the 98bhp increase over the 2.7 RS. The compression had been upped from 8.5:1 to 10.3:1 for the RSR.
Bodywork and wheels: Featuring six- and seven-inch rims, the RS was the first 911 to get wider wheels at the rear. The RSR took things a lot further and wore nine- and 11-inch items, covered by wheel arches widened by 5cm.
Better brakes: Where the RS was fitted with ventilated disc brakes front and rear, the RSR borrowed its stoppers from the 917. That meant cross-drilling of the discs too, and twin master cylinders.
Suspension: There were notable differences for the RSR. Works cars got additional titanium coil springs, shorter rear suspension arms were fitted, and metal bearings instead of the rubber bushes used in an RS.
Cabin changes: The 8,000rpm tachometer was replaced with a 10,000rpm item in the RSR, which also got a standard roll cage and fire extinguisher system.
Model 2.8 RSR
Year 1973
Engine
Capacity 2,808cc
Compression ratio 10.3:1
Maximum power 319bhp @ 8,000rpm
Maximum torque 295Nm @ 6,500rpm
Transmission Five-speed manual
Suspension
Front MacPherson struts; torsion bars; additional coil springs
Rear Rear semi-trailing arms; telescopic dampers; torsion bars; additional coil springs
Wheels & tyres
Front 9×15-inch; 230/600-15
Rear 11×15-inch; 260/600-15
Dimensions
Length 4,147mm
Width 1,752mm
Weight 890kg
Performance
0-62mph 4.4sec
Top speed 189mph
