Carrera 3.0 RS v RSR
Developed for competition, their three-litre flat sixes would also be the basis of the 911 Turbo – but how does the road-legal RS compare to the race only RSR?
Porsche only made 55 worldwide, but how does the RS differ from its RSR sister? Total 911 finds out
The afternoon skies above are covered with a thick coating of cloud, their heavily saturated underbellies providing a dramatic setting over the Circuit d’abbeville. The rain holds off though, skirting around the track and, in miraculous fashion, dumping itself rather spectacularly onto northern France’s flat plains in the distance.
We’re lucky, because a dry track is very much needed for today’s test of some £3 million worth of classic Porsche 911s. Our illustrious pair in question hail from 1974, the first year of the Porsche impact bumper. Their engine capacities are 3.0 litres, the biggest of any 911 of the time and more than the rest of the range, which had only just evolved into 2.7 litres. These are no ordinary 911s though. Built for racing, the white car with gold ‘Carrera’ decals has the letters ‘RS’ emblazoned beneath a huge whaletail on its decklid, the Henninger brewery-liveried car next to it sporting the outrageously wide and vented body of the competition-only RSR.
Symbolising the pinnacle of Porsche’s road and race pedigree in 1974, these cars began a rich history in forming the basis for the 911 Turbo, and a period in which Porsche would go on to dominate competitions right around the planet. This was a pivotal moment in the Neunelfer’s history – and today we’re going to compare how they drive.
First, some background. The 2.7 RS turned out to be an unexpected retail success, but Porsche’s intention behind the original 500 built in 1972 was to enable homologation of a Group 4 competition version. Some 55 RSS were taken from the line and converted by Werk 1 to full-blown racers. Bored out to 92mm to make 2,807cc, the RSR was the first flat six to reach 300 horsepower and won the Daytona 24 Hours in 1973 before its homologation papers had even been completed. More wins followed during that year, but the 2.8 RSR was short-lived – in September 1973 the impact-bumper 911 was launched, so it was no longer based on current production.
Once again Porsche built a road-going RS model, the 3.0 RS, for homologation. However, as the company managed to have the 3.0 RS classified as a continuation rather than a new model, the homologation minimum was only 100 units; 109 were built. The engine was comprehensively reworked: the 2,993cc capacity was achieved by taking the bore to 95mm, while the crankcase was now made of aluminium rather than the more fragile magnesium that Porsche had long favoured for competition engines. Rods and crankshafts were tested to racing standards and special pistons contributed to a 9.8:1 compression ratio. With single-plug ignition and
mechanical fuel injection, this street version delivered 230bhp at 6,200rpm and 277Nm at 5,000rpm. The specification included a lightened flywheel, an external oil radiator and a limited-slip differential, although the stock 911 exhaust system was used. Revisions to the suspension involved thicker rear trailing arms and the torsion bar anchored by solid bushing. 18mm anti-roll bars front and rear were now adjustable, as were the front struts. On 15-inch wheels were 215 section front and 235 rear tyres. Brakes were essentially those of the 917 racer.
The body, like the 2.7 RS, had thinner steel panels and lighter glass. Its plastic bumpers were shaped to replicate the impact bumpers of the production 911s, while its rear wheel arches were flared. Two rear spoilers were supplied with each RS 3.0 – the rigid ducktail and, because the German highway authority had objected to this, the rubber-edged whaletail which, because it was less likely to hurt a pedestrian, had been approved for road use. Most RS 3.0s were finished in Grand Prix white with black edging, although a wide variety of shades were available. For example, there are just six right-hand-drive RS 3.0s, and they are all finished in a different colour. The cabin was almost identical to the ‘lightweight’ RS 2.7, with black felt covering metal surfaces. A 10,000rpm rev counter and absence of clock were the main changes from the standard 911 instrument panel, and provisions were made for installation of a roll bar.
At the time Porsche was thought very clever to have negotiated a minimum build of 100 when a normal homologation norm would have been
1,000 units. In 1974 the OPEC boycott slowed
Western economies and pushed up petrol prices so dramatically that governments everywhere imposed draconian speed limits. Fortunately the German restrictions at least were soon lifted, but the market for fast cars suffered – 911 sales were down 30 per cent. In retrospect it is a pity, if understandable, that more RS 3.0s were not made.
That basis for racing was of course turned into the 3.0 RSR. Clients who had already shelled out DM 65,000 for the RS now paid over half as much again for Werk 1 to transform the RS into a pukka Group 4 competitor. This was the most dramatic-looking
911 yet, and sales began promisingly when Roger Penske ordered 15 cars for his International Race of Champions. A brilliant innovation which had Formula 1 stars competing against the best American racers in equal cars, the four-race series was broadcast on US television. Appropriately the winner was Mark Donohue, on whose recommendation Penske had selected Porsche rather than a home-grown make in the first place.
The essence of the RSR was its flat six: extracting massive – by the standards of the time – and above all reliable horsepower from an engine it had been developing steadily for a decade was Porsche’s great strength. The three-litre was tuned to an impressive 330bhp at 8,000rpm, with torque measured at 315Nm. Much of the componentry of the RS engine was unchanged. The major differences for the RSR were twin-plug ignition and valves with polished ports; instead of the stock camshaft of the road car the old Carrera Six’s four-bearing higher lift cams were used. A second oil filter was also installed.
Breathing was also different – instead of an air filter the RSR ingested air through six trumpets and exhaled through twin-pipe exhausts unencumbered by silencers, which came together under the engine. A Fichtel & Sachs sintered-metal clutch took the drive to the 915 gearbox. Magnesium wheels were 15-inch with centre-lock hubs. Behind them were 917 brakes, and the suspension was largely that of the
3.0 RS, Delrin bushing at the front providing more precise geometry.
On the track the Group 4 RSR immediately sustained Porsche’s competitive record, winning the FIA GT Cup for Zuffenhausen. Third overall at Watkins Glen and fourth at Spa against much faster prototypes were impressive results. John Fitzpatrick
drove both Loos- and Kremer-entered RSRS to win the European GT championship, and the RSR also took the European Hillclimb and several national championships. The drivers liked it; Toine Hezemans, who drove for Georg Loos, said of the RSR: “It was brilliant, so balanced. It always finished. I was fifth at Le Mans and had two wins and two seconds in the rest of that season. It was my favourite race car, even more than the BMW 3.0 CSL.”
Like its 2.8 forebear, the 3.0 RSR’S career was short. Having launched – and homologated – the
930 Turbo for 1976, Porsche was working hard on the blown competition 911, the fearsome and intimidating 934. The 3.0 RSR would remain the most powerful naturally aspirated 911 until the 964 RSR in 1993, its place in Porsche history assured. But what’s it like to pilot, and how does it differ from the Carrera RS 3.0?
Back in Abbeville the Carrera 3.0 RS has been fired up and is warming through nicely on tickover. As a road car it has two seats inside, the rears being deleted, and so we take a pew alongside Johan Dirickx, owner of the two cars in question, who’s affixing his helmet and fastening his seatbelt. Pretty soon we’re ready to rock.
Heading out onto the 2.3-kilometre track, we steal an early impression of the 3.0 RS: it’s pretty bare inside, though there is carpeting, door cards and glass windows. It’s fairly loud but not unbearable, that familiar, low-frequency bellow of the 911/77 flat six permeating into the cabin as Johan starts to hang on to the revs.
What’s immediately evident is how much better the 3.0 RS is over a 2.7 RS. As regular readers may recall from our 2.7 v 3.0 RS test in 2016, the 3.0 RS feels like an entirely different animal to its original Rennsport predecessor. Benefitting from a greater surge in power lower down the rev range, the 3.0 RS doesn’t hang around, displaying a wonderful linearity in the way it delivers its power right up to the 7,200rpm redline. However, its chassis is its crowning glory. Benefitting from a wider track, stiffer suspension and better brakes, it’s quick to instil real confidence on the limit. Push all you like, the 3.0 RS remains so wonderfully composed, with little diving of the nose under braking or falling back so wildly onto its haunches under acceleration like you’d get in the 2.7 RS.
Today, from the passenger seat, those recollections have come flooding back as Johan glides the RS around the flowing corners at Abbeville. He’s pushing hard but the car just sticks to the tarmac, monstering the circuit with the conviction of a car much younger than its 44 years of age. The 3.0 RS really does excel in the way it handles. Easing off the gas for a cooldown lap, Johan is able to impart his own verdict. He too says the three-litre is a nicer car to drive than the 2.7 RS: “It has more torque, a more solid power delivery and it was built as a basis for racing, so the chassis is so much better,” he says, shouting over the bassy note of the flat six.
Returning to the pits, it’s time to swap RS for RSR. Johan’s team has already done a fine job of coaxing the car into life and warming it through, the process more comprehensive than the RS road car, blipping the throttle and incrementally raising the revs until the car reaches peak temperature. Its sound with each blip is wild – we can hear it over the 3.0 RS before we’ve even climbed out of it.
Inside the RSR, there’s no mistaking its race car credentials. There are no relative luxuries like carpet or roof lining now, replaced with a more consummate cage including door bars and, well, that’s about it.
“It’s a completely different animal,” Johan says, unable to hide the wry smile spreading across his face. As we’re about to find out, if the 3.0 RS is an evolution of the 2.7 RS before it, then the RSR is a quantum leap over the 3.0 RS.
Rumbling back out onto the track the RSR is a little lumpy, it not liking running at such low revs. The engine splutters a little. The ride is harsh.
And never mind sound deadening: the stones
flicking up into the wheel arches from those sticky Michelin tyres as we hunt for the racing line draws audible comparisons to what I imagine it’s like sheltering under a plastic bag in a hailstorm. This is going to be interesting. All of that is about to change, though… with a clear track ahead Johan buries the throttle in second gear, and all hell is let positively loose.
First, the noise: a higher timbre than the Carrera RS, the roar emitted from the RSR’S exhaust pipes builds quickly to a screaming crescendo before snarling and chattering violently on the over-run. Then Johan turns in and the RSR darts across the tarmac, its conviction and willingness to do so absolutely staggering for a car of such vintage. Balancing the gas into the apex, Johan then brings in the power, quickly followed by several inputs at the wheel to control the car’s tail. Despite those huge Michelin Classic Racing tyres the car’s rear just wants to spit us out of each turn sideways, and Johan has to be properly ‘on it’ to keep it happy. As he tells me later: “To be fastest you have to drive it on the rear axle – that is, no guiding it into the apex and then getting on the power, but hustling into the turn, hitting the apex and managing the drift under full power on the way out.”
Its weightlessness means this is a car determined to fight you all the way, but it’s so rewarding to pedal as a result. Its twin-spark engine is nothing short of ferocious, the power delivery brutal, its durability unrelenting right through the rev range. “It’s a beauty to drive,” Johan says afterwards, visibly exhausted from the workout. Its chassis too is intrinsically communicative, far more so than even some modern 911 machinery. It gives a beautiful predictability to the RSR – which is needed if you’re to have any chance of driving it fast and keeping it under control.
The RSR is a notable step up from the Carrera RS. It’s more aggressive and uncompromising in every single way, from its footprint, to its weightlessness, to its power delivery. The differences between the two are stark, the RSR doing an unbelievable job in making the 3.0 RS look somewhat tame by comparison. You could argue that gap is still evident in Porsche’s line-up today; though the 991.2 GT3 RS is now closer than ever to being a ‘Cup car with licence plates’, as factory driver Nick Tandy once proclaimed to us, it remains a far cry from the works RSR he campaigns in the IMSA.
Finishing up, we place the two cars side-by-side in the pit garage and retire for the day. It’s been a revelation. Who knew that two cars so intrinsically linked could be so unfathomably different? With few road rivals the 3.0 RS is one of the most exquisite
911s of its time, a benchmark not really usurped in Porsche circles until the 964 RS some 18 years later.
The 3.0 RSR’S racing legacy was much too short-lived, it hiding in the shadow of the mighty Turbo cars which Porsche brought to the fore a year later, but its drive should not be underestimated as one of the most visceral of the 911’s entire history. It might only be one letter, but that final ‘R’ hung onto the end of ‘RS’ gives rise to a whole new echelon of excellence in Porsche performance.
BELOW The 3.0 RS is a far superior Rennsport than the 2.7 RS, displaying a much better natural balance on track
ABOVE 911 Motorsport technicians complete final checks on the RSR prior to our excursion on track