Duck-tails, stenciled names on doors, big fat rear tyres, Mary, Queen of Scots, and total domination―the 911 Carrera RSR 2.8, one of the most fabulous Neunelfers ever, comes to the Porsche Legends Pack …
The Porsche 917 was made obsolete at the end of the ’72 season: the car that had taken Porsche to its first-ever Le Mans overall victory―and then made it two in a row, crushing the dreams of Ferrari’s 512s―was chopped-up and sent over to the US to Can-Am where, turbocharged, it would carve out a whole new history for itself.
Back in Europe, though, Porsche―now excluded from the Word Sportscar Championship that it had dominated for three seasons with the 917 and its sister car, the 908 (both are in the Porsche Legends Pack)―was left with nowhere to race.
Fortunately, for a brand that saw racing as part of its DNA, the newly-formed Group 4-ruled European GT Championship was a series that Porsche felt they could explore, given they already had a vehicle that would slot into the rules easily: the Porsche 911 S.
Stock, the car was nowhere near the Ferrari 365 GTB “Daytona” (also in Project CARS 2) that would be their main competition, neither in terms of handling nor power. But as a building block, the 911 S was ideal―all it needed was an upgrade to racing spec.
Porsche began working on their new racing 911 (500 road-going cars were needed for homologation) in ’71 and, as always, the targets were weight-saving and finding ways to get more beef into an engine that was immediately upped from 2.4-litres to 2.7-litres.
Meanwhile, to get the extra power down―now in the region of 210hp, up from around 180hp―the rear tyres were fattened, resulting in the world’s first road car that would have wider tyres at the rear than the front.
With that done, Porsche then went about ripping out everything superfluous including the rear seats, padding, sound insulation, and even door handles (replaced by lightweight fabric tethers).
Then they covered the fat rear tyres with some super-sexy bulging fenders, replaced all the glass with lightweight material, and used fiberglass wherever they could get away with it. Even better than that, though, was the new “duck-tail” rear spoiler sitting on top of the engine―this, too, a first for a road-going car.
Then Porsche stenciled “Carrera” on the doors and rolled out their new car: the Carrera 2.7 RS―the 2.7 for the engine, the Carrera for the Panamericana race Porsche had won back in the ’50s with the 356, and the RS for Rennsport (racing sport).
The car was quick―0-100kmh in less than 5.6 seconds―and incredibly light, but the Porsche bean-counters back in Zuffenhausen were convinced it would be a total financial disaster for the company.
A road car, they said, that was stripped out and offered no comforts, and a road car, they said, that couldn’t even be sold in the US because it lacked emission standard papers, and a road car, they said, that didn’t even have a cubbyhole, nein, it was sure to be an absolute disaster!
The Carrera 2.7 RS debuted at the Paris Auto Show in 1972. After six days, all 500 projected models (needed for homologation) had been sold. The bean-counters, chastened, quickly got to work, upped the price by another eight hundred dollars or so, and promptly found they’d sold another 1,000 units!
With the 500 cars needed for homologation sold, Porsche then got to work on their race version―a car that was essentially the 2.7 but, taking advantage of the regs that allowed for modifications for racing, upped the engine capacity to 2.8-litres.
That small increase, coupled with witchcraft, saw the horsepower rise by about 100 to a whopping 310hp or so … in a car that weighed less than a 1,000kgs.
The car debuted in 1973 at the 24 Hours of Daytona. It smashed, dominated, and finished first. Then it went on to Sebring for the 12 Hours and did the same, but this time with even more dominance. By the end of the season, the agility, pace, power, and sheer beauty of the 2.8 Carrera RSR had made the 911 into one of the world’s most desirable sports cars, secured the championship in its first-ever season, and went on to become a legend that remains, to this day, one of the most popular cars in vintage racing around the globe.
Porsche 911 Carrera RSR 2.8―Lead Vehicle Artist Casey Ringley gets under the skin
Huge credit to the old Paul Frère books which just go into ridiculous on every racing model from the 1970s and were an invaluable resource putting this together.
The 2.8L flat-6 is good for 308hp@8,000rpm and drives the rear through a type 915 5-speed. There’s a big set of alternate race ratios, but the engine is smooth enough that you won’t often feel the need to adjust things per track. The standard ZF limited slip differential could be set for 40 percent or 80 percent lock; 40 feels good on ours as a baseline (6 clutches, 50° ramps).
RSR race models were stripped down to 900kg for a neat 40/60 weight distribution. This was the time when wind tunnels were just starting to see use in developing race cars, and the 911 proved particularly terrible at the beginning with upwards of 300lb lift happening at the rear axle in the initial tests.
The duck-tail addition helped balance that, and cut about 75 percent of the rear lift, but still left significant lift overall. Numerous other tweaks just didn’t work very well, resulting in a car with downforce on the front end, and lift at the rear, until the ‘Mary Stuart’ setup, which actually made useful downforce at both ends of the car for only a small drag penalty. (The Mary Stuart was the Martini Racing RSR that featured an innovative wrap-around duck-tail wing which reminded people of the high collars made popular during the time of Mary, Queen of Scots. Only two were built at the time.)
We’ve gone with that kind of configuration for our aero model as it just drives the best of the bunch.
Suggested suspension setup for the RSR was effectively identical to the street RS models, with zero camber at the front, -1° at the rear, a touch of rear toe, torsion bars of 18.8mm diameter at the front and 23mm at the rear with 18mm anti-roll bars at both ends.
Stiffness numbers make this look soft, but the car is so light that it all works out in the end. It does get faster if you make it lower and stiffer, but the relationship between stiffness and difficulty is quite direct on this car. Dampers are very similar to Bilstein valving spec for the real thing―100/220 on the front and 160/210 on the rear.
Brakes for the RSR came straight off of the 917 prototypes; more than adequate for the job!
I’m loving driving this thing. It’s easy to see why they are so popular for vintage racing―the balance of power and grip is great, and the steering feel works perfectly with the chassis balance to glide through corners with the rear-end hung out.
Top speed isn’t especially high at around 250km/h, but the lightness and handling make it a good match for the old Camaro and Ferrari 365.
Multi-class at Le Mans with this will be great fun; 911 giving all it’s got for 250km/h on the Mulsanne while the 917 and 512M blast by doing closer to 390km/h!