SC to RSR
The Porsche RSR formula is hugely popular on the historic racing circuit in South Africa. We find out what it takes to build a race-winning example…
You've studied the real thing, but what's it like to build your own RSR replica? We find out with a trip to South Africa
Finished in Satin black with the ubiquitous Martini livery, this special 911 is a sight to behold. It started out as a more humble 1979 SC, and was raced in road trim in a handicap series from 2010 for three years. Enjoyed during the week as a daily drive and raced on weekends – in keeping with the early 911 philosophy – it was acquired in 2014 by Mark Shepherd, an ex-formula 1 powerboat pilot, with the deliberate intention of turning it into an RSR replica to campaign in historic racing.
Wikus Rust from R&D Motorsport, who had successfully carried out three other RSR conversions, was tasked with the build. Wikus explains: “The intention was to build a car that could achieve under 1:10.00 around the 2.4km Zwartkops Raceway, to be competitive in the pre-1990 Sports and GT class in the ‘Historic Racing South Africa’ series. This class is highly competitive with plenty of RSR replicas, all of which have not stuck to the RSR script in terms of engine output. Engine capacities have been increased to the maximum that the rules will allow.”
The initial focus was to make the car as light as possible; in standard trim it weighed 1,200kg. It needed to be reduced to under 1,000kg. All the steel body panels, the doors, front and rear fenders, boot and bonnet lids were replaced with the exact RSR panels in fibreglass from Exclusive Conversions – a Porsche composite specialist. To further save weight the sunroof was removed, and the exterior panel of the roof was replaced with fibreglass. It was also imperative to increase the horsepower. The engine was converted to twin-spark and the capacity increased to 3.8 litres. This was achieved by fitting 3.8-litre Mahle pistons, 102mm Capricorn barrels, Pauter performance con-rods, a 996 GT3 crank with Porsche Supercup cams and 50mm PMO carbs. To optimise the power output and to attain a more linear power band, Rust installed Bosch coils and an ignition module with a 964 twin distributor.
It’s a substantial power upgrade, but how is all that power transferred to the track? Even before our test drive, Wynand, the current owner, is quick to point out: “Initially we retained the 915 gearbox and fitted an AP Racing twin-plate clutch and Tilton pedal box. To facilitate higher cornering speeds we fitted Von dampers with coilovers, Polly bronze suspension bushes and Wevo Teflon engine mounts to cope with the lateral acceleration. A brake upgrade was also essential; upfront we installed 964 RS calipers and discs, and at the rear 930 discs were fitted while retaining the original calipers.”
Mark Shepherd only raced it for half a season. “When I bought it in 2016 it was a nice-looking car. It was finished in black and orange Kremer and
Samson tobacco livery, reminiscent of the 1973 Kremer RSR in which Clemens Schickentanz won the European GT Championship and Porsche Cup title. I, on the other hand, wanted to try something new, and put my own mark, my finishing touch, to the car. Wikus and I had lengthy discussions on livery and colour schemes that would work with the car. We considered the tried-and-tested silver paint finish with Martini livery,” Wynand says.
After a day of racing at Red Star Raceway, friend and fellow racer, Fred Konig, sent me an image of the Porsche 918 Spyder, finished in Satin black with the Martini Livery. I then did some research myself and found Porsche racing legend Rolf Stommelen in the first race of the newly formed World Sports Car Championship, at the Nürburgring ADAC 300km, on 4 April 1976. In the new Porsche 936, decked out in black with the Martini livery, Stommelen went on to set the fastest lap and a fifth place finish… and I just happened to find the right war paint for my RSR,” Wynand remarks.
This is obviously not Wynand’s first foray into racing. “I’ve been racing for three years. I started with a standard 1983 Porsche SC, which had a bit of an IROC look to it, with Martini livery. My debut was in historic pursuit racing – based on a staggered reverse starting grid where the slowest car starts first and the fastest car starts last. I was introduced to racing by my friend Wernher Hartzenberg; he took me for a spin in his 928 around Zwartkops Raceway. When we went into turn one without braking I knew I was hooked!
“I vowed that I would take my own car to the next track day. I did and flew off at turn five at Zwartkops, as my brake fluid overheated. I then turned to Wikus and declared we should turn the IROC into a race car.
“We did it in such a way that I could drive the car to the track and back, so we installed a bolt in roll cage, uprated the brakes and fitted semi-slicks. At a practice session at Red Star Raceway I happened to be on the track with the Sports and GT cars, and realised that they were not that much faster than me, so then I decided to move up into the Sports and GT class,” he affirms. Although the car was pretty much complete by the time he bought it, Wynand has added some useful additions in preparation for his championship campaign. “We’ve upgraded from the 915 five-speed ‘box to the G50 gearbox with a limitedslip differential and Wevo gear-shifter. The G50 is a much better gearbox and the Wevo gear shifter ensures for quicker, more accurate gear changes. I like to be aware of my surroundings on the track and therefore fitted 993 rear-view mirrors; it gives me much better visibility,” he says.
With two races left on the calendar, Wynand is placed second in the Sports and GT class for both the sprint and endurance titles. He’s optimistic about his chances in the Rsr-spec SC: “I’m up against a couple of fast Porsche… the racing is fierce and the pack quite tight! Having said that, we’ve just returned from Zwartkops where I managed to secure both the sprint races and the endurance race, so the championship is up for the taking.” Wynand continues, “Zwartkops is my home track, because of its proximity and because of the amount of races that take place there. It is also the track where it all started for me. I know the track very well and we always manage to achieve good results there,” he admits.
“Kyalami is the most enjoyable track, though,
4.5 kilometres of racing Nirvana! Last year we won one sprint race and the hour-and-a-half endurance race there, placing second overall for the day. The endurance races definitely separate the men from the boys; both the track and distance test your fitness and concentration levels to the maximum,” he says.
But what about the most demanding track? “Red Star Raceway is the most challenging. It’s
“The initial focus was to make the car as light as possible”
a 4.2 kilometre circuit. It is narrow, long, with an endless amount of corners – 13 turns, of which five are hairpins. It demands respect! Being fairly new, the surface is very good and it favours RSRS. I won both the sprint races in April this year and last year I won one sprint race from the back of the pack. For the endurance race last year I led the race until a side shaft broke minutes before the race ended,” he states with regret.
So where next with the RSR? “I would like to upgrade the rear brakes with AP discs and calipers and increase the performance with higher compression Mahle pistons. The thought has crossed my mind to go the Turbo route. It would require plenty of work, including making the car wider. It would definitely put us in class A with the ‘big boys’. In any case, we are not far off from class A at the moment. If I qualify under 1:08.00 at Zwartkops that would automatically take me into class A. At the moment I am doing 1:08.02,” he concludes.
With my helmet on and strapped into the passenger racing seat with the five-point harness, I can feel the acceleration of my heart rate. Wynand is a superb driver, and I’ve been in this position many times before, yet the excitement and anticipation is there just like the first time. My adrenaline is pumping!
The whine of the engine picks up and the acceleration pushes into my chest and thrusts me firmly back in the Sparco racing seat. Just out of the pits, within seconds he slams on the brakes into the hairpin which is turn one. Hard on to the accelerator and the power is immediate, allowing for the overtaking of two cars, one through an S-bend. All the while the distinguishing Porsche whine crescendos above the roar of the engine. The RSR bites into the apex of the hairpin, Wynand powersliding the rear through the latter half of this sharp bend.
And all too quickly our hot lap for this practice session has come to an end. What has become apparent is how physically intense it is to stay on top of this beast. Yes, the wide, sticky Goodyear rubber provides plenty of grip and the Wevo gear shifter makes for easier and quicker gear changes, yet it is far removed from today’s GT and Touring Cars, fitted with paddle shifts, driving aids and hydration for the driver. As we’ve discovered before in this magazine, the 3.0 RSR is the pinnacle of early 911 racing. Even in this replicated formula, the drive is no less intoxicating.
Special thanks to Ron Silke and redstarraceway.co.za for the use of the track
RIGHT Vents in the dashboard give away the SC’S true age, but revised tacho screams 3.0 RSR
BELOW Engine deviates substaintally from RSR spec, running a 3.8-litre capacity with a 996 GT3 crank and Supercup cams
BELOW This Rsr-inspired racer relies on 964 RS stopping power up front, with 930 discs at the rear