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…

Total 911 - - Contents - Writ­ten by Jo­hann Ven­ter

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.

Thanks

Spe­cial thanks to Ron Silke and red­star­race­way.co.za for the use of the track

Pho­tog­ra­phy by Michael Sch­mucker

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

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