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?

Total 911 - - Contents - Writ­ten by Lee Si­b­ley & Kieron Fen­nelly

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.

Pho­tog­ra­phy by Daniel Pullen

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

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