Same fiddle, different tunes

Less weight or more power? Your choice from Weissach

Two ways to spend over £60,000 on a new, rear-engined Porsche in hallowed 911 format are offered to those who value performance above all else. Both the Carrera RS Lightweight and 911 Turbo are wrought upon the basis of the current Carrera 2, but are radically modified over that 250 bhp start point.

Our pairing draw on conventional speed techniques – lower body weight for the RSL, turbocharging for its stablemate – to provide totally different driving experiences. However, they cover a timing strip at a very similar clip with 260 and 330 bhp respectively, thanks to a 528 lb disparity in their kerb weights. Both have sensational performance, statistically and subjectively. The RSL and Turbo are capable of 160 and 170 mph respectively, rushing from rest to 60 mph in five seconds . . . or less. Both achieve less than 20 mpg.

On the public road, this desirable pair are amongst the elite of practical performers. They can consume commuter convoys or motorways at such sustained pace that – traffic jams aside – a light ‘plane would be pushed to reduce your journey times in Britain. Yet their philosophies are totally different. The RS Lightweight has such a sternly strapped down chassis that only the committed heart of our readership or those with extensive vintage experience are likely to be able to stomach its rural ride in everyday use.

The RS draws on an older (1973) Porsche tradition for providing speed from lowered body weight, and our test car followed this specification to its Lightweight conclusion. Items such as manual window winders and thin side glass save approximately 10 per cent over the now admittedly plump Carrera 2. Those who cannot do without electric windows and stereophonic entertainment can opt for a Touring version that saves only 140 lb (around four per cent).

The Turbo is almost as old a Porsche concept (born in 1974 as a 260 bhp three-litre). It draws inspiration from the desire to make a practical supercar. More than 35,000 Porsches of all types reside in Britain. These two will be amongst the rarities. Porsche GB plans to bring in only 80 Turbos. No more than 100 rhd RS imports are planned, the Lightweight specification tested accounting for 80 of these.

UK range

We have two of the most expensive possibilities in British Porsche motoring at our disposal here. The 911 range now starts at £50,243.29, with the 3.6-litre powertrain. It has transmission choices from 4×4 to either five-speed manual or four-speed Tiptronic, the latter a £2707.50 option that MOTOR SPORT liked when fully tested early in 1991. Such transmissions are available in three bodies: Coupé 2+2: Targa and Cabriolet. In each case the latter demands most cash. The silly combination of Carrera 4×4 abilities and folding top demands £63,873.68. At £63,544 you have a choice in 911 Carrera RS motoring, the Lightweight we tested or the Touring. The Touring rather defeats the stark objectives of an RS, but is a lot more practical with its central locking, alarm system, electrically adjustable sports seats, powered windows and eight-speaker sound system.

In the rarefied financial stratosphere beyond £70,000, Porsche has a couple of ‘turbo-look’ alternatives to the real thing. They are the 911 Carrera 2 Cabriolet, with or without Tiptronic at £70,397.39 and £73,106.15 respectively. Finally we have the £78,318.74 Turbo, as tested. The bulk of our mileage was in an official demonstrator that was at auction on the appointed photographic day. Thanks to Claire Knee for persuading AFN in Chelsea to lend us a replacement.

Technical analysis

Dimensionally, the RS is considerably lower, slimmer of body (the wheel tracks are the same) and so much lighter that it can almost offset the Turbo’s 70 bhp bonus. The RSL is 528 lb lighter than the Turbo. How so? Porsche began by deleting some items, viz the luggage compartment carpet, underbody corrosion protection (the warranty is down to three years), fog lamp apertures (lightly plated over), door pockets, the majority of soundproofing and folding rear seats. Stereo sound equipment goes to the no cost option list, and the internal door handles are replaced by pull tags that are going to look very scruffy after several thousand miles, especially in the vilified test car pink. Removed on the electrical front are many items from the wiring harness (ie that which supports electric windows and so on). Also out are central locking, wiring and speakers, plus the usual standard burglar alarm. Positive steps included a pair of fixed Recaro lightweight seats (oddly finished in heavyweight leathers), thinner glass for all but the windscreen, and manual window winders. I found manual labour easy and would cheerfully dispense with electrical assistance on the standard car, too. The steel bonnet is replaced by aluminium and the lid swings open to reveal bare fuel tank, plus a master switch suitable for competition. Stark though these steps may sound, an RS still retains power steering, Bosch ABS and the electrically raised and lowered rear spoiler. Such features originated on the Carrera 4.

The rest of the 911 formula is modified to suit the RS’s competition aspirations, often drawing on the turbo for inspiration (ie mirrors, wheels and huge cross-drilled brakes). Yet it is important to note that parts are not necessarily interchangeable. For example, those similar looking wheels are made in magnesium on the RSL and have half an inch extra rim width at the front, whilst those of a Turbo are in cast alloy and widely available for the ‘turbo look’ styling exercise that Porsche is currently pushing prominently.

Similarly the drilled discs and the use of four piston calipers are all sales-catalogued as being in common, but the rear discs are different and the ABS naturally needed reprogramming to deal with such a light, stiffly sprung machine as the RSL. Porsche places great emphasis on the Carrera Cup racer’s similarities to the Lightweight road car. Our inside technical information tells us that the front and rear spring rates (490 and 600 lb in), Bilstein dampers and roll bars (24mm front, 18mm rear) are “purely those of the Cup cars”, which accounts for 99 per cent of the adverse press comment received in the UK. The compliance steer bushing of the rear trailing arms is tampered with to the extent of filling the rubber bushes with steel inserts and that harder bushes are used throughout the RS suspension.

An MAHA power test slip in the glove box of our Turbo demonstrator revealed the presence of 307 bhp at 5510 rpm and that the company would expect more than 25 per cent of that to be lost at the rear wheels. It still has the best part of 100 bhp per litre from a lazy 10 psi boost from a version of the flat six that is little changed to that of the previous 911 outline. We are told that some detail work was done to amend the electronic control unit to allow K-Jetronic and a three-way catalytic converter to co-operate. The official 320 bhp claim equates to that of the old Sport Turbo specification. Another 20 turbo bhp is claimed over that of the pre-1990 onward Turbo, but we understand that the RS had one powerful ingredient that has not been promoted in the catalogues. All the engines are built to Porsche’s closest factory tolerances, akin to a factory blueprint if you like. That painstaking procedure probably has more relevance to the extra 10 bhp claimed than the ‘official’ reason of an amended electronic control unit. The twin ignition flat six was also owed to the Carrera 4. The redevelopment of the boxer six cylinders from 3.2 to 3.6 litres was rated at 69.4 bhp/litre.

The two-valve-per-cylinder boxer six has 72bhp/litre in RS guise, a total output similar to the original three-litre turbo. Porsche may opt for quad valves in each cylinder to release more power in the future. For the present a small torque bonus is also claimed, albeit only 3 lb ft (200 rpm higher than the Carrera 2’s torque peak). In the 1987 model year a new gearbox (G50) came into 911 service. Adapted from the techniques used in the 959 — thus the use of dogleg shift patterns that would easily allow a six-speed modification — this allowed the Turbo to have a strong five-speed unit. In association with a hydraulic clutch it also allowed a much sweeter shift to late model 911 s and was adapted for use in both Carrera 2 and 4. For the RS it has notably shorter first and second gear ratios in recognition of the substantially reduced kerb weight. In the turbo application it had two overdriven high ratios to take advantage of the 170 mph top speed potential, geared some 3.6 mph/1000 rpm higher than the busier RS.

Action

Observing the two Porsches bumper-to-bumper at rest, their separate characters are apparent. The RSL squats close to the ground, refugee from a circuit paddock, and retains the classic 911 line, courtesy of the electrically retracted rear spoiler. The Turbo features a fixed whale tail that carries its enlarged intercooler and has gaps between tyres and arches that look like those of a Ford Escort by comparison to those of the RS. Cockpit comparisons highlight the essential differences in appeal, the Turbo plush in a manner that makes us uneasy on the ever-plumper 911, the RSL so stark as to bear references to a punishment cell, lacking even door handles. The black facia remains kith and kin to its predecessors, five black and white dials recording the red needle’s progress from rest to 300 kmh (180 mph) and 6800 of 7000 displayed rpm. Both RS and Turbo share official 6800 limits on the facia, but others used higher rpm to return their performance figures. The RS cabin is almost the better for its lack of equipment, for turbo items such as the small rocker switches for sunroof and rear wiper are well-hidden; the rear screen heater is actuated via a pull knob that is a stretch away on the central dash.

Then we encounter the impracticalities of daily RSL life: loading luggage into the enlarged rear compartment is rendered almost impossible by the fixed seats. Also, there is no interior light. So we used the glovebox survivor and puzzled as to why the cigarette lighter survived the lightweight process. A multiple function on-board computer for the Turbo covered five further functions. We did not appreciate the digital speed display (too small), but the average speeds were entertaining; we tended to rest on the boost display which recorded 0.7 bar maximum, rather than the 0.8 of its predecessor. If you feel cruel boost is available with maximum throttle in top gear from under 1800 rpm, but the bulk of the generously boosted torque curve (some 100 lb ft more than that of the augmented RS total) is placed between 2500 and 5000 rpm.

The computer readout proved accurate to within 1 mpg on cross-checked runs and emphasised that 20 overall mpg was well within motorway reach. The front tank with traditional nearside wing access swallowed consistent amounts at refuel time in both models. Consumption of unleaded fuels averaged fractionally under 19 mpg of 98 octane “super” in the RSL, or some 2.5 mpg worse in the boosted model, thus balancing the use of cheaper unleaded in the more powerful machine.

Most potential owners will be more interested in the performance achieved. Have no doubt that this pair are amongst the fastest of roadgoing devices, but their track acceleration similarities are not borne out on the road. Here, the RS proved king even over the bumpy terrain that forces you to back off as the slimmer 911 shies away from adverse cambers and skitters over bumps. On smoother going you have time to appreciate that the accessibility of normally aspirated torque – from 1700 to 6600 rpm, more than 70 per cent of maximum torque is at your disposal, enough to offset the crushing on paper advantages of the Turbo. The latter is also tied down by its taller gearing, as you can see in our flexibility test results, which show the RSL as the faster in all but third gear between 50 and 70 mph. The turbo starts to claw back the advantages you would expect of another 70 bhp and 131 lb ft of torque as speed rises. The weight penalty seems obviated by 50 mph, although the two are very close from 0-100 mph, when the turbo has managed to slip in a second between it and its less powerful brethren. Both managed enormous speeds on timing strip and are in that class which allows tremendous public road capabilities without the penalties of bulky bodywork that seems to surround 200 mph offerings. ‘Our’ RS was a nasty reminder of some of the failings that we all used to tolerate in the name of exceptional speed. It stalled repeatedly after cold starts and was not above falling silent upon an initial start or at slow crossroad approaches. The RS was the more exhilarating to use, yet the soundproofed civilisation and naturally quieter motor meant that the only one you want to use on a motorway network would be the Turbo. Any 911 remains noisy over many motorway surfaces, but whilst the Turbo is one of the best, thanks to its modest motor noise, the RS is so spiteful that only the magnificent 3.6-litre note of the RS redeems its heritage and sets the driver eagerly about the next round of social madness. The RS dislikes road joints (such as concrete slabs) with a ferocity that is truly frightening. Not since the Ford Escort XR3 have we been hurled about the tarmac with such noisy brutality. By contrast, the power steering is beautifully weighted and ultra rapid, turning the RS into a curve with a flattering precision that makes the driver beam. Guiding the Turbo is not so pinpoint precise (there must be some slop in the bushes), but like other current 911s it is a pleasure to use.

Over smoother going, the RS whipped through each corner with such fine consistency that only a Caterham Seven compares. The writer truly loved it, until the next minor road crest, followed by a sharp and bumpy corner, set the suspension skittering and the ABS pattering, voicing its disapproval of using the car for what it was intended for, albeit not on the kind of surface Porsche engineers have ever come across outside Weissach and their third world sorties. The turbo was not so happy in Thames Valley action, feeling sloppy alongside the RS, but around Wales (on Yokohamas rather than Bridgestones) it was everything we could have wished for in a road car. Tenacious beyond the point of good road sense, it never allowed the clammy hand of terror to immobilise your reactions (a feeling experienced so often in older turbos, mostly under track conditions). Turbo ride comfort on the same section tyres as those of the RS was reasonable, but that should be so. For the front springs of a turbo have a rate three times softer than the RS, and that of the back is more than twice as soft as that racing reprobate. The first Turbo spent a week around North Wales and Anglesey, and even managed a 50-mile seaside spell with three occupants, including the opportunity to drive an 81 year-old grandma. She thought it looked nice, accelerated too fast and lacked comfort compared to her departed 1927 Rolls. Meanwhile, the same RS was deployed on two occasions. To gain the perspective of a 911 regular on the controversial RS, we took it to meet our ’70s road tester Clive Richardson. Now on his third 911, he was as pungent as ever in his summary of RS character in motion. “The low speed ride is truly awful, and I was not impressed at first, especially as the engine kept hunting and stalling around idle. I was also unimpressed by the brakes, I am sure these RS brakes are better when truly hot, but in Britain the pedal feedback is not so good as mine.” Nevertheless, Clive warmly appreciated the addition of ABS and added that some of the slippier terrain we traversed would have forced a reduction in pace in the older car. There were several features about the RS which reminded him that Porsche had made some basic progress with the Carrera 2 “such as the repositioned pedals that give the clutch foot some rest in the extra space created around the centre console.” We were slightly surprised he did not rate the amiable gearchange above that of his 1987 Carrera Sport, until we researched the 1987 adoption of the aforementioned G50 unit.

After a stint that ended in gradually worsening wet weather (in which the RS can become traditionally wayward at the back), Richardson summarised that “Porsche has lost sight of its own tradition. The original ’70s lightweight RS was a machine to drive in all conditions. This is not. This is a car purely for driving pleasure. It is very much a live animal, I certainly enjoyed it. The motor is fantastic in third and fourth, but not so tractable as it should be, which I think was down to poor preparation of the engine at idle. I would not pay £63,000 for the RS against £50,000 for the Carrera 2, mainly because I could use a Carrera 2 everyday, but not an RS.”

Verdict

No road contest or track confrontation leaves you in any doubt which Porsche is the better for each purpose. The turbocharged 911 is now truly tamed, but remains magnificently muscular, an enticing proposition to use over any public road. The Turbo is the best all-rounder in the Porsche range significantly more civilised at higher speeds than the 250 bhp ‘entry level’ 911.

In current road conditions, the writer did not think the 911 Turbo provided a £28,076 advantage over the cheapest 911 Coupé. Yet he did feel that those in the position of choosing between this Porsche and the more obvious supercars from Lamborghini and Ferrari would vote for the former if they wanted to use it regularly. We would still unhesitatingly recommend the 911 Turbo to those who must have the top of the range model. There is a touch of overkill about the whole exercise, but it is only a whiff besides the 200 mph offerings being touted elsewhere.

If, on the other hand, you believe the whole Porsche creed, and nothing but the Porsche creed, the RS is for you. The RS Lightweight is a truly memorable driving experience in a world full of increasingly bland motor cars. Don’t take passengers. This is a truly selfish car that delights in shattering both road distances and any occupant. JW