END OF DAYS
Porsche’s new turbo charged future revealed
In half a century of 911 evolution, this latest update will rank amongst the most controversial: the Carrera is going turbocharged. Here’s the low-down on that - and other changes. #2016 #Porsche-911-Carrera-S-991.2
Dr Rerhard Mossle would rather let the car do the talking. On more than one occasion during our 48-minute interview I try to draw the senior Porsche engineer into making bold, cocksure claims for this revised and updated 911, but each time he simply replies: ‘You will see when you drive it.’
If ever a new car - or rather a new engine - had much to prove against a backdrop of such apprehension, this is it. The 911 Carrera is now turbocharged. In closing the book on five decades of tradition, Porsche has jabbed the ribs of the sports car purist who - for three very good reasons - will wonder if this could be the beginning of the end. Immediate throttle response, a serrated exhaust note and high crankshaft speeds have been central tenets of mainstream 911 engines since the original model arrived in 1964 and, owing to the fundamental way in which turbochargers work, all three of those principles could be at risk. Mossle’s quiet assuredness, though, is more convincing than any conceited sound bite.
The current 911, codenamed 991, arrived three years ago complete with its own breaks from tradition, and this facelift is intended to keep it fresh and competitive for the final few years until a replacement arrives. The big news, of course, is the switch to turbocharging, although significant revisions have also been made to the chassis, bodywork and cabin. The facelifted Carrera and Carrera S will arrive in UK showrooms before the end of the year, in both coupe and Cabriolet body styles, with four-wheel-drive versions to follow within six months.
By introducing the new turbocharged engine on this facelifted model, Porsche has given itself a head start on the 991’s replacement, which is due in 2019, and spared itself from having to develop a complicated new powertrain and an all-new platform at once.
Asked if he can understand the apprehension that some will feel about the move to forced induction, Mossle is emphatic: ‘Yes, of course I can! The normally aspirated six-cylinder boxer is a famous engine in the 911, but we face some challenges, not only in terms of fuel consumption and emissions, but also from our competitors. When you look at our competitor cars, like the Mercedes-AMG GT S or other cars with turbocharged engines, it’s getting harder to stay close to them with a normally aspirated engine.
Porsche isn’t just responding to the ever more stringent emissions regulations set out by the European Union and other legislative bodies around the globe, then. It’s also doing what needs to be done to keep up with the state of the sports car arms race in 2015, which, regrettably or otherwise, has reached a point where a naturally aspirated six-cylinder can no longer be competitive.
Both the new Carrera and Carrera S use an all-new 3-litre, twin- turbo engine, still with six cylinders arranged in a boxer formation. In terms of displacement, this is the smallest engine fitted to a 911 since the SC ceased production 32 years ago, but in terms of power output the mainstream 911 has never been more potent. Torque output, meanwhile, has gone through the roof.
Both versions boast a 20bhp increase over their naturally aspirated predecessors, to 365bhp for the Carrera and 414bhp for the Carrera S. Peak power in each model arrives at 6500rpm, with the red lines set at 7500rpm. Maximum torque on each model has risen, by 44lb ft on the Carrera and 45lb ft on the Carrera S, resulting in 332lb ft and 369lb ft respectively - but it’s now delivered from 1700rpm right up to 5000rpm. To put that in context, the prefacelift Carrera S delivers its peak torque at 5600rpm, which means the new model will be in a different league in terms of flexibility and muscularity from low engine speeds.
The turbochargers are supplied by BorgWarner. They’re fixed- vane units rather than the more advanced variable-vane items used by the 911 Turbo, and boost at 0.9bar in the lower-powered car and l.lbar in the more powerful model. The intercoolers are mounted within the bulging wheelarches and are fed via the air intake atop the central engine cover.
With more power than ever, the 911 Carrera is faster than ever, too. The base model will crack 62mph in 4.2sec when equipped with the optional PDK gearbox and Sport Chrono Package; that’s two-tenths quicker than its equivalent predecessor. The Carrera S dips below four seconds for the first time to record a 3.9sec dash (again with PDK and Sport Chrono); that’s another two-tenths improvement. Top speeds are now 183mph and 191mph respectively.
Fuel efficiency is another point of progress. With PDK, Porsche claims the Carrera will manage 38.2mpg on the combined cycle and the Carrera S 36.7mpg, which represent improvements of 3.8mpg and 4.2mpg respectively. ‘When it comes to fuel efficiency, Porsche is clearly ahead of the competitors now,’ reckons Mossle.
The benefits of turbocharging are very well documented, but so are the drawbacks. The mass market will equate more performance and improved fuel efficiency with progress, but it remains to be seen how cleverly Mossle and his colleagues have nurtured those less quantifiable characteristics that can make an engine truly exciting rather than merely effective. As Mossle said himself, we’ll find out for certain when we drive the car, but it’s clear that the engineering team did make a priority of response, soundtrack and excitement. ‘We tried to model a normally aspirated engine and avoid turbo-lag as much as possible/ he says. ‘A lot of detail work has gone into the system to improve response. For instance, when you come off the throttle the turbos keep spinning, so they are running at a higher speed when you get back on the throttle. We also have a new sports exhaust system that sounds really good. Yes, it’s different to a normally aspirated engine, but it sounds better than the 911 Turbo, more emotional.’
On the thorny subject of turbocharging, Mossle has the last word: ‘I think there will be a lot of discussion in the next half-year about it, but (ultimately) customers will always want the faster car.’
The manual gearbox faces a similar threat of extinction to the naturally aspirated engine in the world of the performance car, but in the Carrera it lives on. Was there pressure to ditch the manual? ‘We had discussions, of course,’ says Mossle, ‘because our manual installation rate worldwide is about ten per cent. It’s a kind of USP (in this sector) now. It’s not the fastest gearbox when you go on a racetrack, but it makes a lot of fun and that’s important for us. This weekend I drove a Cayman GT4 and I didn’t miss the PDK.’
The manual gearbox, still with seven speeds, gets new ratios to suit the new engine’s power and torque delivery. It’s also been beefed up to cope with the extra torque output, but the PDK transmission is unchanged, save for the ratios. Drive is still distributed between the rear wheels by a limited-slip differential - purely mechanical in the Carrera and electronically controlled in the Carrera S.
With a turbocharged engine comes weight. The new unit is 40kg heavier thanks to the turbochargers themselves, plus the necessary cooling and plumbing. Around 10kg has been offset by weight savings elsewhere in the car, but there is now more weight over the rear axle. As a result, weight distribution has moved rearwards by half a percentage point to 38:62 front to rear, which has required a complete overhaul of the chassis settings. Notably, the spring and anti-roll-bar rates on the rear axle have been turned up.
The rear tyres are now 305mm in section at the rear on the S model rather than 295mm, while four-wheel steering has filtered down from the Turbo and GT3 models as an option an the S. At low speeds the rear wheels turn in the opposite direction to the fronts to reduce the car’s turning circle (by 40cm), but above 50mph they turn with the front wheels to improve stability. With that added rear-axle stability the engineers have been able to make the steering more direct around the centre point, by 10 per cent, to make the front axle more responsive. ‘We have more grip on the rear axle so we could go a bit sharper on the front,’ explains Mossle.
The steering system itself is still electronically assisted, but Mossle claims it’s been improved dramatically since the original iterations of 2011, with lessons having been learnt during the development of competition cars as well as the GT3 and RS versions.
The brake pads are now a little bigger to deal with the added performance, and Porsche Active Suspension Management is standard fit. The vast majority of buyers were specifying it anyway, apparently, and as Mossle notes, ‘a sports car in this sector should have the best suspension technology available’.
As a direct result of the turbocharged power unit, the new tyres and the chassis revisions, the new Carrera S is six seconds faster around the Niirburgring than the outgoing model, posting a time of 7min 34sec. Impressively, that’s the same time Porsche claimed for the 997-generation GT2.
Visual updates are limited to revised bumper designs, new headlight and LED daytime running light layouts, vertical slats on the engine cover, more stylised rear lights and a new placement for the exhaust tips, plus a cleaner door handle design and new wheels.
The frontal air intakes now feature active flaps, which close in certain conditions to improve aerodynamics and therefore fuel efficiency. A front axle lift is now available, as it has been on the GT3 for some time, although the new system is 3kg lighter and offers 40mm of added clearance rather than 30mm.
Within the cabin is a new steering wheel, while a smaller, 360mm GT wheel is available as an option, which features a new 918 Spyder-inspired switch for adjusting the car’s chassis and drivetrain modes. The fourth-generation Porsche Communication Management system is introduced here with a multi-touch screen, a smartphone style menu system and Apple CarPlay preparation.
UK prices are confirmed at £76,412 for the Carrera coupe, £85,857 for the Carrera Cabriolet, £85,253 for the Carrera S coupe and £94,648 for the Carrera S Cabriolet.
The prevailing technologies change, Porsche responds and we traditionalists declare the end of days. It’s a story almost as old as the 911 itself. Looking back to the 1998 introduction of the 996-generation model, which was a comprehensive sea-change for the 911, it now seems entirely logical that Porsche switched from air- to water-cooling, despite the protestations of the purists. A modern performance engine cooled entirely by air is more or less unthinkable now and perhaps, with time, the same might seem true of normally aspirated engines, as frightful as that prospect might sound.
However, Mossle suggests the normally aspirated 911 might not yet be dead (putting to one side the GT models for a moment, which won’t adopt turbocharging in the foreseeable). There will never be another series-production normally aspirated 911,’ he says, ‘but maybe we will do some special-edition cars.’
Make no mistake, with the introduction of this facelifted model something has been lost from mainstream 911s forever. With the best turbocharged engine the world has ever seen, Porsche could mitigate against that loss to some degree, but no matter how responsive the new engine is and no matter what exhaust sorcery has been deployed, it will not match the outgoing naturally aspirated power units for pure, red line-chasing drama. It is the end of an era, but it’s also the start of a new one.
PORSCHE AND TURBOCHARGING
If any manufacturer is well positioned to navigate the automotive industry's pitfall-ridden journey towards widespread turbocharging, it’s Porsche. The factory first dabbled with the nascent technology in the early 70s. Having been roundly thumped by McLaren in the Can-Am series for several years, it introduced a turbocharged version of its 917 for the 1972 season, which would go on to dominate the championship for two years. Turbocharging would become a mainstay of Porsche’s competition models, with the 935 and the multiple Le Mans-winning 956 and 962 all using turbochargers. Today, the 919 Hybrid is also turbocharged.
Porsche’s first turbocharged road car was the 911-based 930 Turbo of 1975. With the technology still in its earliest days, the 930’s 3-litre engine was laggy and unresponsive, characterised by an unpredictable rush of boost halfway through the rev range. With every Turbo model that followed, though - through 964. 993.996.997 and 991. plus various rear-wheel-drive GT2 models - Porsche refined the art of turbocharging.
The introduction of variable turbine geometry has been one of the biggest advances in turbo technology. Porsche first used it on the 997-generation 911 Turbo of 2006. By changing the vanes’ angle of attack, the turbos gave better response at low engine speeds without compromising performance at higher speeds.
Today, turbocharging features across Porsche’s model line-up. from 911 to Macan. Cayenne and Panamera. A four-cylinder turbo unit is in development for use in the Boxster and Cayman sports cars.
A BRIEF HISTORY OF TURBOCHARGED 911s IN EVO
The advent of the turbocharged 911 Carrera might seem rather scary. A travesty, even. But a jog through the evo archive serves as a reminder that over the years some of our favourite 911s have had their induction forced.
Way back in issue 003 there was a memorable jaunt with a 993 GT2. and a Viper GTS-R. to Le Mans. David Vivian described the GT2’s steering as having ‘enough feedback to fill a book’ and noted the bark of the Porsche's exhaust turning bellicose at around 4000rpm, just where it got into its stride. Justin Bell, who brought the Viper along, thought the GT2 was relatively easy to drive, but then he was sportscar world champion.
Metcalfe running a black 993 Turbo (whose 408bhp will be overshadowed by the new Carrera S) in Fast Fleet for 18 months. The numberplate C8 UFO always seemed appropriate for the otherworldly speed that it was capable of. yet it also served as an everyday car for family Metcalfe, transporting children and even, memorably, a Christmas tree about the countryside. A more modern incarnation of C8 UFO. a 997 Turbo with a manual gearbox, would be something I would absolutely adore as an everyday car. Huge pace, surprisingly lairy, yet also remarkably comfortable. A wonderful thing.
In more recent times, who could forget the incredible 997 GT2 RS. The GT3 RS might be the purer option, but there is no doubt which is the faster. And the scarier. Andy Wallace famously got out of a GT2 RS, pointed at it and said: 'That, must be the best road car ever. The steering, damping and traction are incredible. And that engine... I mean, that is performance.'
Then there are the oddballs - the Ruf CTRs, the GT1s, the 959 - all wonderful cars that we have adored in their own particular ways. And turbocharging is an intrinsic part of each one of them, whether it be the almighty shove of a Yellowbird arriving on boost or the runaway- train feeling as the second of the sequential turbos in a 959 comes in at 4500rpm.
As this brief reminisce hopefully shows, turbo'd 911s have always been exciting and as much a part of evo As any GT3. No, they don’t have the soundtrack, but whether it’s the slight terror of trying to get on top of a rear-wheel-drive variant or the bewildered awe instilled by the cross-country pace of a four-wheel-drive version, they certainly hold your attention. Almost every article we’ve written about a turbocharged 911 talks about squeeeeezing on the power. Adding forced induction and really testing the legendary traction of the rear-engined layout alters the character of the car and makes you drive with a different mindset. Given what’s gone before, we’re rather excited to see what the 991.2 holds.
Far left: 993 GT2 (and a Viper) in evo 003. Left: 997GT2RS thrilled-and scared. Below: Metcalfe’s 993 Turbo and year-2000 Xmas tree. Main pic: 997 Turbo a Catchpole fave.
Right: new bumpers, headlights and wheel design help mark out the turbocharged Carrera, as do vertical slats on the engine cover and closer-together exhaust pipes (see previous spread).
TECH DATA #2015
PORSCHE 911 CARRERA S (991.2)
Engine Flat-six, 3 litres, twin-turbo
Power 414bhp @ 6500rpm
Torque 369lb ft @ 1700-5000rpm
Transmission Seven-speed manual ( #PDK
option), rear-wheel drive, LSD, Porsche Torque Vectoring
Front suspension MacPherson struts, coil springs, #PASM
adaptive dampers, anti-roll bar
Rear suspension Multi-link, coil springs, PASM adaptive dampers, anti-roll bar
Brakes Ventilated and cross-drilled discs, 340mm front, 330mm rear, #ABS
Wheels 8.5 x 20in front, 11.5 x 20in rear Tyres 245/35 ZR20 front, 305/30 ZR20 rear
0-62mph 3.9sec (claimed, with PDK and #Sport-Chrono-Package
Top speed 191mph (claimed)
Basic UK price £85,253
On sale December 2015
THE ELECTRIC POWER STEERING HAS BEEN IMPROVED WITH LESSONS LEARNT FROM THE GT3 AND GT3 RS
Above: optional steering wheel has a 918 Spyder-style driving mode switch (just below the right-hand spoke); Infotainment system has been updated and gains a multi-touch screen and Apple CarPlay.