Car reviews - Porsche - 911 - Carrera range
4 Sep 2008
WITH new direct-injection engine technology, significant suspension modifications and the introduction of a dual-clutch manual gearbox dubbed PDK, Porsche’s facelifted 997 is the most advanced 911 ever.
Available from September 20, it will also be the most expensive, with prices rising about $10,000. Excluding the extra equipment levels that most of the range now boasts, Porsche says the new 911s are only up by around 1.5 per cent.
Visually, the 997’s transition to Series II is subtle, with redesigned front and rear bumpers, revised headlights incorporating bi-Xenon headlights with washers and daytime LED running lights, and reshaped tail-lights being the most obvious.
Look more carefully and you may notice the newly designed wheel, exhaust outlets, door mirrors (which are now larger and double armed) and front air intakes, with the latter’s shape now more in harmony with the lighting/indicator panel above.
The all-wheel drive Carrera 4 (C4) models should be easier to spot now, thanks to the return of the 996 C4’s full-length rear reflector sited between the tail-lights, as well as silver-coloured front air-dam strakes. A big ‘Carrera4’ badge gives the game away too.
But it is under the skin where changes run deepest, resulting in one of the most changed 911s in the model’s 45-year run.
Leading the charge is a pair of new direct fuel injection engines espousing improved efficiencies for Porsche’s trademark water-cooled horizontally opposed six-cylinder boxer units. They are built at a new facility in Zuffenhausen, alongside the direct-injection V-engines introduced in the Cayenne SUV last year.
Again available in 3.6 and 3.8-litre guises, both feature an aluminium engine block (contributing to a 5kg lighter engine than before), four overhead camshafts, four valves per cylinder, variable valve timing (called VarioCam Plus in Porsche-speak), and dry-sump lubrication with an on-demand oil pump.
Goals for Porsche’s engineers was to create a new engine family (only the second-generation water-cooled flat-six units since mainstream 911 models abandoned air-cooled engines in 1997) that is significantly more compact, has a much lower centre of gravity, and can be flexible enough to increase or decrease in capacity from under around 2.5-litres to beyond 4.0. The old unit reached its maximum capacity at 3.8.
There are 40 per cent fewer moving parts thanks to innovations like a new timing chain technology and one-piece cylinder-heads with integrated camshaft bearings and guide cylinders for the hydraulic cup-tappets.
The engine’s power-unit rigidity is now 22 per cent better than before, to be able to handle the extra power of a turbo-charger in future iterations such as the one that is expected to feature in the upcoming 997 911 Turbo Series II in 2009.
Porsche has also introduced four special ‘scavenging’ oil pumps to stop oil from ‘slopping’ around inside the engine unevenly at more extreme cornering speeds and angles, improving oil circulation and effectiveness, and reducing mechanical friction, to the point where there is a two per cent fuel economy benefit.
The latest 911 engines also introduce a new air-intake manifold to aid power and torque accessibility, while new air filters last 30 per cent longer than before. A more efficient exhaust system also helps achieve a Euro 5 emissions rating.
The upshot of all these, as we reported at the 997 Series II global launch back in June, is a pair of powerplants that deliver the naturally aspirated specific engine output benchmark of 100hp and 110Nm per litre for the first time in a 911.
The all-new 3614cc flat six serves up 254kW at 6500rpm (up 15kW on the old 3596cc engine), while the Carrera S’ 3800cc secures 283kW at 6000rpm instead of the 261kW rating of the old 3824cc unit.
Peak torque, meanwhile, rises by 20Nm in either case – to 390Nm at 4400rpm and 420Nm at 4400rpm for the 3.6 and 3.8-litre respectively.
PDK stands for Doppelkupplungsgetriebe – a seven-speed double-clutch transmission with roots dating back a quarter of a century to when Porsche first developed the system (successfully) for motor racing – although the current item has ‘only’ been in development over the last nine years, according to Porsche’s powertrain program manager – 911, Thomas Krickelberg.
Today’s version is co-devised with specialists ZF, and – like the (completely unrelated) DSG item pioneered in a production vehicle by Audi in the 2003 TT V6 – differs from a conventional transmission by being a fully manual gearbox that comprises two clutches that activate two separate sets of pre-selected gear ratios.
Yes, the regular six-speed manual gearbox 911 (an Aisin-built unit now boasting a higher third-gear ratio in the interests of better official fuel consumption results) has a marginally faster top speed, but 911s packing PDK offer quicker acceleration – even when they’re not fitted with the optional Sports Chrono Plus pack’s launch control system.
Nevertheless, the Carrera S Coupe manual breaks free of the 300km/h barrier at 302km/h (up 9km/h), which is within a whisker of the 996 911 GT3 and 996 Turbo, while the Carrera S Coupe with PDK’s 300km/h top speed is 15km/h more than the old S Tiptronic.
Similarly, the regular 911 Carrera coupe manual will achieve 289km/h (up 4km/h), which is just 2km/h quicker than its PDK sibling and 7km/h faster than the outgoing 911 3.6 Tiptronic auto.
Of the rear-wheel drive 911s, only the Cabriolet 3.6 manual fails to breach the five-second 0-100km/h-acceleration time at 5.1 seconds (PDK: 4.9 seconds), with both the 3.6 and 3.8 manual coupes shaving one-tenth of a second over the Series 1 cars at 4.9 seconds and 4.7 seconds respectively.
Pick PDK and you cut another 0.2 seconds off these times for a 0.8-second saving compared to the old Tiptronic times, while another 0.2 seconds is sliced again if the Sport Chrono Plus’ launch control system is fitted, for a 0-100km/h result that is just 0.4 seconds shy of the 997 Turbo manual’s 3.9-second sprint time and 0.6 seconds for the Turbo Tiptronic.
Similarly, economy and emissions benefit too, with the 3.6 manual coupe using six per cent less fuel at 10.3 litres per 100km (previously 11L/100km), while the S equivalent is eight per cent more economical at 11.5 versus 10.6L/100km.
In the PDK guise the gains are even greater, with both the Carrera coupes 13 per cent more frugal - 11.2 down to 9.8L/100km for the 3.6 and 11.7 down to 10.2L/100km for the 3.8.
As a result, CO2 emissions fall by a similar margin, with the Carrera coupe manual nine per cent cleaner (266 versus 242g/km) and the Carrera S coupe manual 10 per cent better (277 versus 250g/km).
PDK versions of both 911 coupes emit 15 per cent less CO2 emissions – from 270 down to 230g/km for the 3.6 and 283 down to 240g/km for the 3.8.
Furthermore, all 3.6-litre manual models now score the 3.8-litre Carrera’s clutch, which features self-adjusting pressure technology.
Porsche has also modified the suspension and brakes for the 911 Series II, with revised springs, dampers and anti-roll bars across the range.
Of course, being Porsche, the technical changes are widespread, but perhaps the most obvious change for 911 aficionados is the inclusion of an additional stop spring on both the front and rear axles, which (controversially) eliminates the car’s famous nose ‘bobbing’ action.
Whether it’s a manual or PDK 911, buyers can now choose a mechanical limited-slip differential (LSD) with a 22 per cent locking action under power and 27 per cent locking action in overrun, to improve traction and stability through trickier corners or over rough surfaces.
Another option, this time on the base 3.6 but standard on all S cars, is a refined version of Porsche’s Active Suspension Management (PASM), which is said to enhance smoothness, dynamic performance and response thanks to the inclusion of new adaptive dampers.
It is available in PASM Normal (alternating from standard comfort to a firmer set-up according to how hard the car is being driven) or PASM Sport (hardest-setting dampers, with the entire car dropped by 10mm). There’s also a ‘special variant’ PASM Sport package available with unique active sports suspension, a 20mm ride-height drop and a mechanical LSD.
Meanwhile, C4 911s adopts the current 911 Turbo’s newer electronically controlled AWD system, which in turn was inherited from the Porsche’s Cayenne SUV.
Fitted as standard with a mechanical rear axle differential, this new electronic Porsche Traction Management (PTM) system replaces the viscous multi-plate clutch AWD system in the outgoing C4, for “...an even higher standard of driving stability, traction and agile handling”, according to Porsche.
According to Mr Krickelberg, PTM continuously shifts torque from up to 100 per cent rearwards to 100 per cent front-wards in extreme conditions, although in everyday driving its rear-to-front ratio is around 95:5. This compares to the outgoing C4’s fixed 60:40 split.
Otherwise, engine outputs are the same as the new C2, while the C4 offers up to 8.5 per cent more power and up to 12.9 per cent greater fuel economy than before, while lowering CO2 emissions by up to 15.4 per cent.
As before, the C4 is 44mm wider in the rear compared to the Carrera 2.
Regardless of whether it’s a C2 or C4, all 911s now have a new hill-hold device called Start-off Assistant, to keep the cars from rolling backwards at launch speeds.
Larger (now 330mm) disc brakes mean greater stopping ability than previously, with new callipers on the 3.6-litre models, while PSM-fitted cars now score Porsche’s new Brake Pre-Filling and Brake Assistant functions previously available only on the Carrera 4 and the Turbo for quicker and more powerful responses.
There’s also a new tyre pressure monitor.
Moving to the Cabriolet models, Porsche now uses a harder wearing material for the soft top, which still takes 20 seconds to open and shut and can be erected on the move at up to 50km/h.
The additional standard specifications offset the slight reduction in engine weight, with kerb weights increasing between 5kg and 20kg.
The Carrera coupe manual rises 20kg to 1415kg, while the PDK version is 10kg heavier than the Tiptronic S version it replaces at 1435kg. The Carrera S coupe manual is 5kg heavier (1425kg), while the PDK version is up the same amount, to 1460kg. The Cabriolet and Cabriolet S weigh in at 1500 and 1510kg respectively.
Going all-wheel drive adds around 55kg to the weight of each model.
Other range-wide upgrades include a third-generation PCM3 version of the Porsche Communications Management (PCM) system, comprising a bigger new 6.5-inch touch-screen. It can be optioned with satellite-navigation including a 40GB hard drive, plus voice control and a TV tuner.
Further changes run to larger and more ergonomically user-friendly buttons in the console, and the option of ventilated front seats.
Porsche expects 911s packing PDK to account for about two-thirds of all sales, up from the Tiptronic’s 50 per cent share, with the Carrera S taking slightly more market share than the 3.6 models.
The original 997 series 911 arrived in Australia in October 2004.
It is just the third-generation car to wear the famous set of numbers since the 911 debuted as the 901 (until Peugeot complained about the use of a ‘0’ in the middle) in 1963 – although Porsche fans will rightly point out that continual development created virtually all-new 911s in 1989 (964 series) and 1993 (993). The second-generation 911 was unveiled as the 996 in 1997.
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