997 vs 991 head-to-head

Few generations of 911 were anticipated quite as much as the 991. Yet, at first glance, the new Porsche does not appear dramatically different from its predecessor in the way the 996 was from the 993, and neither is it the urgent and much delayed updating of the previous model that the 964 represented. The 991 is nevertheless a landmark Porsche. Most observers favour the analogy with the 964, which superficially looked very similar to the 3.2, but under the skin harboured much newer technology – the first planks of an updating process not completed for ten years until the 996. The other significance of the 991 is that it is the model that this year represents the icon on its 50th birthday – an unprecedented anniversary in automotive model history. Here, Total 911 pits the 991 with the previous model 997, to find out just how much Porsche has moved the game on.

Comfort 

Porsche’s main objectives with the cabin of the 991 were to enhance quality and equipment, and to improve refinement. The 991’s greater – if deftly disguised – dimensions are reflected in the cabin where the immediate impression is one of airiness, a spaciousness quite unlike previous 911s, which is reflected in the greater shoulder room. Seats have more fore and aft movement, and the rear of the cabin now offers increased luggage/occasional passenger space. The new chassis allows for a deeper boot at the front, too. The 997’s sports seat becomes standard on the 991S, with the previous Sport Plus variety as an option. These seats are firm yet particularly supportive, with the only criticism being that they might be a little tight for those with larger figures.

With its base 77mm further forward, the angle of the windscreen is also very different from what the 996/997 driver is used to surveying, and those famous 911 wings are now slightly more visible. The standard steering wheel is flatter and wider, too, making it all the better for appreciating the 991’s electrically assisted steering. The dashboard largely retains the successful 997 layout, the main change being the conversion of the warning light fourth dial to a more useful information screen which replicates the display, among other information, of the sat nav screen (where it is more accessible to the driver), and also the cornering G-force readout delivered by the optional Sport Plus Chrono. The central info screen itself is also usefully bigger on the 991.

What is most striking about the new interior is that the long march to improve quality, which began after unprecedented criticism of the 996’s cabin, goes on. There were few complaints about the 997’s insides apart from the tendency of the bolster on the driver’s seat to wear and fray, but with the 991 Porsche has produced a more plush interior with more robust wearing surfaces. Most noticeable is the ‘corporate’ raised centre console housing the gearshift, a development first seen on the Carrera GT and more recently extended to the Cayenne and the Panamera. The handbrake lever has also disappeared, replaced by an electric parking brake. The combination of more space and richer materials has elevated the 911’s cockpit to a distinctly ‘grand touring’ environment rather than that of a mere top flight sports car.

The most consistent criticism of life aboard the 997 was the level of tyre roar transmitted to the cabin. This is lowered on the 991 we tried, which had optional 20-inch Carrera Classic rims, and on 19-inch wheels tyre noise is less intrusive still. If there has been any negative reaction at all to the revised interior, it has been of a certain
‘Panamerisation’, which seems to some be taking the 911 ever further from its ethos as a sports car. Porsche would counter that the 911 was always an upmarket car, and the new interior simply reflects the expectations of buyers in this category in 2012. To this, we could add that with three quarters of Porsche production now comprising Cayenne and Panamera, it is no doubt more cost effective to endow the 911 with the same fittings and trim.

997's interior doesn't look dated by any means…
… while the 991's 'Panamerisation' features that new raised centre console, a marmite feature among enthusiasts.

Performance

Porsche’s main objectives with the 911, besides the normal updating, were increases in performance, fuel economy and reduced emissions. This is a squaring of the circle that Porsche has become past master at. Gone are the days when each new generation of 911 was heavier. Weight is the enemy of performance and fuel consumption, and during planning for the 991 an all-aluminium mock-up was built, which turned out to be heavier. Astute use of both aluminium panels (the skin is 45 per cent aluminium) and magnesium has enabled Porsche to reduce the weight of the PDK Carrera from the 1,455kg of the 997 to 1,415kg for the equivalent 991 model, which is quite an achievement given that 58kg of what Porsche calls ‘safety products’ had to be added to the new version. The 9A1 engine from the 997 has been subject to internal changes mostly related to lightening reciprocating parts and drivetrain components and reducing friction losses. The S retains its 3.8-litre capacity, but unusually the base Carrera reverts to a 3.4 version of the Boxster/Cayman S tuned to yield 350bhp, which Porsche says will deliver both better performance and mpg than the preceding 3.6. It’s an impressive claim, but entirely credible when you realise that the electronically variable oil pump introduced in the 997/2 model is now more sensitive to road/engine speed and lateral forces, ramping up oil pressure (which takes energy) only when it identifies the greater stress of track driving or hard cornering. The same philosophy has resulted in the energy saving electric steering. An energy recovery system now operates through the alternator, collecting kinetic energy (without the GT3 Hybrid’s enormous flywheel) from deceleration, which is fed into the battery. Using the same logic, when the accelerator is floored, power to ancillaries is reduced, enhancing acceleration and lessening the overall demand for fuel. A further intelligent saving is the managed cooling system; the 991’s electronic brain confines coolant to the cylinder head, momentarily shutting out the crank case passages, and accelerating the warming up phase when combustion engines are at their most thirsty.

In terms of acceleration, only a stopwatch can separate the old and new 911, yet it feels faster, perhaps because it’s lighter and stiffer. Porsche’s figures (listed below) illustrate how the 991 Carrera PDK – which was our test car for this comparison
– manages to quietly improve on the attributes of its predecessor in all departments, bar the maximum speed, which stays at 178mph. Power is up by 5bhp, with an additional 3lb ft of torque, and it’s a tenth of a second quicker to 62mph, yet boasts both lower fuel consumption and CO2 emissions.

Where the 991 does impress over the old car, though, is with the interior sound level. The newer car, as mentioned earlier, dispenses with much of the 997’s tyre noise. Instead, the (now standard) sport button is linked to an acoustic tuner, which brings the characteristic flat-six exhaust note into the rear of the cabin – a very clever arrangement that is achieved without making the external exhaust note excessively loud.

*For the full 991 v 997 feature including a definitive verdict, turn to page 18 of Total 911 issue 89 now. To get your copy wherever you are in the world, visit the Imagine Shop at www.imagineshop.co.uk/magazines/total911.html, or download a digital edition for all platforms via the fabulous new GreatDigitalMags.com website.


More from Total 911


Comments (0)