997.1 vs 997.2 Mechanicals
Direct injection and PDK double-clutch gearbox.
Lets talk mechanical differences between the Mk 1 and Mk 2 997 cars first. The 911 Carrera, Carrera 4, Carrera S, Carrera 4S Coupe and Cabriolet bodies all had Mk. 1 variants, as did the Targa 4 and Targa 4S. The 997 Mk. 1 non-S cars had a 3.4 liter flat six with 321 bhp and 273 ft lbs of torque. The S models got a bored-out, 3.8-litre version of the flat-six, with more power and torque. The Turbo models got a 3.6 liter engine with 473 bhp and 460 ft lbs of torque. All models above had a 6-speed manual transmission with a 5-speed Tiptronic automatic transmission as optional. All of these engines got port-injection, which is important compared to the 997.2 models. Mechanically, the 997.2 cars were all about the engine and transmission changes. European emissions laws meant Porsche had to make some changes, in particular by driving for higher power efficiency by means of direct fuel injection.
The 997.2 cars all got this new direct injection engines. The cooling effect from spraying gasoline directly into combustion chambers allows for higher compression ratios (both the 997.2 3.6 and 3.8 engines now run 12.5:1 compression) and the result is more power and torque. The 997.2 3.6-liter non-S engine produces 339 bhp, 20hp more than the 997.1 lump, while the 997.2 3.8-liter "S" engine is good for 380 bhp, up 30hp vs the 997.1 version.
While there were other modifications to the boxer engines, they are relatively minor. The 997.2 engines got revised bore and stroke dimensions, lighter engine construction and reduced friction of moving parts. In the end, the new engines return not only more power but also considerably lower fuel consumption and carbon-dioxide emission. The other big technical change with the 997.2 cars was the introduction of a dual clutch gearbox to replace the automatic. Another way to enhance performance while reducing fuel and emission is to work on the gearbox and that is what Porsche did. After a long delay, ZF finally completed a 7-speed double-clutch gearbox for Porsche.
The 7-speed PDK in the 997.2 cars was a big advancement not only compare to the 5-speed Tiptronic automatic transmission it replaced, but also to the standard 6-speed manual gearbox still serving the new 911. Fast and seamless gearshifts cut 0-60 mph by a further 0.2 seconds across the range. However, this improvement is not brought by the additional gear, because 7th is actually an overdrive to enhance fuel economy in highway cruising.
An optional "Sport Chrono Plus" package was also introduced in the 997.2 cars. It adds a digital and analogue timer to the dash top for hardcore drivers to measure lap time on racing circuit. Another important function it brings is a launch control, which could cut another 0.2 seconds from 0-60 mph. Besides, the package provides a Sport mode button to set the sharpest throttle response, heaviest steering, fastest PDK gearchange, stiffest adaptive damping and higher threshold for the PSM stability management system. Relatively light other changes were made to the chassis. The springs, dampers and PASM adaptive damping have been mildly retuned. Bigger brakes (330mm all round) are adopted on the Carrera.
On the road, the biggest difference between the 997.1 and 997.2 cars is the engine and gearbox. The engines feel like they pull harder in the midrange, without any drop-off all the way to the redline. The number don't reflect how much more enjoyable the direct injection engines are. The dual-clutch transmission is also a revelation compared to the 997.1 automatic, with smoother and faster shifts every single time.
Best 997 Model to Buy
If you have a cool million dollars we highly recommend you stop reading this and run out to buy the GT3 RS 4.0. The lighter, harder, "regular" GT3 RS is widely regarded as one of the finest road-going driver’s cars of all time, especially in ultra-rare and chillingly expensive 4.0-litre guise. For many, this is peak Porsche – the perfect modern balance of performance and feedback. Prices are high now, as high as the equivalent 991 successor, and unlikely to head anywhere but north. If that is a stretch, then the 997.2 GT3 is one special sportscar and also up there as one of the greatest sports cars ever made. For regular folk, the 997 GTS is a sure bet. It has the relative understatement of a Carrera 4 bodyshell, blessed with more power and torque and one of Porsche’s finest manual shifters around. The wider rear tracks and stiffer suspension setting also allow the GTS to corner flatter, sharper and more neutral than Carrera S. Its handling and ride quality bridges the gap between Carrera S and GT3. To many people, the GTS is probably the best balanced package, satisfying the need for excitement and comfort simultaneously. Where prices for the full-blown GT cars have gone stratospheric in recent years, the GTS remains an affordable option.