PORSCHE INDEX
996 TURBO
The original usable supercar and an exceptional GT, the 996 Turbo remains good value today – providing you buy the right example. Total 911 presents all you need to know
Written by Kieron Fennelly
HISTORY & TECH
The renown of the Porsche Turbo extended well beyond the realm of 911 fans, long before the end of the air-cooled cars. This synonym for wild performance, so redolent of the 1970s, was an image that Porsche had been trying to change since 1984. The stillborn 965 Turbo was an attempt to make a high-spec 4x4, a kind of lesser 959. With the 993 Turbo in 1995, Porsche went much further down the route of creating a sophisticated, range-topping 911 GT with twinturbocharging and all-wheel-drive. The advent of water-cooling and the first new 911 chassis since 1963 enabled Porsche to design the 996 Turbo from the ground up. No longer would engineers have to shoehorn turbochargers, intercoolers and air-conditioning into a shell that was never conceived for them in the first place.
The heart of any 911 is the flat six. The 996 Turbo used a different engine from the Carrera. To justify the considerable development costs of the dry sump ‘Mezger’ (designed in fact by Herbert Ampferer) for the competition-orientated 996 GT3, this engine was also used for the Turbo. Here it could be detuned slightly because additional power would come from the forced induction of the twin K17 turbochargers.
The 11.7:1 compression ratio of the GT3 version was reduced to 9.4:1, which was still impressively high for a blown engine, and the GT3’s titanium conrods were replaced by forged-steel items. Power output was 420bhp at 6,000rpm, with peak torque between 2,700 and 4,600rpm. The introduction of VarioCam Plus helped to improve mpg, but also smoothed the rise in the torque curve which, as ever, bent upwards emphatically at 2,500rpm as the effect on engine breathing of the twin K17s was felt. The 996 was the first Turbo to offer automatic transmission – a five-speed unit from Mercedes-Benz – and optional carbon ceramic brakes.