Porsche 911 Carrera 4S (997) MkII ~ 2008-
Visually, the big news was the return of the classic full-width rear reflector between restyled LED rear lamps. Also at the back, the bumper was changed slightly, especially between the exhaust outlets and, as before, the car was 44mm wider across the rear.
At the front were LED daylight driving lamps, while Bi-xenon headlamps became standard and borrowed the Cayenne’s dynamic bending system. Also at the front, the air intakes were restyled. Finally, the door mirrors became slightly larger, to meet upcoming EU regulations.
However, this was more than a mere facelift. The 997 was given an all-new engine with 40 percent fewer components. The two-piece crankcase now had integrated crankshaft bearing housings, which reduced weight and size. Also, there was now no intermediate shaft driving the timing chains.
The stroke of the 3.8-litre engine reduced from 82.8mm to 77.5mm, while the bore went up by 3mm to 102mm. This meant that the capacity reduced by 24cc to exactly 3800cc.
The cylinder heads had a simpler construction, and were now one-piece with integrated camshaft bearings and guide liners for the hydraulic cup tappets. The lubrication system was optimised to improve efficiency. Finally, and most importantly, the engine now used Direct Fuel Injection, or DFI. A new option was the PDK (Porsche-Doppelkupplung, or Porsche double clutch) transmission, which replaced the previous Tiptronic S. This seven-speed transmission gave a choice of automatic or manual changes and was faster and more efficient than Tiptronic.
The four-wheel-drive system came from the 997 Turbo and its electronically controlled PTM (Porsche Traction Management) replaced the previous viscous multiple-plate clutch set-up.