2007 Porsche 911 Turbo

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Equipped with the newly updated and optional 5-speed Tiptronic S automatic transmission, the all-wheel-drive 911 Turbo will accelerate from a standing start to 60 mph in only 3.4 seconds. This is 0.3 seconds quicker than a 911 Turbo equipped with the standard 6-speed manual transmission. The impressive performance is due to close integration of the variable turbine geometry (VTG) system, the updated Tiptronic S transmission, and the new electronically controlled all-wheel-drive system.

Porsche's variable turbine geometry (VTG) setup on the 2007 911 Turbo was developed in close cooperation with Borg Warner Turbo Systems, and is based on technology which has been widely and successfully applied to diesel engines since the early 1990s. It is nearly identical in concept to other turbo manufacturers' variable nozzle/geometry compressors, including a system that was briefly used on a series gasoline production engine in the late 1980s. This application encountered difficulties due to high operating temperatures---a problem not easily solved with contemporary materials---and production was stopped after a limited run.

After nearly two decades, aerospace-grade materials have allowed the progression of variable-geometry turbo technology to the point that it can now reliably operate in the higher-temperature environment of turbocharged gasoline engines. Porsche's version of variable turbine geometry in the 2007 911 Turbo incorporates these latest material applications, plus a sophisticated control algorithm. The combination produces the advantages of both small and large turbochargers, generating a much wider plateau of torque and providing quicker response compared to the previous generation 911 Turbo, while providing the reliability of fixed-vane turbochargers.

Porsche 911 Turbo: Review (2/2)