The variable turbine geometry of the twin water-cooled exhaust gas turbochargers goes a long way to resolving the conflict of aims of normal turbochargers. With this technology, the gas flow from the engine is channelled onto the turbines via electronically adjustable guide vanes. By changing the vane angle, the system can replicate the geometry in all types of turbo, large or small. And thus achieve the optimum gas-flow characteristics. The guide vanes are controlled by the engine management system.
This results in a high turbine speed – and therefore greater boost pressure – even at low engine rpm. With more air available, the combustion is increased, yielding better power and torque. The torque curve reaches its maximum level much sooner – and stays there. Variable turbine geometry also improves the response of the turbo engine with dynamic boost pressure development.
When the boost pressure reaches its maximum value, the guide vanes are opened further. By varying the vane angle, it is possible to achieve the required boost pressure over the entire engine speed range. So excess pressure valves are no longer required.
The fuel economy that is achieved despite the high power output is impressive. Simply efficient, just as it should be with a turbo. A 911 Turbo to be precise.
© 2014 Porsche Cars Great Britain Ltd. Legal notice.
* The latest Porsche models are designed to operate on fuels with an ethanol content of up to 10%. Data determined for standard specification and in the NEDC (New European Driving Cycle) in accordance with the Euro 5 and Euro 6 (715/2007/EC and 692/2008/EC) measurement method. The figures do not refer to an individual vehicle nor do they constitute part of the offer. They are intended solely as a means of comparing different types of vehicle. You can obtain further information about individual vehicles from your Porsche Centre.
Consumption figures were obtained on the basis of standard equipment. Special equipment may affect consumption and performance.