Porsche ’s fuel injected flat-six engine family codenamed M97, members of which still power the current 911 Turbo, GT2 and GT3, will be retired later this year when the German automaker replaces it with a new, direct-injection A91 family. The first versions of the new A91 powerplant were unveiled recently in the 2009 Porsche 911 and 911 S
In the standard 911s, the new direct injection engines are good for 20 to 30 hp bumps in output, and the same is expected for the new turbo engines and higher performance but naturally aspirated GT3 model. As well, the new engines should also return better fuel economy and emit less carbon dioxide emissions. As the UK’s Autocar reports, the 3.6-liter versions of the new engines also feature a new bore and stroke ratio, at 97mm and 81.5mm, respectively, compared to the outgoing engine’s 100mm and 76.4mm. This new, more square design should also improve torque production and beef up the torque curve of the new engines.
The Turbo and GT2 models’ engines will also get a pair of turbochargers and intercoolers, with power estimated to easily climb to the 500 horsepower or beyond mark in the Turbo, up from the current 480, and at least 550 (from 530) in the GT2.
The 3.8-liter flat-six in the freshened up 911 GT3 will share internal dimensions with the 911 S, at 102mm of bore and 77.5mm of stroke. As previously, other internal changes will include lighter and stronger parts that allow for higher engine speeds and more strength. Power should swell from the current 415 to about 430 horsepower.
The across-the-board switch to the new engine will allow Porsche to build the new engine family on one production line at its Zuffenhausen, Germany engine plant.
