Milestones Of The Porsche 911’s Flat-6 : History Alley

The Porsche 911 has always made use of an impressive flat-6 engine hanging back behind the rear axle – that is, if you count the entry-level 912 from 1965-69 as something un-911. But the 1970s saw the introduction of a different spin on the classic flat-6 when it gained a turbosupercharger, and the much-beloved 911 has embraced that addendum ever since.

The decision for Porsche to engineer a flat-6 turbo for the 911 was made due largely to the lack of space to accommodate anything bigger than the existing, compact powerplant. The first change since the Porsche turbo’s 1975 introduction was an intercooler to cool the intake charge and help mitigate the effects of time needed for turbo spool-up.

Several generations later came the Porsche 911 Turbo 3.3 from the 1990s, whose release untimely coincided with stricter emission controls. Porsche’s solution was to seek help from a supplier in developing a metal – rather than ceramic – substrate, allowing it to get up to operating temperature much more quickly.

Perhaps the biggest leap for the Porsche engine yet came in 1995, when the flat-6 turbo got two smaller turbochargers in the Porsche 993 Turbo in place of the single, slower-spooling turbo. Because the two smaller units each reach their effective RPM more quickly due to increased inertia, this helped greatly with low-end torque.

Finally, for the 996 generation in 1999, Porsche ditched their much loved air-cooled engine and made use of water-cooling. This water-cooled engine also got a variable valve-timing system in the 911 Turbo, which changes valve lift substantially with engine RPM to maximize efficiency. Seven years later, the 997 gained a Variable Turbine Geomoetry system, even further reducing the time of spool-up at lower RPMs.

The latest major milestone for the Porsche flat-6 turbo was the inclusion of direct injection in 2009, which has a greater effect on intake charge cooling and allows for more compression. With this addition, even with a displacement of only 3.8 liters, this flat-6 turbo pumps out a very healthy 560 HP.

It is an ever-evolving powerplant and, regardless of how far today’s Porsche 911 Turbo motor has gotten from its original design, an integral feature of this iconic car.

Aaron Birch is an automotive enthusiast and writer/filmmaker from Detroit, MI. As a rule, he only buys cars older than himself.

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