Porsche has patented a new type of variable compression ratio con rod ( I bet you never thought you'd read about Porsche con rods here today!)

Turbos work by compressing the intake charge of air and fuel before ramming it into the combustion chamber under pressure. Because a turbocharger is powered by exhaust gas, and therefore is not always running at peak boost, the amount of fuel/air mix entering the cylinder varies from low volume when the turbo is not spinning to maximum volume when the turbo is running at peak revs. Turbocharged engines must therefore run lower compression ratios, to allow that higher volume at peak boost. This costs them power.

One way to increase the efficiency of a turbocharged engine would be to constantly adjust the compression ratio, giving higher compression off-boost, and reducing the compression as boost pressure rises, to prevent detonation.

One way to increase the efficiency of a turbocharged engine would be to constantly adjust the compression ratio, giving higher compression off-boost, and reducing the compression as boost pressure rises, to prevent detonation. The Porsche system (top) is clever, planting the piston on an eccentric mount that is automatically adjusted by control rods, which swivel the piston up or down on the crankshaft connecting rod depending on oil pressure, thus controlling the compression ratio.

http://www.ferdinandmagazine.com/porsche-patents-variable-compression-ratio-engine-technology