Porsche four-cylinder Boxster, Cayman coming

Although the new engine won't debut until the two-seaters are in their next generations, Porsche CEO, Matthias Müller, told Germany's Auto Motor und Sport magazine the models would follow the Porsche 919 Hybrid race car's footsteps and continue the downsizing trend.

The racecar uses a four-cylinder turbocharged petrol engine, however it adopts a unique 'V' design whereas Muller insists the new road car engine will use Porsche's trademark flat 'boxer' layout.  "We will continue with the downsizing strategy and develop a new four-cylinder boxer engine which will see service in the next-generation Boxster and Cayman," said Müller.

The engine is being conceived in an effort to reduce the average CO2 emissions of Porsche vehicles, according to Müller. "We will not separate ourselves from efforts to reduce CO2," he said. However, hybrid versions of the Cayenne SUV and Panamera are still expected to remain the German marque's most efficient vehicles.

Normally a smaller engine would indicate a smaller price tag however this isn't likely to be the case with the new Porsches as Muller says the new power plant could produce "up to 395hp," or 295kW in our currency. That's significantly more than even the recently revealed GTS variants of both the Boxster and Cayman, which produce 243kW and 250kW respectively.

The four-pot is expected to use direct and in-direct fuel injection, plus turbocharging technologies to cut emissions while improving power and efficiency over the outgoing 2.7 and 3.4-litre naturally flat six engines used by the current Boxster and Cayman.

It is understood that the new four-cylinder boxer will be used uniquely by Porsche and not shared across the VW Group's vast brand portfolio. Because of the Porsche twins' unique mid-engine layout and specific packaging requirements the engine couldn't be used by other manufacturers, nor would it be used in the Audi Q5-based Macan SUV.

However, if Audi commits to building a sub-R8 mid-engine sports car then the engine and chassis technology would likely be shared between the two brands. The new four-cylinder sports cars from Stuttgart aren't due to be released until the end of this decade.