With modern engines shrinking, and turbos being added, to accommodate emissions regulations and the increasing cost of fuel this isn't a massive surprise. After all, Porsche do have history with 4 cylinder engines. They've been seen in the 356, 550, 912, 914, 924, 944 and 968 - some flat-4, some inline 4 and some turbocharged.
The last Porsche 4-cylinder engine was housed in the 968 in 1995. It was a 3 litre, inline 4 with twin cams and produced 240bhp.
The new 4-cylinder is expected to be all-aluminium and based on the 3.8 litre flat-6 that's found in the Carrera S, but with 2 cylinders removed to bring it down to the classic Porsche 2.5 litre capacity.
Power is expected to be in the region of 350bhp with a limit of 7500rpm. The 7-speed PDK and a 6-speed manual are the most likely gearboxes.
The new 2.5 litre flat-4 will at first be available in the Cayman and Boxster, probably replacing the entry level 2.7 litre flat-6.
But it's the potential for the engine to appear in a new 'baby' Boxster that most excites. Porsches are all well and good but with a prices starting at £37,000 they are outside the reach of most people. An entry level car would bring Porsche ownership closer to many - and it's something Porsche haven't done since the 944, which finished production in 1991.
With closer integration into the Volkswagen Group, Porsche have access to the mid-engined BlueSport concept, revealed by VW in 2009, which could shorten development time of an all new entry level Porsche.
