Porsche has boxer fours coming

The 918 RSR two-seat mid-engined coupe blends technology from the 911 GT3 R Hybrid race car with that of the petrol-electric 918 Spyder concept. Photo / Supplied

Porsche has confirmed that it has a four-cylinder boxer engine lined up for the next-generation Boxster and Cayman models - but there is some confusion about its capacity.

Porsche chief executive CEO Matthias Muller last month said a 2.4-litre four-cylinder boxer unit was being developed from an existing flat-six cylinder unit.

He said the four-cylinder was just one of a range of more fuel efficient, less polluting engines under development to help Porsche meet new fleet CO2 emission targets. Both naturally aspirated and turbocharged versions of the 2.4-litre unit were being considered, he said.

But Porsche research and development boss Wolfgang Durheimer talked to reporters at the Detroit motor show of a 2-litre flat-four with turbo technology to ensure performance as well as fuel and emissions savings of up to 12 per cent.

"If you are talking about performance, you need a turbo," he said. The engine is expected to arrive from 2013. It would be built alongside the latest iteration of the flat-six engine family and would offer a PDK dual-clutch automated gearbox, along with an optional six-speed manual transmission.

Durheimer even suggested that future iterations of the 911 may also receive four-cylinder power. "[It] could even be applied to the 911," he said. "We'll stay with the 911 flat-six ... but there are opportunities for the future."

However, a Porsche spokesman later said there are no serious (four-cylinder) plans on the drawing board for now. Durheimer has been with Porsche for 11 years and next month takes over as engineering chief of Bentley Motors, also owned by Porsche parent the Volkswagen Group. The new four-cylinder engine, whatever its final capacity, is likely to first go into the mid-size Cajun SUV and new entry-level sports car based on VW's new MMB platform, which will also underpin the VW Bluesport, tipped for launch in 2013.

The Cajun is due in 2014 and the sports car - which sits below the Boxster - a year or so later.

"We have a model based on the Bluesport, but we are not yet ready to show it," said CEO Muller.

"When we are convinced about the project, we will be ready to show it. However, we do not have to show this car off as a concept to make a decision on its future. We have all the facts and figures we need. The first time you see it, it will be as a production ready car."

Meantime, the first of an upcoming line of higher-performance Porsche models carrying the "R" badge is expected in New Zealand in May/June.

The "R" stands for responsive, refined and racy, says Porsche, and will appear on special versions of the Boxster, 911, Cayenne, Panamera and Cajun. It is also expected on the entry-level model.

The Cayman R will sit above the Cayman S in price and performance, thanks to lightweight components, specific chassis tweaks and an extra 8kW of power, bringing the maximum output of its mid-mounted 3.4-litre direct-injection six-cylinder boxer engine to 243kW/270Nm.

Gearboxes run to either a six-speed manual or six-speed PDK double-clutch. Porsche claims the manual Cayman R sprints from zero to 100km/h in 5 seconds, shaving two tenths of a second off the time achieved in the Cayman S.

The optional PDK unit propels the Cayman R to 100km/h in 4.9 seconds, or 4.7 when the optional Sport Chrono Package with launch control is fitted.

Porsche used the Detroit show to unveil its 918 RSR, a two-seat mid-engined coupe that blends technology in the 911 GT3 R Hybrid race car with the design of the petrol-electric 918 Spyder concept.

The 918 RSR is powered by a revised version of the V8 engine from the RS Spyder race car, tuned to deliver 420kW at 10,300rpm. The electric motors on the two front wheels each contribute 75kW, boosting overall output to 570kW.

The electric motors offer a torque vectoring function with variable torque distribution to the front axle. Porsche says this improves agility and steering response.