Porsche: Cayenne goes on diet

Porsche's Cayenne hybrid is the most frugal SUV in its class despite V8 grunt. Photo / Supplied

Porsche unveiled the new-generation Cayenne SUV at the Geneva Motor Show with a hybrid car as its headliner.

But the performance-focused brand hasn't gone mad; this hybrid relies on the strong torque of an electric motor to deliver V8 grunt alongside six-cylinder thirst, much as Lexus does.

The format matches a 245kW, 3.0-litre supercharged V6 with a 34kW electric motor slotted between it and the gearbox, using one or both according to conditions. Together the pair deliver a muscular 279kW and 580Nm - at only 1000rpm.

Drivers can use the electric motor alone for silent, emission-free running at round-town speeds. But it will cut out at speeds of up to 156km/h if no further power boost is required - during high-speed cruising, when reducing the drag caused by the petrol engine is more important than any drive it may supply.

Porsche says the hybrid will deliver 8.2l/100km economy. But fuel use is down across the range, thanks to stop-start and an eight-speed Tiptronic auto transmission that keeps the Cayenne in its sweet spot whenever possible.

That means even the normally aspirated, 294kW 4.8-litre V8 uses 23 per cent less fuel than before - at 10.5l/100km - while its 368kW biturbo V8 sibling's tally is 11.5.

It also means the V6 diesel remains the most frugal car in the range, its 20 per cent improvement taking claimed thirst to 7.4; not bad for an SUV.

Porsche says it's put the cars on a strict diet, slashing heft by 180kg for the S, despite a larger body that's 48mm longer, with wheelbase extended 40mm. That weight loss comes via the less complicated transmission and more use of aluminium.

New Zealand will get the hybrid when the first cars go on sale in July in Cayenne S, S hybrid and Turbo formats with the price-leading V6 petrol and diesel cars to follow.