Porsche Cayenne Hybrid 2018 first drive

The news that Porsche has, at the very least, put all its diesel programmes on hold makes this new Cayenne Hybrid a car that's more important than usual.

If you want a Porsche Cayenne but care about taxation and running costs, this is the one you’re going to have to buy. Porsche denies that diesels have been ruled out of all future models, but it does say the entire strategy is "under review". So don’t hold your breath.

You’d have thought Porsche would just transfer the powertrain from the Panamera hybrid straight over; it fits and comes with four-wheel drive as standard. But no, the hybrid powertrains in a Panamera and this Cayenne are related but by no means the same. As we shall see, this brings news both good and bad for this luxury SUV.

For a start, the Cayenne Hybrid doesn’t use quite the same engine as the Panamera Hybrid. While the Panamera has a 2.9-litre turbo V6, the Cayenne has a 3.0-litre unit. So that’s good, right? Actually, not really.

The smaller engine’s reduced capacity is a result of a larger, reinforced crankshaft that shortens the engine’s stroke, and you only do that if you want to put more power through it, such as the 440bhp made in the Panamera S. So there’s clearly a hotter Panamera hybrid on the way. 

The Cayenne has no such need, so is denied the smaller, stronger engine. Still, the 3.0-litre unit can generate 335bhp all by itself, to which a further 134bhp of power is added from the electric motor - and that's, indeed, identical to that used by the Panamera.

Total system power therefore amounts to 469bhp. Which sounds good until you realise that while Porsche is making no official claims for this as-yet-unhomologated car, the hybrid system in the Panamera adds 320kg to the weight of the standard car and there’s no good reason why the same (or similar) will not be true for the Cayenne.

The other difference is that while all Panameras have Porsche PDK dual-clutch gearboxes, all Porsche Cayennes have conventional eight-speed automatics. This might not sound too important in the context of a hybrid, but, as I found out in two days of roaming around South Africa in one, it quite demonstrably is.

I can’t tell you how quick it is but, with substantially more power and torque than the old Cayenne Hybrid, I’d estimate a 0-62mph time of a little over five seconds and a top speed of a little less than 160mph. So quick enough, in other words. It should do around 25 miles on electrical power alone – five fewer than the lighter, lower, more slippery Panamera – and 84mph, rather than 87mph, on electricity alone.