BY MATHIEU RAUDONIKIS | 14th Jul 2010
This vehicle, matching Volkswagen Group’s super-charged 245kW 3.0-litre V6 petrol engine with a 37kW/300Nm electric motor, provides an option for potential Porsche buyers who feel the need to save the planet without losing too much performance.
But rather than the best of both worlds, our drive of the Cayenne Hybrid shows that while it is good at both fuel economy and performance, it shines at neither.
Instead of the claimed 8.0 litres per 100km combined fuel economy, our short road test of the Cayenne S Hybrid – taking us out of Brisbane to surrounding hills – could muster only an indicated 15L/100km, although it must be noted that the drive included plenty of climbing.
The Cayenne Hybrid should make a better fist of stop-start city driving, where the electric motor will crawl in traffic. Porsche claims the battery has enough power to drive the Cayenne S Hybrid up to 30km at up to 60km/h on the electric motor alone.
The super-charged petrol engine has an idle-stop function that switches it off when the vehicle is stopped with the driver’s foot on the brake. Easing away on light throttle, the Cayenne is propelled by the electric motor, but anything more than a light squeeze on the throttle fires the internal combustion engine to assist.
The Hybrid has an E-boost button in the redesigned console that when pressed, lightens the throttle action and holds the Cayenne on electric power for longer.
We even felt it shifting through the first couple of gears as we crept in traffic, but again it doesn’t take much application of the accelerator to get the petrol engine to kick in.
The petrol engine also kicks in at a standstill if battery power drops below a certain level, because even with the Cayenne stationary, the battery still has to power the power steering, air conditioning, brake booster and other functions of normal driving.
Once underway, the Cayenne S Hybrid delivers strong acceleration with the combined efforts of the petrol and electric power plants urging you on.
The V6 engine is a bit noisy – and it’s not a nice noise like that of Porsche’s flat-six cylinder engines or even its V8s. A harsh racket is an intrusion in this well-appointed cabin where you expect the refinement of a luxury vehicle.
When you get off the power it’s the electric motor’s turn to be noisy as it regenerates power to the 288-volt battery under the floor of the luggage area.
The grinding-like sound is first heard as you press the brake pedal and continues when you release it and continue to coast. This is the motor working in its generator mode, but again the noise is unexpected in a vehicle of this calibre and with a starting price of $159,900.
The Cayenne is much a luxury sports vehicle with a feature packed cabin and a stiff chassis and the S Hybrid carries these traits.
All three of the Cayenne models feature height-adjustable air suspension as standard. The two lower spec vehicles, the entry level V6 and diesel, will ride of steel springs with air as an option.
Porsche’s active anti-roll bar system is standard only on the Turbo and optional on the lower grades.
Even without this clever function, the Cayenne belies its 1995kg (Cayenne V6 manual) to 2240kg (Cayenne S Hybrid) mass to give a truly rewarding driving experience on a mountain road. The new model feels lighter and more agile than its predecessor, with quick steering and flat handling.
The heavier Hybrid wants to push through corners more than the Cayenne S V8, but its dynamics are still exceptional for a large SUV.
An issue when driving the Hybrid in give and take conditions is the sensitivity of the throttle. It picks up quickly in stop-start city traffic, and when on the open road and in the hills, its pick up is sharp when the drivetrain coasts in sailing mode off the throttle and getting back on it snaps back in to action.
This can catch you out when easing back on the gas coming out of a corner. The feeling is reduced by manually holding a lower gear, but that gets away from the fuel saving ideals of the hybrid drivetrain.
Sailing mode is unique to Porsche’s parallel hybrid system which switches off and disconnects the combustion engine when coasting.
The brakes too are sensitive, and their willingness to bite takes a bit of getting used to as well.
This wasn’t evident in either of the V8 Cayennes we drove, including the Turbo with its larger diameter discs. All E2 Cayenne variants have improved brakes over the first generation model, with ceramic composite discs now available as an option on all models for the first time.
None of the niggling gripes of the hybrid apply to the Cayenne S and Cayenne Turbo models. The 4.8-litre petrol V8, both naturally aspirated and turbocharged, is smooth and refined, emitting a pleasant growl when asked to.
Both engines work well with the new engine-speed auto transmission whether left to its own devices in drive or shifted manually.
The 368kW/700Nm Cayenne Turbo is other-worldly when the pedal is pressed, giving sports bike like acceleration and living up to the Porsche crest now rightfully located on the hood rather than on the nose where it was on the earlier model.
It leaves no reason to question the company’s claims of a 4.7 seconds zero-to-100km/h and there’s no need to back off in the curves as the chassis and massive 20-inch low-profile tyres do an excellent job of managing the weight and body roll.
All variants now have idle-stop, making the Cayenne the first production vehicle with an automatic transmission to have this feature.
The system can be switched on or off. With it on, the engine is turns off when the car comes to a stop with the driver’s foot on the brake. If there is any steering input or the transmission shifter is operated as if parking, the engine will not switch off. It is also disabled when the transmission is in sport mode.
When the brake pedal is released the engine starts almost instantly, allowing the driver to move away.
Despite losing its low range transfer case the E2 Cayenne still performs commendably off road. The short demonstration we saw showed that the improved electronic systems, including off road mode traction control, hill descent control and height adjustable suspension, allow the Cayenne to cover steep and rutted terrain with relative ease.
With such great performance from the $147,900 Cayenne S and efficiency of the $104,500 Cayenne Diesel, it’s hard to think of a reason to buy the more expensive Cayenne S Hybrid at $159,900.
Porsche Cars Australia’s Michael Winkler predicts only five to eight per cent of local buyers will opt for the Hybrid, while worldwide, including the US where they don’t get diesel engines, the company is expecting only 15 per cent of total sales.
There are those people who like the warm and fuzzy feeling of driving a hybrid and those who like to be seen driving one. For these buyers the Cayenne S Hybrid’s dash gauges give a constant readout of how much energy they are saving and regenerating, and Porsche has even put a ‘Hybrid’ badge on the front mudguards where other model have no designations.
As the cleanest model in the Porsche range the Hybrid also helps to lower the company fleet emissions tally, but for the Australian buyer it would be difficult to justify on performance or economy alone.
And that’s without considering that with the Hybrid you are left with the spare wheel taking up space in the luggage area as the battery is fitted below the floor where the space-saver resides in the other models.
As Mr Winkler says: “The Cayenne S Hybrid is provides another choice for Porsche buyers.”
Whether it will be a popular choice remains to be seen.