Diesel is a dirty word at Porsche, but can petrol-electric power fill its shoes in the new Cayenne?
What we liked:
• Pace off the line
• Cabin design
Not so much:
• Feels heavy
• Jerky brakes
• Unforgiving ride
Offering a large SUV without a diesel engine would have been unthinkable even two years ago but, in the wake of Dieselgate, that’s exactly the position Porsche finds itself in 2018. One is coming, the famous sports car maker claims, but it can’t (or won’t) tell us when. Until then, those who would have bought a diesel-powered version of the new Cayenne have been asked to consider the plug-in E-Hybrid instead. On paper, it seems a fair trade. If you can live with having to physically plug it in regularly, Porsche says the E-Hybrid is not only fast, but can average a miserly 3.2L/100km with the added bonus of a 44km pure-electric range. Read on to find out if it’s a real diesel substitute.
Solid starting point
We’re already big fans of Porsche’s third-generation Cayenne, which is one of the finest luxury SUVs out there and arrives in Australia by mid-2018, but so far we’ve only driven petrol versions.
That’s not very useful because historically the majority of all Cayenne buyers Down Under have bought the diesel.
It’s easy to see why. Not only was the previous entry-level 3.0-litre V6 turbo-diesel surprisingly quick, it was frugal and could cover more than 1200km on a single tank.
It should have been a no-brainer then to replace it, but the backlash against diesels in Europe following Volkswagen’s emissions scandal — in which the Cayenne Diesel was implicated — has seen Porsche’s enthusiasm for diesel vaporise.
A new Cayenne Diesel is coming, but unhelpfully the Porsche execs at the global launch of the Cayenne E-Hybrid couldn’t or wouldn’t say when.
For now, the famous German sports car maker hopes the 60 per cent of Cayenne buyers who would have bought the diesel will buy the plug-in E-Hybrid instead.
The sporty SUV, of course, isn’t the first recipient of the car-maker’s next-generation electrified powertrain. It was the job of the Panamera 4 E-Hybrid to debut the efficient petrol powertrain early last year.
Before that, a similar but less powerful powertrain was introduced under the bonnet of the Audi Q7 – an SUV the Cayenne shares its platform and much of its new tech with.
Under the bonnet
In the Cayenne, Porsche has once again combined a 250kW 3.0-litre turbo-petrol V6 with a 100kW front-mounted electric motor.
Feeding said motor electrical current is a 14.1kWh lithium-ion battery that’s mounted near the rear axle, with its aluminium magnesium alloy case acting as a structural component.
Combined, the system generates 340kW/700Nm. That’s impressive because the E-Hybrid produces both more power and torque than the substantially more expensive Cayenne S (324kW/550Nm).
Unfortunately, the hybrid’s extra punch comes with a hefty weight penalty of around 275kg, meaning it hits 100km/h in five seconds dead – just 0.1sec slower than the Cayenne S.
To help combat the 2295kg mass the E-Hybrid hauls around, the plug-in Cayenne gets both active rear-steer and an electro-mechanical active anti-roll bar powered by supercapacitors instead of Audi’s trick but heavier 48-volt system.
Finally, there’s a three-chamber air suspension and adaptive dampers that work in cooperation with the hybrid’s new four driving modes.
The last Cayenne hybrid couldn’t be optioned with a tow hook – a mistake Porsche wasn’t prepared to make with the new model, which can now tug up to 3500kg.
Unusually, the most efficient Cayenne also comes with the option of both Porsche’s powerful 10-piston calliper brakes and its carbon-ceramic brake package that has been specially designed for track use.
This incongruous combination hints at the performance on tap that instantly makes itself known within the first few metres of your drive.
Behind the wheel
Accelerate away from the line and it’s the electric motor that dominates. Able to deliver its full 400Nm from zero revs, the thrust is impressive as it ‘torque fills’ the momentary gap before the V6 turbo mill gets into its stride.
It’s the same for overtaking. Punch the throttle and the response is, well, electric.
Better still, behind the wheel as you launch yourself to the horizon, all you hear is the sound of a sweet hard-working petrol V6, instead of a gruff, gravelly diesel.
Combined with an eight-speed automatic, gearchanges are almost imperceptible in all but the sportiest settings. The transmission is so intuitive, in fact, there’s very little need to reach for the paddles even in its ‘Sport’ and ‘Sport+’ driving modes.
Unless you’re pressing on, in most circumstances you’ll be better off in the hybrid mode, which uses the sat-nav to calculate when best to rely on the electric motor and when to start burning the fossil fuel.
In pure-electric mode, Porsche says it’s not only possible to cover 44km without the petrol power kicking in, on battery power alone the Cayenne can crack a highly illegal 135km/h.
With the average commute less than 35km, Porsche claims that from Monday to Friday some owners will not burn a single millilitre of fuel.
That might be true in Germany where fast-chargers are widespread, but less likely Down Under as most of us will have to rely on home charging that takes seven to eight hours using a domestic socket.
Install a fast-charger at home or work and, if you tick the box for an on-board 7.2kW charger, this falls to two or three hours.
Since most Cayennes seem to spend their life in the urban jungle, it’s appropriate, in town, the Porsche has added four-wheel steering that lends the large SUV nimbleness you wouldn’t believe.
The steering is surprisingly quick too, helping provide the illusion the Cayenne is a much smaller, lighter car.
That sensation doesn’t last when you do eventually escape the city and find a tight and twisty stretch of road.
Despite the inclusion of the active roll-stabilisation in its dynamic armoury, body roll hasn’t quite been eradicated.
Tip into a corner and, initially, you might even think it’s not working, but concentrate and you’ll become aware how quickly the Porsche SUV’s body settles.
This, in turn, helps the Cayenne change direction quicker, but it’s no sports car in drag.
Interestingly, work the Cayenne E-Hybrid system hard and it, eventually, runs out of charge. It’s then possible to delve into the sub-menus and select the E-Charge mode that uses the combustion engine to charge the batteries.
Even when depleted and showing no charge, the hybrid powertrain still frequently slips the SUV into pure-electric mode boosting fuel economy.
Speaking of which, it’s almost impossible to judge what fuel consumption you’ll actually return from the plug-in Porsche as it depends on usage and how much charge is available.
After a day behind the wheel of varied driving, the trip computer indicated we were returning around 8L/100km – a similar figure to what the old Diesel would return.
It’s on highways where we’d expect the old-tech oil-burner to triumph over the new plug-in tech, but if you live in the city the E-Hybrid could be a better match.
Pros and cons
Unfortunately, opt for the E-Hybrid and you’ll have to live with a choppy ride.
Despite boasting a fancy three-chamber system that’s combined with adaptive dampers at lower speeds, the Cayenne was far too easily unsettled and upset by a road’s imperfections.
It didn’t help that our car rode on 21-inch rims (an even bigger 22-inch option is available) – we’d be sorely tempted to downsize to at least 20s.
The next gripe concerns smoothly modulating the brake pedal, typically when entering a town.
The pedal responds in an inconsistent manner, with too much braking at the top of the pedal and a weird pulsating brake re-gen as you brake further.
It’s worth noting that the cars we drove were pre-production but we’ve noticed similar issues with the E-Hybrid-powered Panamera.
We’re not questioning the actual performance of the brakes but wish it was easier to brake more smoothly around town and at slow speed.
Like the rest of the latest Cayenne line-up, the E-Hybrid comes with a cabin among the best in its class for fit finish and the intuitive way it works.
New for the plug-in Cayenne but expected to be introduced to other models in the range is the addition of a head-up display, massage seats and a heated windscreen.
Priced at $135,600 in Australia when it arrives in the third quarter of 2018, the Cayenne E-Hybrid is $9900 less expensive than the model it replaces.
That makes it over $6000 more expensive than the Mercedes GLE 500e, but almost $5000 cheaper than the Audi Q7 e-tron and $10K less than the plug-in BMW X5.
Encouragingly, Porsche hasn’t skimped on the kit, with the only serious omissions being that the E-Hybrid misses out on air suspension as standard and a space-saver spare wheel isn’t even an option.
Undoubtedly, the more athletic non-hybrid Cayenne S remains our choice for its superior driving dynamics, but for those who desire a little more efficiency the plug-in E-Hybrid has much going for it.
In fact, we’d willing to wager that many will actually prefer life with the plug-in and choose it over the diesel — if it ever arrives.
How much is the Porsche Cayenne E-Hybrid?
- Price: $135,600 (plus on-road costs)
- On sale: September 2018
- Engine: 3.0-litre twin-turbo petrol V6 and 100kW electric motor
- Total outputs: 340kW/700Nm
- Transmission: Eight-speed automatic
- Fuel: 3.2L/100km
- CO2: 72g/km
- Safety rating: N/A