The making of a fast SUV

  • Strategic use of hot and cold formed steel make for a very rigid body. Note that the side panel is one piece.
  • On a damp day and on "summer" tyres, the Cayenne made short work of clambering up an intimidating rock face.
  • a closer look at the electromechanical roll stabiliser reveals the pivot motor powered by the orange cabling of the 48 V system. Right: the PSCB's tungsten-carbide coating has a mirror finish that supposedly won't corrode over time.
  • This suspension is almost identical to that found on the Audi Q7.
  • The modular quad-core processing unit uses one processor per suspension or body control system.
  • Porsche's new gearbox design runs the front axle half shaft through the housing.
Date:29 January 2018 Author: Lindsey Schutters Tags:, ,

Porsche’s new Cayenne has some innovative technology underpinning its spicier new driving dynamics. Lindsey Schutters takes a look under the skin.

The new Cayenne is the fastest phone you can drive in. Seriously. Porsche went to the trouble of developing a voice assistant with help from Nuance, so the car can stream Amazon Prime Music. The company developed its own navigation and maps service with market-dependent partners such as Navi and TomTom and you can specify your Cayenne with an embedded SIM. Of course, there’s also online radio streaming on board and compatibility with podcast apps like Stitcher.

But very much unlike a regular mobile phone, any planned future features won’t arrive via over-the-air software updates. You need to choose your features carefully, for that decision dictates which configuration of the modular quad-core processor your vehicle comes with. Oh, and those mid-2018 upgrades are also hardware-based, so wait until those features are released before buying a new Cayenne. You just won’t get them if you don’t.

This flies in the face of current industry trends, spearheaded by the likes of Tesla and Volvo, whereby you can gain new features overnight, assuming of course that your car is connected to your home Wi-Fi network. Volvo XC90 owners with all the Pilot Assist hardware installed, for instance, gained semi-autonomous drive up to 135 km/h – up from the original 35 km/h – in one such OTA update. Even Ford customers with SYNC 3 installed gained basic Apple Carplay and Android Auto powers without needing to visit a dealer.

But this is about the new Cayenne. At the heart of the Porsche system is the modular electronic control unit. There are four separate processors – one for each family of electronic services. When you specify your car – in particular, the driver assistance systems and features – it determines which processors get added to the ECU. This model works well for the economics of car assembly and gives Porsche a lot of wiggle room to evolve the product as technology gets better, but leaves the customer exposed to obsolescence. It’s a problem that Porsche shares with Tesla, where later models of the same car will gain extra features as the underpinning hardware gets more advanced, even within the same model year.

Don’t worry, though. Porsche didn’t go full crazy with the building a drivable smartphone idea. Stuttgart reached out to Cupertino when it wanted to cosy up to a smartphone maker and the iPhone integration runs quite deep. The OneConnect application, for example, uses TouchID for authentication and makes use of 3D Touch shortcuts. There’s also an Apple Watch complication for some of the OneConnect features and the engineers did let slip that TouchID could be used for keyless entry in the future.

Porsche’s user interface is elegant and seems easy enough to master, but the larger question is whether it is in the best interests of the manufacturer to spend all that time and effort of setting up servers and developing software when most customers will simply plug in their iPhone and use Apple’s solution. Google’s Assistant and related services are already an essential part of the modern technological experience, the same with Siri and the related iOS software solutions. These are mature ecosystems built on a foundation of at least a decade of research and development. So let’s rather focus on the things the new Cayenne really excels at.

Something old
Gone is the double wishbone front suspension and, in its place, a new multilink system built with an aluminium sub-frame. Porsche’s engineers have simultaneously shed 65 kg of weight and dramatically improved the driving dynamics while also removing vibration from wheel imbalances. Around back is the vintage multilink set-up, but now forged aluminium links alongside lighter steel links. Rear-wheel steering was the key factor behind the shift to this new configuration.

Well that and the off-shelf design Porsche received through its involvement in the larger Volkswagen group. The new chassis design is almost identical to that of Audi’s reimagined Q7. Granted, that was an evolution of Porsche’s own 911 rear axle. Rear axle steering in this instance, however, is used to help make the SUV more drivable in lower speed situations. The system works only up to about 80 km/h and reduces the turning circle to 11,5 m from the original 12,1m. The craziest thing, though, is that this wheel movement is achieved through the flex of the rubber bushings, as there is no actual steering rack.

Something new
To complement the rear-wheel bias in power delivery (front wheels are powered on-demand), the new Cayenne now comes with mixed tyres. The rubber on the larger new wheels comes in 255/55 and 275/50 for the 19-inch and 285/40 and 315/35 for the 21-inch option. This shift is inspired by Porsche’s experience with sports cars and is said to increase comfort as well.

On stopping duty, however, is a world-first Porsche Surface Coated Brake (PSCB). At its core the new brake disc is still cast iron, but now with a heat-applied tungsten-carbide coating. The new coating is significantly harder than cast iron and offers 30 per cent longer service life. It’s mated to specifically developed pads and the combination is said to also significantly reduce brake dust. You can still specify Porsche’s acclaimed ceramic composite brakes, but this new development offers comparable improvements to stopping at a cheaper price point.

Something borrowed
Dipping into the Q7 parts bin also gains the Cayenne the benefit of excellent electromechanical roll stabilisation. The three-stage planetary gearbox at the heart of the system is driven by an electric motor powered by the 48 V system, allowing for anti-roll bar torsional rigidity adjustments within milliseconds. This design effectively splits the anti-roll bar in two, joined by a pivot motor which will spin the two in opposite directions depending on roll angle. Decoupling the anti-roll bar is then just a matter of allowing the mechanism to freewheel.

Something blue
Weight savings in the body construction were achieved through using more aluminium than ever before alongside boron-alloyed steel. Aluminium use is actually up to 47 per cent, with even greater use forecast should safer cars bring about changes to legislation around body structure. Up to 135 kg was shed in total over the previous generation. Increased use of aluminium also means new production methods, one of which is the six-stage press method to produce the side panel from a single sheet of metal. There is only one manufacturer in the world that could accommodate this request.

In all, Porsche has achieved something quite special with its new Cayenne, a true SUV that is as capable on the road as it is off it. Whether it’s enough to compete with Range Rover’s new Velar and similar SUV offerings reaching our market in 2018 remains to be seen. The only certainty is the Stuttgart-based company’s commitment to engineering some of the finest motorcars on the planet.

One app to rule it all
Porsche’s proprietary OneConnect app does all the things you’d expect from a connected smartphone application. You can set routes that will sync with the car’s navigation system either automagically by connecting your Outlook calendar or in the maps section of the app. There’s also self park, which allows you to line up the car with a tight parking space, hop out and execute the final manoeuvre remotely. In the cabin, you’re greeted by a 12,3-inch display in the centre of the dash and two 7-inch screens behind the steering wheel.

Wings of change
Adding to better braking and general stability is an active rear spoiler. When you take the Cayenne above 160 km/h, the spoiler lifts by 20 mm to increase downforce. If you’ve selected the Sport+ driving mode or drive above 180 km/h, it raises to 40 mm (60 mm if the sunroof is open to compensate for the windscreen). Above 250 km/h, the spoiler drops to just below 40 mm again as the benefits of added downforce are outweighed by the added drag. When stopping from these incredibly high speeds, the spoiler tilts up to create an air brake that can shorten stopping distances by up to two metres.

Latest Issue :

May-June 2022