The new 640PS Turbo GT is the fastest Cayenne ever

When Cayenne launched back in 2003 it was clear to see Porsche wanted to strike a balance with the car’s image between performance machine and off-roader. Now it is more apparent than ever that the Cayenne is a road car first and foremost, as the Cayenne Turbo GT eclipses the legendary V10-powered Carrera GT for power, torque and performance.

Under the bonnet lies a 4.0-litre twin-turbo V8 with a whopping 640PS (471kW) and 850Nm (629lb ft) of torque, increases of 90PS and 80Nm respectively over the standard Cayenne Turbo. The 0-62mph sprint is over in a silly 3.3 seconds, a drop of 0.6 seconds, and the top speed is 186mph, 8mph more. One hundred and eighty six miles per hour in a Cayenne. The Turbo GT will also manage 20mpg, but few will ever do an economy run in one of these…

Available in the coupe bodystyle only, the Turbo GT isn’t just about outright power, which brings us to its Nürburgring lap time – because how could you launch the fastest Cayenne ever without taking it to the ‘Ring? Porsche test driver Lars Kern, the same man who’s piloted the GT3, GT3 RS and GT2 RS to numerous records, took the Turbo GT around the Green Hell in a scarcely believable 7 minutes 38.9 seconds.

The ride height has been dropped by 17mm, while the car’s various control systems, the power steering and rear-wheel-steer have been overhauled to match the increased performance. Porsche gives the example of the three-chamber air suspension which is now 15 per cent more rigid. The Porsche Dynamic Chassis Control roll stabilisation system has been tweaked to go with additional tyre grip and sharper turn in, while the torque vectoring system now allows for higher locking ratios.

Additional grip comes from specially developed Pirelli P Zero Corsa tyres, and paired to those are front wheels that are an inch wider while the negative camber has been increased by 0.45 degrees. The brakes have been tweaked to reduce fade and unsprung weight and improve performance, says Porsche, but exactly how they differ from the Cayenne Turbo’s brakes remains unclear for now.

As for the engine, that monstrous twin-turbocharged 4.0-litre V8, the extra power has been matched to higher-strength crankshaft, connecting rods, pistons, timing chain and torsional vibration dampers. The eight-speed automatic gearbox and all-wheel-drive system have all been modified, while there’s an additional water cooler for the gearbox transfer case. Those central exhaust pipes you see, the visible elements of the titanium system, are unique to the Turbo GT, and there’s no central silencer… Delightful.

The body has been given a number of modifications, from a new bumper with larger intakes and chunky rear wing (25mm larger than standard), and there’s a carbon roof, black wheel-arch extensions and ‘Neodyme’ wheels.

On the inside there’s Alcantara everywhere an a handful of Turbo GT specific changes, like the 12 o’clock marker on the steering wheel, but the big news is a new generation of Porsche infotainment system, which brings with it more speed and a new user interface.

The price? A hefty £143,910 with first deliveries in the autumn. How far the Cayenne has come.