Video: Porsche 991 Turbo S rear axle steering in action
You already know the 991 Turbo S is the fastest, most technologically advanced 911 Turbo to ever leave the Porsche factory. Boasting an unworldly 560hp, the new S carries over an array of firsts from its 520hp 991 Turbo counterpart, including electrically-assisted power steering, seven-speed PDK transmission (a compulsory option) and, of course, rear axle steering.
This clever technology – first mooted by Porsche engineers as far back as the 993 Turbo era – uses electromechanical actuators to steer the rear wheels by up to 2.8 degrees depending on speed. Below 50 km/h, the system steers the rear wheels in the opposite direction to the front, serving to effectively shorten the car’s wheelbase by 250mm, aiding agility.
At speeds above 80k m/h, the rear wheels are turned parallel to the front, effectively lengthening the wheelbase this time by 500mm, enhancing stability on turn-in.
Perhaps the beauty of rear axle steering is that you can’t physically feel the technology in action (a sentiment echoed to us by Porsche’s first Le Mans-winning stalwart Richard Attwood last month), which got us thinking: can you even see it?
After running the 991 Turbo S on a purpose-built course as part of the 991 v 993 Turbo S face-off in issue 115, we captured this brilliant new technology in action.
To read our full feature on the 991 Turbo S taking on the venerable 993 Turbo S along Cornwall’s Roseland Peninsula, pick up your copy of Total 911 issue 115 in store. Alternatively, purchase online at the Imagine Shop, or download a digital copy via Great Digital Mags.
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