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Active suspension isn't a new concept – car brands have been experimenting with the idea for decades, using hydropneumatics, air suspension and road-scanning technology to isolate bumps and increase comfort. However, after our first drive of the new Audi S8 limousine, we think Ingolstadt has really cracked it with the super-limo's as-standard 'Predictive Active Suspension.'
Based on an air-suspension set-up, PAS has familiar air-sprung tricks up its sleeve, including a quick 50mm ride-height increase when you grab the door handle, minimising chances of celebrities making undignified arrivals or getaways from red-carpet events.
But it also uses an electromechanical actuator on each suspension arm, with all four controlled by a central computer. This, in turn, is fed information from a camera embedded in the windscreen that keeps an eye on road conditions ahead.
Check out our Audi S8 review
The idea is to minimise body roll and therefore subject occupants to lower g-forces, keeping them almost in an artificial equilibrium. Given the kind of well-heeled folk who'll sit in the back of this brawny V8 limousine, comfort and the elimination of jarring external forces is a top priority – Audi has even upgraded the normal Comfort setting in the Drive Select controller to Comfort+ to stress its extra stress-reducing abilities.
Most notable is how PAS reacts to speed bumps; the ride height swiftly raises by 50mm when the camera system 'sees' one coming. The increase in ride height allows each suspension chamber to compress while minimising the effects of the bump for those inside, almost like it's zapped large lane-spanning speed bumps with a shrink ray. It's not infallible, though, as the camera needs a set distance to see the speed bump in the first place.
Braking and acceleration forces are also counteracted and, between speeds of 50 and 80mph, the S8 will lean into bends by three degrees like a Pendolino train.
It's not all about comfort: go full sporty in Dynamic mode and PAS halves the maximum roll angle of a normal A8 (five degrees down to 2.5) with a focus on the front axle under hard cornering. That, along with the standard rear-wheel steering, means your five metre-long limo steers like something much smaller.
How it works
Stand and deliver
Give the door handle a yank and the S8 rises to attention by 50mm for easier entry and exit
Lean on me
At a cruise, the system tilts into corners by up to three degrees
On its toes
The S8's party piece: raising the ride height (again by 50mm) allows big heavy limo to tip-toe over speed bumps
Predictive Active Suspension: does it work?
Definitely. The road scanning works best when you're not tailgating, and the tilt function can feel unnatural at first, but Audi has managed to bring to market a clever suspension system capable of literally defying the laws of physics, all in the name of keeping its occupants comfortable. Quite the feat of engineering.
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