Audi A8


Debut: 2017
Maker: Audi
Predecessor: A8 (2010)



 Published on 7 Jan 2018
All rights reserved. 


Claimed to be the world's most advanced car, can it beat Mercedes S-class?


Audi’s top luxury line started in 1988 with V8 (yes, the car was really called “V8”), evolved through 3 generations of A8 until today. The A8 was originally famous for pioneering aluminum spaceframe chassis for mass production. However, that did not earn it more sales. Throughout the years, the A8 failed to rock Mercedes S-class from the domination of F-segment limousines. In fact, it also failed to match BMW 7-Series and usually Lexus LS as well on the global market. What went wrong was hard to explain. The A8 used to be known for avant-garde styling and technology, but somehow not many people saw it as the symbol of luxury. Perhaps the customers in this segment are generally older, more conservative and usually sit at the rear, Audi started shifting the priorities since last generation. In the new 4th generation car, you can see it evolves further to that direction.

The styling of the new car is rather conservative, more so than any of its main rivals. Yes, its hexagonal grille gets wider and more angular, but you won’t say it radical, just like you won’t describe the ever larger grille of Rolls-Royce a progress. The combination of a flat bonnet and an upright nose makes the front look bulky, more like the Q7 SUV than a limousine – yes, it does ride on the Q7’s MLB-Evo platform, but that is not an excuse for the bulky look. The general profile of the car is rather dull and characterless, lacking the sculpted aesthetic of Mercedes S-class. Audi said the 2014 Prologue luxury coupe concept was used as its inspiration, but sadly I found none of its aesthetic is carried over. Don't get me wrong, this is by no means an ugly car, but it just fails to stand out or move the design trend forward.



The nose looks bulky like Q7, with which it shares platform.


The new car is marginally larger than its predecessor. In standard form it is 5172mm long (+37mm), 1945mm wide (-4mm), 1473mm tall (+13mm), while its 2998mm wheelbase grows by barely 6mm. Long wheelbase model, or A8 L, adds 130mm to both the car's length and wheelbase.

In terms of technology, this car is claimed to eclipse Mercedes S-class and BMW 7-Series to be the world's most advanced mass production car. Its long list of technology starts from a multi-material spaceframe chassis that consists of aluminum, magnesium and carbon-fiber reinforced plastics (see illustration below). The majority of the body-and-white, or 58% by weight, is still aluminum in various forms, i.e. stamped, extrusion and casting, but the places subjected to the most severe side impact, i.e. side rails, A and B-pillars, are now made of ultra-high strength steel, which is stronger than aluminum in equivalent size. Meanwhile, the wall separating between passenger cell and boot is made of CFRP, while the front suspension tower brace is made of magnesium. The whole structure is 24 percent stronger torsionally. On the downside, its weight is increased by 51kg, something Audi thought worthwhile as its priority is adding refinement. You can't help feeling disappointed that the new A8 is now 200 kg heavier than BMW 7-Series. Ironically, now the BMW employs even more exotic materials, especially carbon-fiber.



Multi-material chassis replaces ASF, gains rigidity but also weight.


As before, all suspensions are aluminum 5-link setup and mounted on subframe. They are served with adaptive air springs and dampers, but the headline has to be the optional “AI active suspension”. In that case, each corner is served with an electric motor, which can apply up to 811 lbft of torque to the suspension through a coupling rod, raising or lowering the suspension rapidly to deal with bumps or resist body roll. Moreover, in case a side collision is anticipated by the intelligent impact detection system, it can jack up the suspension of that side so that the strongest section of the body (i.e. the sill) is positioned optimally against the impact. The electric motor at each corner is supplied by the car's 48V electrical system, which is pioneered by SQ7.

The active suspension needs better road-reading. This is made possible by using a new laser scanner (mounted at the front bumper) in conjunction with long-range radar and cameras. These hardware also allow the A8 to be the world's first production car capable of Level 3 autonomous driving under some conditions without needing the driver to keep monitoring. In traffic jam, if the driver activates the autonomous driving function, the car will follow the traffic, applying accelerator, brake and steering automatically. However, it is not yet developed to be fool-proof at higher speeds, so above 60km/h (37mph) it will give control back to the driver. If he fails to react, the car will brake to stop.



AI active suspension uses electric motor to raise and lower each suspension.


The 48V electrical system is supplied by a Li-ion battery mounted under the boot. It is charged by a new, more powerful starter-alternator which can recover as much as 13kW from braking. Predictably, this allows the A8 to feature standard mild-hybrid power. You might remember I talked about ZF's hybrid 8-speed transmission not long ago. It contains a disc-shape electric motor inside the transmission casing. With this transmission, the A8 can utilize electric power to assist propulsion in coasting mode. This allows the car to coast at up to 100mph with the engine shut down for up to 40 seconds. The electric motor may also assist acceleration. The mild-hybrid tech is claimed to reduce fuel consumption by 0.7 liter/100km, or about 8 percent for a base petrol A8.

Comparatively, the engine range is more predictable. It consists of 3 petrol and 2 diesel engines:
  • 3.0 TDI V6, 286hp;
  • 3.0 TFSI V6 with single turbo and Miller-cycle capability, 340hp;
  • 4.0 TDI V8 with twin-turbo and e-booster, 435hp and 664lbft;
  • 4.0 TFSI V8 with cylinder deactivation, 460hp;
  • 6.0 TFSI W12 with cylinder deactivation, 585hp.
The last one is e-tron, a PHEV combining the 3.0TFSI engine, an electric motor and a 14.1kWh lithium battery for a combined output of 449hp and electric range of 50km. Again, the electric motor is part of the ZF Hybrid transmission, but it opts for the largest, 122hp, motor.



The A8 feels big and heavy only when you hustle it on narrower, twistier roads, where understeer takes control.


As expected, Quattro system is standard across the range. It uses crown-gear center differential to split torque 40:60 front to rear under normal driving conditions. Active rear differential and active rear-wheel steering are optional. Besides, the A8 features high-tech headlights with LED matrix beams and laser spot, OLED taillights, remote self-parking technology and active noise cancellation. To call it the world’s most advanced car is not overstated.

In the Cabin

The cabin of A8 is a stark contrast to that of Mercedes S-class. While the S-class is curvy and classical, the A8 is cool and avant-garde. Both employ top-notch materials, but the leather in Audi is harder, the seats are firmer and the whole ambience is not quite as inviting. IT addicts might prefer the Audi though, because it has replaced the MMI control with a haptic touchscreen on the transmission tunnel, whose operation is certainly easier once you have learned it. There is another touchscreen on the center console, and the instrument pod is filled with “Audi Virtual Cockpit” high-definition TFT screen. Moreover, the touchscreen are covered with glass which runs seamlessly across the dashboard and transmission tunnel. Fit and finish is typical Audi grade, which means second to none.

Expectedly, the cabin is spacious. Even in standard wheelbase form the rear seat has generous legroom and headroom. Long-wheelbase passengers get reclining seats, massaging and warming footrest and individual infotainment systems.


While the S-class is curvy and classical, the A8 is cool and avant-garde.


On the Road

As a luxury limousine, the A8 does not disappoint on the road. Its air suspension delivers smooth and quiet ride on most roads. Only on the bumpiest roads you will find it does not quite match a Mercedes S-class for ride suppleness and tire noise suppression. At this moment, the AI active suspension is not available yet, but prototype tests found it might not be as superior as imagined, especially over high-frequency sharp bumps where it is not capable to react quickly enough. That said, the standard air suspension is already good enough for most customers. The cabin is also very well insulated from the outside world, except a bit more wind noise than desired from the mirrors at very high speed. The engine is smooth and hushed in normal driving, including the base six-cylinder diesel.

The handling is no match for Porsche Panamera or Jaguar XJ, of course, but for a non-performance limousine it is good. Body roll is tightly controlled by the air suspension and adaptive dampers in Dynamic mode. Steering is accurate and well weighted, if numb. Grip and traction is abundant. 4-wheel steering shrinks it around town and stabilizes it at speed. The A8 feels big and heavy only when you hustle it on narrower, twistier roads, where understeer takes control.



For a non-performance limousine, its handling is good.


Although the new A8 gains around 100 kg, all its engines get more powerful and torquey, so performance is still improved a little. Even the base 3.0TDI offers respectable performance, capable of 0-60 mph in 5.6 seconds, although it sounds coarser when pressed. The petrol 3.0TFSI is faster still at 5.3 seconds, but the diesel feels more effortless at low speed due to its superior torque. It does run quieter and rev more cleanly. Meanwhile, the 4-liter petrol V8 is a lot stronger, sounds better yet runs smoother still, but I suppose most customers, especially Chinese, will be settled with the more economical petrol V6. The diesel V8 is a marvelous motor, as on SQ7, but it is probably over the top, unnecessarily complicated and costly to build. The range-topping W12 is not available yet, but its sibling works fine on Bentley Continental GT. Just pay attention to its weight and thirst.

The new A8 is an all-round luxury limousine. It does the luxury thing remarkably well and feels very well built. Dynamically, it is also a noticeable improvement from the past and should satisfy most customer’s expectation. Unlike the 7-Series or XJ, it has no particular weakness, save the conservative styling perhaps. Nevertheless, Mercedes S-class just feels a tad better in key aspects – the styling is more tasteful, the interior more special, the ride more comfortable and the refinement level even higher. While Audi is closer than ever, it still fails to rock the King from its seat.
Verdict: 
Specifications





Year
Layout
Chassis
Body
Length / width / height
Wheelbase
Engine
Capacity
Valve gears
Induction
Other engine features
Max power
Max torque
Transmission
Suspension layout

Suspension features

Tires
Kerb weight
Top speed
0-60 mph (sec)
0-100 mph (sec)
A8 3.0TDI
2017
Front-engined, 4WD, 4WS
Aluminum-steel spaceframe
Aluminum
5172 / 1945 / 1473 mm
2998 mm
V6, 90-degree, diesel
2967 cc
DOHC 24 valves
VTG turbo
CDI
286 hp
442 lbft
8-speed automatic
F: 5-link
R: 5-link
Adaptive air spring+damping

235/55R18
1975 kg
155 mph (limited)
5.6 (c)
-
A8 3.0TFSI
2017
Front-engined, 4WD, 4WS
Aluminum-steel spaceframe
Aluminum
5172 / 1945 / 1473 mm
2998 mm
V6, 90-degree, Miller/Otto-cycle
2995 cc
DOHC 24 valves, DVVT, VVL
Turbo
DI
340 hp
369 lbft
8-speed automatic
F: 5-link
R: 5-link
Adaptive air spring+damping

235/5518
1920 kg
155 mph (limited)
5.3 (c)
-
A8 4.0TFSI
2018
Front-engined, 4WD, 4WS
Aluminum-steel spaceframe
Aluminum
5172 / 1945 / 1473 mm
2998 mm
V8, 90-degree
3996 cc
DOHC 32 valves, DVVT
Twin-turbo
DI, cylinder deactivation
460 hp
487 lbft
8-speed automatic
F: 5-link
R: 5-link
Adaptive air spring+damping,
active electric actuator
-
est 2050 kg
155 mph (limited)
4.4 (est)
-




Performance tested by: -





Year
Layout
Chassis
Body
Length / width / height
Wheelbase
Engine

Capacity
Valve gears
Induction
Other engine features
Max power
Max torque
Transmission
Suspension layout

Suspension features

Tires
Kerb weight
Top speed
0-60 mph (sec)
0-100 mph (sec)
A8 4.0TDI
2018
Front-engined, 4WD, 4WS
Aluminum-steel spaceframe
Aluminum
5172 / 1945 / 1473 mm
2998 mm
V8, 90-degree, diesel

3956 cc
DOHC 32 valves
Sequential twin-turbo + electric turbo
CDI
435 hp
664 lbft
8-speed automatic
F: 5-link
R: 5-link
Adaptive air spring+damping,
active electric actuator
-
est 2100 kg
155 mph (limited)
4.4 (c)
-
A8 L 6.0TFSI
2018
Front-engined, 4WD, 4WS
Aluminum-steel spaceframe
Aluminum
5302 / 1945 / 1488 mm
3128 mm
W12

5952 cc
DOHC 48 valves, DVVT
Twin-turbo
DI, cylinder deactivation
585 hp
590 lbft
8-speed automatic
F: 5-link
R: 5-link
Adaptive air spring+damping,
active electric actuator
-
est 2175 kg
155 mph (limited)
3.9 (c)
-
A8 L e-tron
2018
Front-engined, 4WD, 4WS
Aluminum-steel spaceframe
Aluminum
5302 / 1945 / 1488 mm
3128 mm
V6, 90-degree, Miller/Otto-cycle + electric motor
2995 cc
DOHC 24 valves, DVVT, VVL
Turbo
DI
340 hp + 128 hp = 449 hp
369 lbft + 258 lbft = 516 lbft
8-speed automatic
F: 5-link
R: 5-link
Adaptive air spring+damping,
active electric actuator
-
est 2300 kg
155 mph (limited)
5.2 (est)
-




Performance tested by: -





AutoZine Rating

A8



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