If silent travel is chief among your priorities for an ecofriendly vehicle, the Audi A8 hybrid is not for you. There isn’t much in the way of quiet, electric-only operation, which makes sense, of course, given that this isn’t a fully electric car. (You can run solely on electrons for about two miles at a constant 37 mph, and if you awaken the engine, EV mode will reengage automatically when you relax on the accelerator. Top speed in all-electric mode is 62 mph.) And although you might never notice its internal-combustion heart beating if you dawdle at or below the pace of traffic, the engine brings attention to itself with a subdued but noticeable growl once you call for any real power.
The sucking, squeezing, banging, and blowing noises come from the VW Group’s ubiquitous 211-hp, 2.0-liter four-cylinder, teamed here with a 54-hp electric motor that’s integrated with a ZF eight-speed automatic transmission. Electrical storage capacity is provided by a 1.3-kWh lithium-ion battery pack. Power is sent only to the front wheels. Combined and at full steam, the powertrain delivers 245 hp and 354 lb-ft of torque. This system is almost identical to the one offered in the A6 and Q5 hybrids.
We Suppose That’ll Do
We estimate the A8 hybrid can reach 60 mph in about 7.2 seconds; Audi claims a drag-limited top speed of 146 mph. It is not governed, and we found you can easily reach 155 or more mph on downhill sections of the German roads on which we drove. This kind of performance should be sufficient for most markets and customers. But it does not compare to the relentless power you feel when you step on the throttle of the 2011–12 BMW ActiveHybrid 7 (since neutered for 2013) or Lexus LS600hL. Nevertheless, piloting this A8 can be satisfying for hybrid lovers who drive without urgency. At that point, this A8’s hybrid system goes about its business unobtrusively. Up to 99 mph, you can do what VW Group brands like to call “sailing,” that is, if you take your foot off the gas, the electric motor doesn’t aggressively recapture energy, allowing for a smoother coasting experience. You’ll be all smiles at the gas station. At 37 mpg in the European combined cycle, the A8 hybrid is the most efficient gasoline-powered luxury sedan. For comparison, on the same test cycle, the Mercedes-Benz S400 hybrid gets 30 mpg, the LS600hL returns 25 mpg, and the 2011–12 ActiveHybrid 7 achieved 25 mpg. (We estimate ratings for the A8 hybrid on the somewhat more realistic EPA cycle at 24 mpg city and 34 highway.)During spirited driving, you can feel the electric motor lending a hand, a welcome boost during quick passing maneuvers as long as the batteries aren’t depleted, which happens all too quickly. As for when the road begins to bend, it isn’t much fun to test the A8 hybrid’s limits. We love piloting any A8—and we include the sporty S8 here—and it’s our reigning champion in the segment, but this is the least dynamic of the bunch. Even with 290-ish pounds of hybrid gear, at an estimated 4150 pounds, the car isn’t very heavy versus its competition. But with power routed only to the front wheels, this hybrid relentlessly and gracelessly pushes through corners; we wished for Quattro. There is only one other front-drive A8 variant: the Europe-only 204-hp, 3.0-liter V-6 diesel version, which incidentally gets even better combined mileage than the hybrid at 39 mpg on the EU cycle. The brakes are relatively numb, but the transition from electric recuperation to hydraulic braking is well camouflaged.
Other A8s Make More Sense
Otherwise, the A8 hybrid is an exceedingly comfortable long-distance cruiser, and its four-cylinder-based powertrain is sufficient if performance and bragging are not your main objectives. But how much sense does the hybridization make? Its drawbacks include extra weight and complexity, the gas tank shrinks from 23.8 to 19.8 gallons, and trunk space is down from 18 cubic feet to a far-less-usable 11.8.
July 2012 || BY JENS MEINERS || MULTIPLE PHOTOGRAPHERS