TESTED

Whether you walk into a bar and order a double, or double down at the blackjack table, or, for those opposed to vice, play a friendly game of mixed doubles tennis, doubling is a call to action. It’s a catalyst for excitement and proof that you’re packing more into your day. Why else would there be racing roller coasters or double-barrel shotguns? Doubling works in cars, too. Think of the Audi A8’s new 4.0-liter V-8 as a double dose of Audi’s spectacular 2.0-liter turbo four. Two 211-hp turbo fours fused into one 420-hp twin-turbo V-8 make for a very quick A8L.

Audi assures us that the A8L’s 4.0-liter is a depressurized version of the 520-hp engine in the S8. It doesn’t really feel that way. A charge to 60 mph takes 3.9 seconds—Corvette territory. Stay in it, and the long-wheelbase A8L will pass the quarter-mile mark in 12.4 seconds at 112 mph, a half-second and 6 mph behind the S8. Something this big, this aluminum, this luxurious, and moving this quickly usually flies, too. But the A8L stays grounded at its 131-mph electronically limited top speed. In a previous life, before double turbos, the 372-hp A8L 4.2 registered a relatively mundane 5.1 seconds to 60 mph and a quarter-mile time of 13.8 seconds at 103 mph.

A lazy throttle is the only dissonant note in Audi’s symphonic big sedan. A slow roll or a casual step into the throttle from a stop is largely ignored. Push past the dead zone, and the car awakens startled, lurching forward on the tug of torque that peaks at 406 pound-feet. The lethargy mimics turbo lag, but the culprit is more likely a throttle calibration that is initially unresponsive, presumably to smooth step-off acceleration. Instead, it does the opposite.

The rest of the A8L is in tune. From the driver’s seat, the car feels less intimidating than the rest of its class of leviathans. The A8L’s cowl seems lower, the leather softer, and the instrument panel and controls less daunting. Drive it at night, and the ceiling-mounted lights cast a halo above your head. We did find ourselves reaching a bit for the knob that controls the radio, phone, navigation, and vehicle settings. Repositioning it behind the shifter would help. The goofy shifter doesn’t always call up the gear we thought we asked for, either, but now we’re reaching for complaints.

Out on the highway, the A8L’s thickly applied refinement keeps the driver at a ­distance; the machinery is hardly heard, and the structure barely registers wheel impacts. Start working the steering, the brakes, and the engine, and each component readies itself to serve at a moment’s notice—automatic shocks tighten, in sport mode the gearbox holds the lower cogs, and this Audi limo begins to act more like an RS5, albeit one with a 40-inch waistline.

The 4.0T-powered A8L inevitably calls into question the purpose of the more expensive S8, as the former is remarkably agile and not far off in the drag-racing department. At a base price of $88,095, the A8L (the S8 is only available with a regular wheelbase) undercuts the S8’s opening bid by more than $20,000. The S8 trumps the A8L in braking and roadholding, but a set of summer tires would go a long way toward closing those gaps. Both cars share the ­double-2.0T, er, the 4.0-liter V-8. The S8 is a little quicker, but only those obsessed by the numbers will notice. We’d save the money. It’s not as if the S8 is doubly powerful, though there’s an interesting idea...