The 6s: Audi AG

2.7L Twin-turbo DOHC V-6 Audi AG engineers say they've had it with hearing the press - and more than a few customers, no doubt - whine about Audi's ostensible disdain for competitive engine performance. After all, Audis are supposed to bring technology to the fore - and in the automotive milieu, performance and technology always have been inextricably linked.

We've sung past praises for Audi's 5-valve-per-cylinder philosophy, yet the technology, admirable though it is, never has totally rectified the company's penchant for comparatively small-displacement engines.

So Audi's fed-up engineers have strapped a couple of low-inertia turbochargers to what normally would be a too-small - though still artistically 5-valved - 2.7L DOHC V-6. Voila! Snuff one performance-deficit problem.

Audi knows turbos, folks. The small forced-induction units, one for each cylinder bank, stuff in air so quickly that the 2.7L's grunty torque of 258 lb.-ft. (350 Nm) is delivered in full at just 1,850 rpm. Forget the old saws about turbo lag. It's just not home in this engine.

Also on duty at each cylinder bank is an intercooler to chill the intake air, making it more dense and thus able to carry more combustion-sustaining oxygen. Then there's the variable intake timing and a variable-volume intake manifold. Lording over it all is a wonderfully precise electronic throttle, which also helps to cut turbo lag and coordinate the machinations of all the variables.

Don't overlook the availability of 250 hp, either. That's almost 93 hp/L; combine it with that awesome off-the-line torque and it produces a 4-door luxury/sport sedan that vaults from standstill to 60 mph (97 km/h) in 6 seconds.

What's most fun about the A6 2.7T (this engine's also offered in the A4 bodyshell, known as the S4) is the way it effortlessly pulls the outlandishly tall gearing of the delectable 6-speed manual transmission. With the A6 2.7T, not only is sixth gear overdriven, but so is fifth - and even fourth! The Audi's 0.684:1 sixth-gear ratio is the lowest you'll find anywhere but with the huge-engined Chevrolet Corvette 6-speed, and even the mighty 'Vette doesn't pull an overdrive ratio in fourth gear.

Our only reservations are the retrograde use of a cast-iron block (for some reason, the Volkswagen Group has an iron fetish when it comes to cylinder blocks) and rather disastrous fuel economy. One of the points of turbocharging is to enable the use of less displacement - and subsequently less fuel - but Audi's 2.7L DOHC turbo V-6 gulps unleaded with abandon; the A6 2.7T toiled to return 20 mpg (11.8L/100 km) on a long interstate trip mixed with brief around-town spurts.

Never mind that, though. Audi's 2.7L twin-turbocharged V-6 provides right-now thrust - and right-now performance credibility for Audi. This engine makes the A6 2.7T the most invigorating sport/luxury sedan we've tried in a long while.