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Audi S4: You won't miss those two cylinders

Rafay Ansar

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Raw figures rarely relate the whole story. But in the case of the fourth-generation Audi S4, they do provide a reliable guide as to the overall effectiveness of its new 3.0-liter V6.

Running a Roots-style supercharger that sits between the cylinder banks and operates at a maximum 24.7 psi, the V6 cranks out 333 hp at 5,500 rpm. This is down 11 hp from the third-generation S4's naturally aspirated 4.2-liter V8.

But the blown V6 also delivers 22 lb-ft more torque than the V8, an impressive 324 lb-ft being released between 2,900 rpm and 5,300 rpm. So there is no great hardship in the loss of two cylinders and 1.2 liters of displacement.

It is sufficient, Audi claims, for an official 0-to-62-mph time of just 5.1 seconds-- 0.8 second less than the old S4 and just 0.2 second shy of the time Audi quoted for the last RS4. A more-telling indicator of real-world performance, however, is the 50-to-75-mph fourth-gear time of just 4.4 seconds.

That is quick by any standard and reflects the effectiveness of the V6's prodigious torque in shifting the S4's 3,637-pound curb weight. Top speed is still limited to 155 mph, but there is little doubt the new Audi would haul beyond this if left to run all the way to its 7,000-rpm cutoff in top gear.

What is even more impressive is that the S4's supercharged V6 achieves all this with 27 percent better fuel economy than the V8. Audi puts the combined fuel-economy rating for the new S4 at 24.9 mpg.

As S4 tradition dictates, power is channeled to all four wheels via a standard six-speed manual gearbox. You can also choose a rapid-fire, seven-speed twin-clutch unit. But beware: Despite offering a manual mode and remote shift paddles, it always acts like an automatic.

Rather than holding on to gears as a proper manual does, the slick-shifting unit automatically changes up a gear when the revs reach 6,800 rpm--about 200 rpm shy of the redline. As with all of its new models in recent times, Audi has given this latest S4 a nominal 40:60 front-to-rear apportioning of drive power.

The new S4 also is the first model from Ingolstadt to receive what Audi describes as its sport differential--a complex torque-vectoring gear set that acts like a traditional mechanical locking differential by varying the amount of drive going to each rear wheel. When sensors within the electronic stability program detect understeer during cornering, the sport differential provides greater drive to the outside wheels to help provide the car with a more neutral trajectory. The opposite goes for oversteer, the sport differential delivering more drive to the inside wheels.

We've yet to drive the S4 in manual guise, but the optional twin-clutch gearbox (there is no automatic option) encourages spirited driving. Its tightly staked ratios help to make the most of the flexible qualities of the engine. Upshifts are performed in a crisp and smooth manner--even at high revs--with a distinctive bellow from the engine as each gear is engaged and boost pressure is created by the supercharger is dumped, while the electronics are clever enough to provide an alluring blip on the throttle on the downshifts.

Since its inception in 1997, the S4 has become a key model in Audi's efforts to provide its lineup with a more sporting flavor. While lacking the overall excitement afforded by its more heavily focused RS4 siblings, the S4 has nevertheless built up a solid following, thanks to its typically effortless performance and the dynamic security offered by its standard four-wheel-drive system.

This new one continues in the same vain, but adds one important element: added entertainment. Based on Audi's new MLP platform that provides significant improvements in weight distribution, it is more willing and responsive that just about any four-door Audi has produced.

There is an inherent sharpness to its actions that make it a much more engaging car to drive than its predecessor. It all starts with the steering, which is both direct and well-weighted. This is backed up by excellent body control and seemingly endless levels of grip. Then there's the S4's ability to get its power down without any undue fuss in any weather and/or road conditions.

It all results in fluid handling. Arriving in a corner at high speeds still induces understeer, but the actions of the sport differential ensure it never builds to quite the same level as before, and there is far less interruption from the ESP system. Audi has engineered its new system to vary the drive going to each of the rear wheels both under load and on a trailing throttle. The upshot is a more stable feel during cornering and higher apex speeds.

Another area in which the new S4 displays a clear advance on the model it replaces is in ride quality. With the addition of electronic dampers for the first time, it gives the driver the choice between three levels of stiffness--comfort, automatic and dynamic. A longer wheelbase and increased track widths help, of course. But no matter what mode you choose, there are far greater levels of compliance and more control from the individual suspension components when the surface turns nasty, providing the new go-fast Audi with improved comfort and refinement.

Buyers can option their car up with Audi's so-called drive select system, which provides the basis for sharper and more responsive actions by remapping the characteristics of the throttle, transmission shift points, dampers and steering--the latter receiving a low-friction axial transmission that provides whipcrack attributes. It's probably the best steering of any Audi model right now--the R8 included.

If the idea of a rapid but practical everyday car possessing true all-season ability and bulletproof quality appeals, we wouldn't talk you out of it. Not when Ingolstadt is promising to the S4 will land here at a price that goes against the trend by undercutting that of its predecessor.

While the decision to replace the S4's V8 with a supercharged V6 has robbed it of some of its aural appeal--some might say soul--its real-world performance is never in doubt. This is a fast car. An advanced new driveline featuring the latest in four-wheel-drive technology also helps provide newfound levels of agility.

The S4 is now a much more rounded car than before, one that is sure to provide the BMW 335i with its stiffest competition yet when it lands here next year. The only problem for prospective buyers is whether to opt for the style of the sedan or the versatility of the wagon. Whatever you choose, you won't be disappointed.
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