Right car, wrong timing? At a glance, it would seem that way. The new arrives in the midst of a global economic slump. It was unveiled in October at the Paris show, where hybrids and electric vehicles stole the limelight, and it unashamedly advertises the motto Vorsprung durch Technik (Advancement through Technology) when everybody is talking low emissions and high mileage. Look closer, though, and the new S4 emerges as a surprisingly sensible proposition. It is expected to cost about the same as the car it replaces and it bristles with torque, yet it should deliver about 24 mpg overall (EPA figures haven’t yet been released). At the same time, it’s a tour de force that employs trick steering, chassis, and driveline setups to beam you from point A to point B quicker than some of its rivals.
But who, exactly, are these rivals? Audi identifies them as the and the Mercedes-Benz C63 AMG, but the 333-hp S4 falls between BMW‘s 300-hp 335i and the 414-hp M3. It also falls between the 268-hp Mercedes C350 and the 451-hp C63. The upcoming RS4 sedan and RS5 coupe, which both should get about 450 hp and 330 lb-ft of torque from Audi’s 4.2-liter V-8, likely will arrive in 2010. For now, though, the highest-performance version of the new A4 is the S4. It won’t go on sale in America until fall 2009 as a 2010 model and then only in sedan form: farewell, ultra-low-volume S4 wagon and convertible.
A comparison of the basic engine specs of the old S4 and the new car does not bode well: only six cylinders instead of eight, 3.0 liters of displacement instead of 4.2 liters, 333 hp instead of 340 hp. Are we getting shortchanged here? We are not. Maximum torque, that crucial parameter for drivability, increases from 302 to 325 lb-ft, and it is now available between 2900 and 5300 rpm rather than peaking at 3500 rpm. And although the curb weight is about the same, Audi claims that the new S4 surges from 0 to 60 mph in 5.1 seconds, outsprinting the old S4 by about half a second.
While most supercharged engines develop their sweet spot between 3500 and 5000 rpm, the direct-injected 3.0-liter V-6 shoots fireworks all the way to its 7000-rpm redline. It thus combines the low-end torque of a force-fed engine with the top-end energy of a high-revving, normally aspirated one. The result? Enough power to rocket the S4 from 50 to 75 mph in only about 4.5 seconds in fourth gear, says Audi.
The seven-speed version of Audi’s dual-clutch S tronic transmission, which makes its U.S. debut in the S4, is definitely the gearbox to go for, although a six-speed manual is standard. The main advantage of the dual-clutch arrangement is, of course, the totally seamless torque delivery, which helps maintain momentum during gearchanges. In auto mode, the system can be outfoxed by certain borderline situations, such as aborted overtaking maneuvers or a sudden shift of driving style, but the chips learn fast, and the fluency of the S tronic never ceases to amaze.
To get the best out of the standard Quattro all-wheel drive and the 40/60 front-to-rear torque split, specify the optional new sport differential, which distributes torque between the rear wheels in a progressively variable fashion. It works under trailing throttle and even when the gearbox is in neutral. As the vehicle turns in, the diff diverts most of the propulsion forces to the outer rear wheel. This reduces understeer, allows you to select a more moderate steering angle, and improves roadholding and directional stability.
To specify the sport diff, you must first opt for Audi Drive Select, which includes adjustable dampers and so-called Dynamic Steering. Drive Select offers three different tuning stages-comfort, normal, and dynamic-and the ability to dial in your preferred calibration of the engine, transmission, dampers, steering, and differential. Dynamic mode provides a nice mix of sharpness and balance, of tactility and feedback, of intuition and agility. It is still possible to deactivate stability control, but this move doesn’t yield much anymore, because the front-to-rear and side-to-side torque flow is managed to perfection by a couple of electronically controlled gearsets. As a result, hard cornering is no longer a mix of more or less understeer. Instead, the nose turns in, the rear end tracks to match, and the ensuing four-wheel drift is easily modulated by throttle and steering in much smaller nuances than before.
The electronic damper control fitted to the S4 is a conventional system that varies the diameter of an orifice controlling the oil flow. More important than the switchable dampers are the changes made to the base A4 suspension. To reduce unsprung weight, Audi replaced certain chassis elements made of steel with aluminum. To limit unwanted body movements, the company fitted tauter springs and dampers, and it lowered the ride height by nearly an inch. These modifications are all welcome, but those who live in areas with smooth roads might pine for nineteen- or twenty-inch wheels, as the S4’s wheelhouses certainly have room for them. Unfortunately, Audi of America won’t offer anything other than the standard eighteen-inch rolling stock at launch.
Inside, the S4 is an A4 in monochromatic livery-black in the case of the car we drove. It sports redesigned instruments with gray faces, a special leather-wrapped steering wheel, comfortable and supportive power sport seats, and optional stainless-steel dashboard inlays. Inside and out, the new S4 is an undercover fast-lane warrior rather than a decaffeinated RS4.
Audi has created a product that is the epitome of efficiency. It is introverted in appearance and delivery but extroverted in character and ability. Call it pragmatic, if you wish. Call it multitalented, because that’s what it is. Call it the reincarnation of the Q-ship. All it takes to enjoy it is to adjust to the S4’s minimum-input, maximum-effect approach. And to hope that your stock portfolio allows you to consider buying one when it goes on sale here next fall.
On Sale: Late 2009
Price: $50,000 (est.)
Engine: 3.0L supercharged V-6, 333 hp, 325 lb-ft
Audi has rearmed its S4 with a more potent powertrain and chassis. A lighter, supercharged and intercooled 24-valve 3.0-liter V-6 supplies more torque but slightly less power than the retired 40-valve 4.2-liter V-8. An Eaton blower spinning up to 23,000 rpm skews the torque curve down the rev scale and up the lb-ft register. Between 2900 and 5300 rpm, 325 lb-ft of torque is available, versus the previous V-8’s 302 lb-ft at 3500 rpm. The power curve is dead level at the high end, with 333 hp available from 5500 rpm to the 7000-rpm redline (compared with the previous S4’s 340 hp).
Driveline upgrades include a new seven-speed dual-clutch automatic with a gear ratio spread 32 percent wider than the outgoing six-speed Tiptronic’s range for improved fuel mileage.
A new active rear differential uses a clutch-activated gearset overdriving the outside rear wheel to diminish understeer in tight bends. While the Quattro AWD system relies primarily on mechanical manipulation of torque distribution, electronic systems help out during snow and ice driving. The variable-ratio power steering and gas-pressure dampers also are actively controlled.
For improved handling and road feel, the front axle is shifted six inches forward, and the steering gear has been mounted ahead of the front wheels to an aluminum subframe, which is in turn rigidly attached to the S4’s steel unibody.