With so much new product being pumped out of Ingolstadt sometimes it is easy to take your eyes off the bread and butter of the Audi brand. Such is life right now for the four rings. With universal acclaim for the R8 supercar, Audi's return to the coupes of old with the A5 and S5, a relatively painless transition to the second generation TT, the ease with which the Q7 has entered the luxury SUV market and high end monsters such as the S6 and S8 receiving their fair share of praise, the brand-reviving A4 waits in the shadows for its chance to shine.
Road tests from abroad indicate that the B8 A4 - larger, more refined and chock full of goodies from the rest of the Audi lineup - will hold its own quite well, thank you. North Americans will need to mark their calendars for next fall's availability, however. That said, the S4 variant of the A4 remains a mystery to all since it was not revealed together with the A4 in Frankfurt in September.
Audi wants and needs a strong performance (sales performance that is) from the all important next generation A4. Meanwhile, enthusiasts have been turning to the S4 for many years for performance of a different type: on the road where it counts.
Long before many current Audi owners were even cognizant of the brand the so called UrS4 offered not only very capable performance, but a highly tunable platform with which to work. The venerable 20V turbo five powerplant was tweaked for 227-hp from the factory and pushed the car from 0-60mph in relatively quick 6.2 seconds. From Stage 1 chip upgrades to fully built RS2 conversions, the UrS4 offered the owner latitude on tuning bounded only by time and money.
History repeated itself some years later as the B5 S4, with its bi-turbo, six cylinder engine, again put a lot of meat on the bone for Audi owners looking to modify their rides. While tuning the UrS4 was always more in the realm of the old school monkey wrenchers, the B5 S4 had a much more proletarian owner base which enthusiastically and unreservedly ordered chip and exhaust upgrades to build upon the stock 250-hp offering. However whereas the stock K24 turbo in the UrS4 was largely bulletproof, the K03 turbos in the B5 S4 were at times prone to trouble. Enthusiasts took turbo issues in stride by using failures as the requisite excuse to pursue RS4-type tuning.
The B6 S4 was recipient of Audi's wonderful 4.2-liter V8 powerplant, and the B7 also saw FSI direct injection added to the mix to improve both performance and fuel economy. Gone were the sounds of spooling turbos and ubiquitous chip upgrades, replaced instead by the type of low end grunt and torque that only large displacement powerplants could offer. You really had to hand it to Audi too for squeezing so much out of such a compact and lightweight engine.
Unfortunately, enthusiasts have had very few options in regards to tuning their V8 S4s. Many have waited for the mainstream US tuners to sell a supercharger solution, but Europe's MTM still offers the only viable (and very expensive) system on the market. That means we must now focus on the B8 S4. So what do we know for certain?
Back in 2006 we speculated that high performance turbos would make their return at Audi. Indeed the new RS 6 Avant raised the bar considerably with its 580-hp twin-turbo V10 under the hood.
We have confirmed with inside sources that the B8 S4 will debut with a brand new 3.0-liter TFSI bi-turbo producing 330-hp. With this powerplant Audi can nearly match the B7's 340-hp output while providing even better performance figures. Manufacturer published (conservative) 0-60mph drops from 5.4 seconds to very low 5's, while the accompanying combined fuel economy rises from 17 mpg to over 20 mpg.
More importantly, at least from the enthusiast point of view, a return to bi-turbos means that modifying the B8 S4 to enhance its stock performance capabilities will be a more historically straightforward (and less expensive) endeavor. And lest we forget the all important marketing perspective, the 3.0-liter bi-turbo will also best a similar offering in BMW's 335i which weighs in at only 300-hp.
Delivering power to the ground reveals the other technological breakthrough which will debut on the new S4. It is given that it will employ Audi's revered quattro all-wheel drive, however it will not be just the active sport differential system which is centered around distribution of torque on the rear axle.
The B8 S4 will instead mark the debut of Audi's vectoring quattro system which will allow the dynamic allocation of torque to all four wheels. Audi's already improved driving dynamics thanks to its recent rearward bias will improve even further as the S4 gets the most neutral driving characteristics ever found in a performance sedan.
Timing remains a wildcard for the B8 S4. It is slated to go on sale in the States alongside the B8 A4 in fall 2008, meaning it will have to debut early next year. We put our money on a Big Apple debut at the New York Auto Show in April. In the mean time we have put together two brand new renders of the B8 S4 to help enthusiasts pass the time waiting.