Audi's new S4 comes to America with a racing pedigree that mixes championship-winning sparkle with the hard commercial business of selling a planned 50,000 new S4s worldwide. The latest S4 brings V8 brawn to the showroom, but turbocharged fives bought the legendary quattro its first appreciation in America [see: Audi's US powerhouse pedigree].

Since 2000 there's been a new V6 twin-turbo beat to Audi exploits in the U.S., a raft of wins (eight, all scored by double champion Michael Galati) and a trio of championships (successive 2001-2 Drivers and 2001 Manufacturers) in the Speed GT World Challenge. Sleuthing how the earlier federal 250-bhp S4 sedan became a wide-arch winner at over 400 bhp, I travelled to England to trace its family tree, then to Virginia International Raceway to drive this unique 4x4 track thriller.

An unholy but effective marriage between the earlier (not for USA) RS4 30-valve V6 powertrain and the S4 4-door silhouette was financed by Audi North America. Director Len Hunt supported a transatlantic program to create the test Audi S4 Competition as Audi NA chose the Speedvision GT series for its links to showroom cars. Former British Audi boss Hunt knew the winning ways of Audi Sport UK, and in Autumn 1999 they began S4 discussions through Rod Bymaster, Audi's loyal North American motorsport coordinator. Renamed Apex, the Brit outfit now supports the Volkswagen/Audi-owned Bentley at Le Mans. Utilizing its specialist quattro GmbH division, Audi delivered major basics (unmodified body shells and powertrains) to Britain for assembly. This was strictly a works-blessed program, not a full factory effort, as Audi Sport focused on the R8 as the megabuck program.

The S4 raced in America was a four-door with obsolete RS4 Avant five-door wagon implants. The metal craftsman's diabolically difficult job was to mate substantial RS4 three-quarter rear steel pressings to sedan arches. Originally they accommodated 9x18-in. BBS magnesium wheels. The front fenders and chin spoiler were also drawn from the RS4.

Speed World Challenge organizers at the SCCA employ a power-to-weight formula, plus restrictions on wheel rim widths, ensuring entertaining track action. A multi-colored automotive avalanche showcased six-cylinder soundtracks from Audi and Honda, their gruff V6s pitched against shrill straight sixes from BMW and Porsche's flat sixes, both out-blasted by menacing Corvette V8s and Chrysler Viper V10s.

During 2000, the organizers allowed a smaller splitter extension in carbon composites to improve the front end's aerodynamic "bite." That balanced a 20mm flap to the Sport rear spoiler, legacy from the 1997 racing A4 quattro. Also inherited from 2-liter A4 racers were dashboard panels, non-slip foot pedals, Audi side impact crash protection, carbon-fiber door trim and pit-stop air jacks.

CAD was enlisted to electronically draw components for fabrication. Aluminum top arms for the front and wishbone rear suspension allowed wheel cambers to be set to suit each track. Replacement anti-roll bars with blade twist sections and Uniball solid joints were installed. Cockpit bar adjustability was not permitted initially, but featured on 'our' '02 test S4.

Audi RS4 subcontractors Cosworth Technology race-modified the 2796cc bi-turbo, 30-valve bent six. Since the RS4 with five-valve-per-cylinder engineering offered 380 bhp in showroom trim, 450 bhp was not a challenge but simply a logical progression of the towering torque that Audi's V6 recorded as a prototype. The production five-valve heads were mildly modified at Cosworth Castings alongside showroom engines. Other for-the-track modifications embraced enlarged RS4 intercoolers, a competition exhaust system, Pectel electronic engine management (later race-improved in California) and a single-mass flywheel.

The tight, 1999-2000 four-month conception to race gestation timetable saw a single S4 make the first race It was transported straight from UK shakedowns to Champion Racing in Florida, which collected the corporate silver and red package and hauled it straight on up to Charlotte, NC for a March 25, 2000 debut. That solo S4 for Derek Bell qualified 17th on a 40-car grid, finishing a fighting ninth.

A sensational second round at Mosport in Canada saw a pair of S4s qualifying inside the top ten. The new S4 for Italian-born Ohioan Michael Galati (then 41) qualified a fine third and raced to a surprise second. Galati seized the S4's first pole position at twisty Lime Rock, but he was fifth at the finish. Another Galati second place was recorded over at Sears Point in California, but the mid-season saw the S4s sag, owing to persistent electrical misfires.

Las Vegas, the penultimate round in the Challenge, used a tight 2.25-mile modified oval circuit. Together with some rare rain, circumstances played to quattro drive strengths. Galati qualified fastest and led from start to finish. The tenth and final 2000 round was in San Diego and saw Galati make the top five. The silver dream-team Audis had done enough in their first season to place Galati second in the series, Bell twelfth.

I asked Galati how the S4 compared to the Porsches, Hondas and Mazdas that had brought him an enviable 10-year race record. "My family was always into Audi quattros, right back to the 5000 model in the '80s. I found it a bit strange at first, but always enjoyable. In a quattro things happen in a different way to a conventional car. The wheel is really where that quattro feeling starts, because the steering is very, very sensitive. It just seems to pick up on everything you need to know as a race driver."

Michael added, "The tires also last better with four-wheel drive, and you notice this in the high-temperature tracks [Texas registered 112*F!]. The turbo motor is unusually flexible, and off the start it is just dynamite! The first time I qualified in the top three, I set off from the standing start for the race and it was...well, like where is everybody? It is well suited to the tracks that put a premium on handling instead of dragstrip performance. It is a great drive that rewards real commitment into each corner, especially the high-speed stuff," grinned Galati with Italian gusto.

For 2001, it was left entirely to Dave Maraj-owned Champion Racing of Pompano Beach, Fla. [established in 1988 and now the world's largest single Porsche retailer] to develop and compete the S4 Competition. Technically, the car's altered significantly, Toyo tires were now mandated instead of BF Goodrich. An insider asserted, "The Toyo tire thing was good for us, because the quattro conserves rubber better than its opposition, and quattro 4x4 made the best use of the Toyo's limited abilities."

In 2001, Champion won the most races (4) of the S4's career, culminating in a double victory at Road Atlanta that netted both Driver and Manufacturers titles for Galati and Audi, plus a 1-2 finish for Galati and veteran Bell. In 2002, they fought for both titles down to the VIR wire but had to settle for just a repeat of the 2001 driver's title result. Honda's Acura NSX, driven by PD Cunningham, shaded them in the fight for a second successive makes crown. Maybe a four-door Audi and the NSX, Corvette C5 and Viper belong on different planets, but witnessing a trio of S4s streaking through a speed trap at 162 mph at VIR reminded us that 700-hp Trans Am Vettes make only 10 mph more. Champion Racing redeveloped the S4 hybrids for 2002 so that their UK origins were a distant memory. Under the technical guidance of Brad Kettler--who also tended the company's two ex-factory R8 racers--and S4 team leader Louis A. Milone, up to 16 employees covered 40,000 trucking miles annually.

Kettler and Milone reported that the S4 basics remained original. However, different regulations and tires enforced rapid changes in turbo boost and curb weight. Power? It was originally quoted at 450 bhp, but late 2002 investigation revealed that power ranged from an initial 400 bhp in 2000 to 420-425 in 2001 due to increased boost. The team reported a second boost increase for 2002 that allowed a 440-bhp peak, but the SCCA clipped boost again and "held us in the 430-bhp range for most of 2002," reported Champion. Curb weights zoomed in '02, ranging from 3,265 lb to a lowest of 3,050 lb, but Galati also carried an additional 80 lb of "success weight" during the year.

Paul Leeming was Champion's Cosworth liaison engineer, and they have never suffered an engine failure in three seasons, a massive complement to Audi, Cosworth and those who tended such overstressed production hardware. Pectel re-programming the V6's management for high ambient temps and violent altitude changes, and enhanced electronic and turbo boost reliability.

The quattro drivetrain emphasized production components such as the gearbox and shafts, mixed and matched from out of the Audi parts bins. Louis Milone said of the clutch in standing-start race duty, "We've been through four combinations and are now satisfied with a steel Tilton triple-plate unit." As specified in Britain, the front and rear differentials were rudely welded and locked. Now, though, Audi-supplied limited-slip differentials, including a Viscous coupling central unit, were installed. A ZF mechanical rear differential emerged from Audi, while a race-modified Torsen front limited-slip supports outstanding steering. Suspension was radically overhauled in 2001, a totally new Ohlins damping system replacing the original Penske units; Eibach springs remained. Stronger Champion forged alloy rollers of similar appearance and 9x18-in. dimensions replaced the BBS wheels.

The brake system was cruelly treated at the highest weight penalties on hot street circuits. Champion saw unparalleled component damage after summer's Washington, D.C. street race, while Galati sweated in the cabin torture chamber, with burning brakes. Such trials bonded Champion to Alcon, previously featured on many competition Audis. Their 360mm/14-in. front discs and 322mm/12.5 in. rears were allied to Pagid pads and six-piston front and four-piston rears by 02. If there is a weak link in the S4's armory, it is braking without ABS, unlike its rivals.

Now, it's my turn to trot an S4 with a different attitude around the stunning but sodden VIR track. I gaze down at the Motec digital dash, wondering if I'll sniff the 7200-rpm limit in any of six H-pattern gears--and briefly feel a sham, elongated like a formula car driver within this comparatively upright 3000-lb sedan. Activate ignition and power steering pump switches.

A distant Boeing jet spools up. That's the pump for the electronically assisted power steering reporting in. Assorted whines and 4x4 transmission grunts bounce around a metallic cabin. They fade behind the escalating engine soundtrack on departure from the world's largest turning circle. Time to assault prime Virginian blacktop, as it wends through verdant woodland.

An enraged 2.7 turbo conquers streaming wet surfaces incisively, allowing solid acceleration and multiplying my confidence. Tactile power steering aligns curves concisely, but the S4 shuffles wide in tight corners if the entry speed is not precision-matched to limited grip. The margin between great all-wheel drive grip and sudden 4x4 slides is as slim as an IRS refund. Harder still is judging braking distances, for there's minimalist upcoming wheel-lock information from the brake pedal.

After 45 minutes in the uber-S4 on its race-bald Toyos, the turbo rush from 4500 to 7200 rpm--with just a twist of neck attitude--remained the sweet spot. I enjoyed probing the rasping rev limit in fourth, yet the dry-mouth ride to utmost exhilaration was the waterside start and finish flight in sixth, when the S4 became a 4x4 speedboat, trailing spray for 100 yards but tracking trustily. For 2003, the Champion Audi team returns with a new race-ready RS6, and Audi NA will need all the help they can get in the fight against PTG BMW M3s and friskier Porsches.

Audi's U.S. Powerhouse Pedigree
Factory Audis first won in the U.S. with inline turbo fives. These 2.2 liters delivered 500 to 720 official horsepower in the squat Sport quattro for three years at Pikes Peak (1985-87). They were succeeded by circuit competitors such as the SCCA Trans Am 200 (1988 double title winner) and IMSA's GTO category with the fiery 90 spaceframe quattro, which could cut a single qualifying lap with 1000-bhp capability in 1989.

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