A stronger AMS shift rod center carrier from a later B6 model helps keep things bulletproof, assuring positive shifting and supporting the gear stack better-even with the big increase in torque. The power to the rear wheels is multiplied by the stock 4:11 ring and pinion gear set, then divided by a more positive Stasis clutch-type rear limited-slip differential, which continues to transfer torque even with cornering induced wheel lift.
To go fast on the racetrack requires more than just an engines motivating power. The car must be able to stop repeatedly from high speeds. Stoptech, master purveyors of balanced braking systems, was called upon to handle the job of stopping the heavy Audi. Huge 332mm front and 328mm rear ventilated two-piece rotors are clamped by 4-piston ST40 front and 2-piston ST20 rear calipers. Performance Friction's 01 compound brake pads are used up front with Hawk HPS pads in the rear, helping to maintain optimal balance. Motul RBF 600 brake fluid is pushed by the stock master cylinder through stainless-steel brake lines to the calipers. The calipers' piston bores are sized to work exceptionally well with the stock master cylinder bore diameter.
The suspension of the S4 is what really makes the car all come together. The centerpieces of the suspension system are exotic custom-valved 3-way adjustable Penske remote reservoir dampers, wrapped with Eibach ERS springs of a secret rate and free length. The front shocks feature a velocity-sensitive damping curve, which is best suited to the nose-heavy Audi. Velocity-sensitive damping in Penskespeak means that there is a lot of low-shock damping force to control body motion for crisp handling, with reduced damping at the mid and beginning of the high speed range to allow compliance for medium to large bumps. For severe bumps, the damping force increases again to prevent the car from slamming through its wheel travel.
The rear shocks have linear compression damping for suppleness and to reduce tire shock of the rear-light Audi, while the rebound damping features a digressive curve with lots of low-speed damping to control body motion. A stock 29mm front anti-roll bar is paired with a 22mm H-Sport rear bar, both featuring spherical bearing end links. Custom upper arms with spherical bearing-ends control camber adjustment, while custom suspension links shod with spherical bearings remove every bit of squirm-inducing squishy rubber from the suspension. Finally, the stock steel front spindles were replaced with lighter aluminum ones from an RS4.
For track situations, the road is gripped with extremely sticky and lightweight Hoosier R3S04 DOT racing tires, sized 245/40R-17. The R3S04 is fast becoming a must-use item if you want to win at time attacks. The Hoosiers are wrapped around 9.5x17-inch custom CCW classic mesh wheels. For street use, 18x9.5-inch Speedlines are used with more pedestrian Dunlop Super Sport rubber measuring 245/35R-18. To clear the big tires, many hours were spent contouring the fenders and doors for the big Hoosier rubber. The end result is a body that looks stock but is subtly flared.
The car is currently the terror of NASA's West Coast Time Trial series, holding many lap records at most of California's tracks. Flying in from NYC for each event, Pat has racked up enough frequent flyer miles to rest in the executive lounge and take free exotic vacations. Unfortunately, Pat missed 3 events during the 2005 season due to work commitments and ended up placing third in overall points in the TTB class.