Audi RS 4

The Audi RS4 is a high-performance version of the Audi A4, a compact exclusive car produced by German automaker Audi. It slots above the Audi S4 as the fastest model in the A4 range.

B5 RS4 (1999-2001)

Audi introduced the first generation RS4 in late 1999 as the successor to the Porsche developed/RS2. The vehicle, like its predecessor, was available only as an Avant (station wagon), and was built on an existing platform, in this case the "B5" generation A4/S4. Base price was around 103,584 Deutsche Mark. The RS4 was available for sale in most of Europe and in some Latin American countries.

Power came from a modified version of the B5 S4's 2.7 L, twin-turbocharged V6 engine tuned by Cosworth Technology, featuring enlarged intake/exhaust ports on the cylinder heads, turbochargers and intercoolers, new induction and exhaust systems and a re-calibrated engine management system; a six-speed manual transmission and Audi's Quattro all wheel drive system were part of the package. The modifications were enough to bump the engine's power output from the 265 PS (195 kW/261 hp) and 400 Nm (295 ft·lbf) of the S4 to 380 PS (280 kW/375 hp) and 440 Nm (325 ft·lbf).

Even with a curb weight of 1620 kg (3568 lb), the RS4's powerful engine gave it the performance of a sports car. The 100 km/h (62 mph) mark could be reached in just 4.7 seconds and the 160 km/h (100 mph) could be achieved in just 11.6. Brakes were also developed in house by Audi/Cosworth Technologies not by Porsche as with the RS2. It now has 360 mm (14.2 inches) discs at the front and 312 mm (12.2 inches) at the rear gave the RS4 braking to match, needing less than 50 m (155 ft) to come to a full stop from a speed of 110 km/h (69 mph).

Audi produced 6030 units between 1999 and 2001.

B7 RS4 (2006-present)

After a long hiatus, the second generation RS4, now built on Audi's "B7" A4 platform, became available to European customers in the summer of 2006. It was introduced at the 2006]] North American International Auto Show in January and arrived in August 2006 in North America.

The B7 RS4 is an almost complete departure from previous RS cars, as it was launched as a sedan, with an Avant and Convertible version arriving later. Only the RS6 has gone this route before, the previous RS4 and RS2 were available exclusively as Avants. In addition, power comes from an FSI equipped, normally aspirated 4.2 L V8. This engine is very powerful, producing a total output of 420 PS (309 kW/414 hp), over 100 PS/litre. The engine also produces 430 N·m (317 ft·lbf) of torque. Curb weight is stated at 1650 kg (3634 kg). The RS4 is also equipped with the 14.3 inch front brake discs and eight-piston calipers from the Lamborghini Gallardo.