The Audi S4 is a high-performance version of the compact executive A4 model. The A4 was originally built in 1991 until 1994 and was a performance-oriented version of the 100 saloon/sedan. All of the S4 models that have been manufactured since 1997 have been based on the Audi A4 as well as the S4. Although there are many similarities between the S4 and its Audi siblings, including the 100 and A4, there are a number of differences as well. The S4 has a much firmer suspension as well as upgrades brakes, larger roadwheels, and a distinctive sheetmetal body.
All variants of the A4 have longitudinally oriented front-mounted engines as well as a single turbocharged 2.2 liter inline 5-cylinder engine that is powered by the original C4 version, as well as a 2.7 liter twin turbocharged V6 engine that was also used in the B5 generation of vehicles. Both the B6 and B7 models use the same 4.2 liter V8 engine, which marked the first time that a V8 engine had ever been used in a compact executive car. This update made the S4 an official competitor with the BMW M3 which used a 3.2 L inline 6 engine at the time.
Every version of the S4 has had a transmission mounted at the rear of the engine in a longitudinal orientation and has only been available as standard with Audi’s Quattro 4-wheel drive system, using the Torsen-based center differential system. All versions of this vehicle have been built at Audi’s plant in Ingolstadt, Germany, and have been available as both 4-door five-seat and 5-door five-seat Avant body styles ever since their introduction to the market in 1991. There was also a 2-door four-seat Cabriolet or convertible S4 version that was introduced as part of the B6 and B7 generation A4 lineups.
At the time of its introduction, the C4-based S4 was available just one engine, which was a turbocharged and intercooled version of Audi’s 2.2 liter 20-valve inline-five-cylinder engine. This engine displaced a total of 2,226 cubic centimeters and came equipped with an advanced Bosch Motronic electronic engine control unit or ECU. The S4’s engine has a power output of 169 kilowatts and at 5,900 revolutions per minute as well as 350 newton meters of torque. The engine that was used in this vehicle unequivocally made it a powerplant, even by modern standards.
The second generation of the B5, which started production in 1997 and ended in 2002, was available in the form of a saloon or sedan as well as an estate or wagon, and the S4 Avant was first introduced in 1998. Production of this vehicle came to a sudden halt in September of 2001, however, but it was still sold with the next generation B6 platform throughout all of 2002 in North America. The B5 S4 has a 2.7 liter twin-turbo third-generation V6 engine with a cast iron cylinder block as well as two lightweight aluminum alloy cylinder heads.
The most recent generation of the S4, named the B8, started production in November of 2008 and was based on the Volkswagen Group MLB/MLP platform. One of the differences between this latest model and its predecessors is that it will only be available for purchase as a four-door five-seat sedan or a five-door five-seat Avant or estate. The 2-door four-seat Cabriolet version now belongs to the Audi S5 Cabriolet and new coupe. This new B8 S4 uses a smaller displacement 3.0 liter TFSI V6 engine with forced induction through a Roots-style Eaton mechanical supercharger. Overall, the S4 is a very impressive vehicle with some cutting edge technology and a sleek design that is still very popular with consumers.