Audi introduced the S4 nameplate in 1991 as the sport version of the Audi 100 C4. The original S4 was a high-performance, turbocharged five-cylinder sedan and Avant that helped establish Audi’s modern S-car identity. In 1994, Audi renamed that first S4 generation to S6, which ended the original S4 badge after a short initial run.
The S4 name returned a few years later on the A4-based performance model line, beginning the second major chapter for the nameplate. From that point onward, S4 became the standard designation for Audi’s executive-sports variant of the A4 family, offered across successive generations and body styles such as sedan, Avant, and, in some eras, cabriolet. Over time, the model evolved from its early five-cylinder roots into the V6-powered S4s that became central to the badge’s later identity.
Enthusiasts value the S4 for bridging Audi’s everyday practicality with its performance heritage, especially because it connects the brand’s turbocharged, quattro-equipped early-1990s cars with the more refined A4-based S models that followed. The badge has remained an important part of Audi’s sporty middle-class lineup ever since, and it is still in production today in market-dependent forms.