Engineering changes ranging from mild to massive have added to the complexity of buying a used Audi S4, but all S4’s come with Audi’s Quattro all-wheel-drive system as standard equipment. The changes separate the S4 from the more sedate Audi A4 include subtle exterior changes, more powerful engines, a sport suspension package and upgraded brakes. S4 interiors also generally have a noticeably sportier feel when compared with the base model car.
The changes that have been made from generation to generation are rather significant:
The first generation S4 was introduced in 1992. It was powered by a 2.2 liter inline-5 cylinder engine. A turbocharger was fitted to bring the net horsepower to 227. In 1994 the S4 name was set aside. However, a virtually identical S6 model was still available for purchase. Buyers should be aware modern S cars are generally not so closely related. Today, these early S4’s can be quite difficult to find in good condition, but clean examples do occasionally surface.
The second generation S4 made its debut in Europe in 1997. Three years later, a redesigned sedan (and its modern 2.7 liter bi-turbo engine) was brought to the United States. The 2.7 liter V-6 is a complex piece of machinery, and great care should be taken to ensure any potential purchases have been well cared for. This upgraded chassis (coded as the B5) marked the first time Americans were given the choice to purchase an S4 Avant.
The S4 saw another significant upgrade in 2002, when engineers chose to squeeze a 4.2 liter V-8 engine under the hood. This B6 generation also brought the Cabrio (or convertible) option to American buyers. The B7 S4 was released in 2005. This generation is powered by the same V-8 as its predecessor, but it is the first S4 to incorporate a 40/60 torque split. This means the Quattro system sends slightly more power to the rear wheels. Cosmetic changes were rather significant in this generation, making it a bit easier to differentiate from its older counterparts.
The B8 model became available in 2009, and once again brought a number of significant changes to the S4. The V-8 powerplant has been replaced by a supercharged inline-6 displacing 3 liters. The forced induction six cylinder makes slightly less power than the old engine, but low end torque is optimized, with full thrust available from just 2,900 rpm. This means the traditional V-8 grunt is still there, but it is partnered with a more reasonable average of 24 miles per gallon. As with all Audi’s, the S4 is sure to see further upgrades as new technology is released.