It was a very challenging task to take one of Audi's most accomplished cars, the S4, and improve its performance without compromising the essential "rightness" of the car. We consider our efforts a success.
In Part 3, Project S4 acquired a substantial power upgrade to its 2.7-liter turbocharged V6. APR stepped in with its Stage 2-plus setup, increasing boost from the stock 7 psi to an astonishing 1.0 bar--just over 14.5 psi. On my first test drive with the 100-oc
Buying a factory-turbocharged performance car is often done for one reason--"tuneability." Thousands of dollars can be spent increasing a normally aspirated engine's output by a nominal amount, but a turbocharged car's power can be effectively upgraded by a si
Notice a new project car on this month's cover? Did you think we would overlook modifying what is possibly the most "tuneable" European car right out of the box? When the Audi S4 reached U.S. soil in 2000, it was an instant winner. The relatively affordable Eu
From the factory, the Audi S4 is well balanced. Standard features include large brakes with twin-piston calipers, a powerful twin-turbocharged V6 motor, and a street suspension to harmonize the S4's overall performance. The stock suspension is soft enough for