How to Upgrade the Performance of an Audi RS4

1. Perform a full vehicle tune-up (including changing all critical fluids, such as oil, coolant, transmission fluid and replacing the spark plugs/ wires). Before modifying the RS4 for additional power, make sure it is in peak running condition; tuning the engine to increase output will undoubtedly place more stress on several components, causing faulty or worn out parts to fail.
2. Install a high-flow intake. This can range from a sinple drop-in air filter upgrade, to an entire cold air system, which replaces the factory induction piping. This allows the engine to breathe better for faster turbo spool up, and more power and torque at high engine speeds.
3. Add an aftermarket exhaust. The factory exhaust system, although quite capable, is designed to meet stringent noise and emissions levels, installing larger diameter exhaust piping will reduce back pressure and liberate more ponies throughout the RPM band.
4. Install a custom ECU. Now that the critical intake and exhaust systems are upgraded, its time to maximize performance. The ECU can be reprogrammed or replaced to provide custom fuel and timing maps. This not only dramatically increases horsepower, but also ensure a smooth running vehicle with proper idle and engine speed limits.
5. Tune your RS4 on a 4 wheel drive Dyno. In addition to measuring vehicle horsepower over the entire power-band, it provides a safe environment to adjust various settings such as fuel pressure, boost levels and will further tweak power delivery on both pump gas and racing fuel (if desired).