Audi RS4's Unconventional Rear-Turbo Setup Delivers a Whopping 730-HP and Incredible Speed

Even though it may look unassuming, a strikingly powerful Audi RS4 B7-generation Avant, a force to be reckoned with, sits on the horizon of auto modifications. This capable performance wagon gets an added kick with the installation of forced induction, uncovering the car's immense tuning potential.

This compelling transformation comes to us courtesy of its owner, James, whose Audi RS4 features an unconventional turbo setup. Propelled by a turbocharged 4.2-liter V8 engine, the car delivers a formidable 730 horsepower at eight PSI of boost. This horsepower is complemented by a precision turbo setup and nitrous injection, which significantly enhances the mid-range power delivery.

However, what truly sets this build apart is the unusual location of the turbo. Unlike most configurations, the turbo in this Audi RS4 is mounted in the rear. This design is made visually captivating with a custom-made glass panel that provides a clear view of the turbo tucked beneath the trunk floor. The turbo, a Precision Turbo three-inch model, is paired with a 1.5-inch external wastegate and features a muffler with a valved option for a louder exhaust note. A water-methanol injection system is also added for an additional power boost.

Taking a personal approach to the build, James handled most of the modifications himself, with MRC tuning providing the calibration. Remarkably, the car still houses a stock engine without internal modifications, with the only additions being a custom CG Motorsport twin-plate ceramic clutch, upgraded engine and gearbox mounts, and a billet short shifter. A standard Bosch 9.1 ECU manages the car, while the suspension has been refreshed with Bilstein components.

Despite the significant modifications, the Audi RS4 manages to retain its inherent V8 characteristics, delivering a smooth, refined performance that left everyone impressed. James' attention to detail and his dedication to preserving the original aesthetics of the car make this build stand out from the crowd.

Plans to further enhance the power of the car are on the cards for James. His impressive build proves that you can relish a sleeper car without extravagant overhauls. And while American enthusiasts may feel a bit left out as the RS4 has been replaced by the RS5 Sportback, Audi has teased a new variant of the RS6 that promises to be a game-changer.