Audi RS4/RS5 B9 Tuning Guide

The Audi RS4 and RS5 B9 models offer an impressive combination of performance, luxury, and technology straight out of the factory. While many owners will be happy to leave their vehicles as they are, some may want to explore tuning options to enhance performance or the driving experience. Whether it's for a bit more power, a deeper exhaust note, or a louder turbo whoosh, tuning the RS4 or RS5 can take these vehicles to the next level.

In this guide, we’ll walk through the basic tuning options available for B9 owners, from simple upgrades to more involved modifications, broken down into two main stages: Stage 1 and Stage 2.

If you're seeking performance parts, check out our dedicated page for your B9 RS models here

Stage 1 Tuning: ECU Tune and Light Modifications

For those just getting started with tuning, Stage 1 offers a balanced combination of performance improvements without overhauling the car. The most common first step is an ECU tune.

ECU Tune
The ECU (Engine Control Unit) tune is the most effective way to unlock extra performance from your vehicle. By optimising the car’s settings, such as fuel mapping, boost pressure, and throttle response, an ECU tune can increase horsepower and torque. For the B9 RS4/RS5, a Stage 1 tune typically adds around 50-70 bhp depending on the specifics of the tune and the car’s condition.

This upgrade doesn’t require any significant hardware changes and can be completed fairly quickly, making it an ideal first step for anyone looking to improve their vehicle’s performance.

Performance Air Filter
While it may seem like a minor upgrade, a performance air filter can improve airflow to the engine, helping it breathe more freely. This can result in small gains in power and efficiency, along with a more pronounced intake sound. It’s a simple modification, but one that complements the Stage 1 tune well.

GPF-Back Exhaust
For those looking for a more aggressive exhaust note, a GPF-back exhaust system is a good option. The GPF (Gasoline Particulate Filter) in modern cars helps reduce emissions but can also stifle the engine’s sound. A GPF-back exhaust replaces the section of the exhaust after the GPF, enhancing the tone of the car without sacrificing performance. While it may not add significant power, it will certainly make the car sound more engaging, which is one of the main reasons owners opt for this modification.

Check out our range of intake options for your B9 RS model here

Check out our exhaust range for your RS4/RS5 here

Stage 2 Tuning: Enhanced Performance with Cooling and Exhaust Modifications

Stage 2 tuning takes things a step further and requires more significant modifications to get the most out of the performance potential of your RS4 or RS5.

Downpipe
One of the key upgrades in Stage 2 tuning is the downpipe. Replacing the stock downpipe with a performance version can improve exhaust flow, reduce turbo lag, and increase power. Stage 2 downpipes often feature larger diameters and smoother bends to ensure the exhaust gases are expelled as efficiently as possible. This upgrade typically gives a noticeable increase in performance, especially when paired with an ECU tune.

Cooling Modifications
As power increases, so does heat, which is why upgrading the car’s cooling system is important for Stage 2 tuning. While not strictly essential, it is highly recommended, particularly if you plan to push your car to its limits on track days or during spirited driving. Common cooling modifications include upgraded intercoolers, oil coolers, and larger radiator systems. These parts help maintain optimal operating temperatures, which improves both performance and longevity of the engine components.

At Stage 2, the combination of the ECU tune, downpipe, and cooling upgrades will result in a noticeable increase in both power and driving experience. Depending on the modifications and tuning, you can expect gains of 80-100 bhp or more, as well as a sharper throttle response and more aggressive turbo noises.

Check out RS5/RS4 cooling parts here

Check out the downpipe options here

Other Considerations

While Stage 1 and Stage 2 are the primary paths for tuning the RS4 and RS5 B9, there are other modifications worth considering, depending on your goals.

• Suspension: Upgrading to a performance suspension kit can improve handling and cornering, particularly if you plan to use the car for track days or more spirited driving.
• Brakes: A larger, more capable brake system can help improve stopping power, especially if you’ve increased the car’s performance with tuning.
• Wheels and Tyres: Lightweight wheels and performance tyres can reduce unsprung weight and improve grip, which will further enhance the overall driving experience.

Click here to view our range of brake options for your RS4/RS5

You can also find an extensive list of suspension modifications here!

Conclusion

Tuning the Audi RS4 or RS5 B9 can be a rewarding experience, whether you’re after more power, better sound, or a more engaging driving experience. For many owners, starting with simple upgrades like an ECU tune, performance air filter, or GPF-back exhaust will be sufficient to enjoy the benefits of tuning. However, for those looking for more significant performance gains, Stage 2 modifications like a downpipe and enhanced cooling will unlock the car’s full potential.

Remember that tuning your car is a personal choice, and there’s no one-size-fits-all approach. It's important to consider what you want from the vehicle and what fits your driving style before making any decisions. Always ensure that any modifications are done by reputable professionals and that the parts you choose are compatible with your car’s specifications.