Audi RS6 C8 Downpipes: Catless and Catted Options Explained

The Audi RS6 C8 is a performance powerhouse that perfectly balances everyday practicality with supercar-level speed. One of the most popular upgrades for RS6 owners is replacing the factory downpipes. Whether you’re aiming for a more aggressive sound, faster turbo spool, or additional horsepower, upgrading to catless or catted downpipes can significantly transform your driving experience. In this article, we’ll explore both options, their pros and cons, and help you decide which is best for your build.

What Are Downpipes?

Downpipes are a crucial part of a turbocharged vehicle’s exhaust system. They connect the turbocharger to the rest of the exhaust, and their design heavily impacts performance, sound, and emissions. The stock Audi RS6 C8 downpipes typically have restrictive catalytic converters that prioritize emissions control over maximum performance.

Upgrading to aftermarket downpipes can reduce backpressure, improve exhaust flow, and unlock substantial performance gains.

Catless Downpipes: Maximum Performance

Catless downpipes eliminate the catalytic converters, offering a free-flowing exhaust path. This leads to noticeable benefits such as:

• Increased Horsepower and Torque: With less restriction, the turbochargers can spool faster, resulting in quicker throttle response and more power.
• Enhanced Turbo Sound: Catless downpipes produce a louder, more aggressive exhaust note, with pronounced turbo whistle and crackles.
• Lower Exhaust Temperatures: Improved flow helps reduce heat buildup around the turbo.

Pros of Catless Downpipes:

• Maximum performance potential.
• Aggressive, motorsport-like sound.
• Reduced turbo lag.

Cons of Catless Downpipes:

• May trigger a check engine light (CEL) due to emissions sensors.
• Not street legal in many regions.
• Can produce strong exhaust odors.

For track cars or owners who prioritize performance over street legality, catless downpipes are often the preferred choice.

Catted Downpipes: Balanced Performance and Compliance

Catted downpipes include high-flow catalytic converters that still reduce emissions but with much less restriction compared to the factory setup. These downpipes offer a great middle ground.

Pros of Catted Downpipes:

• Increased horsepower without violating most emissions regulations.
• Minimal chance of triggering a CEL when using proper tuning.
• More refined sound compared to catless, but still deeper and sportier than stock.
• Often street legal, depending on local laws.

Cons of Catted Downpipes:

• Slightly less power compared to catless options.
• Typically more expensive than catless alternatives.

For drivers who use their Audi RS6 C8 on public roads but still want better performance and sound, catted downpipes are usually the smarter option.

Installation and Tuning Considerations

When installing either catless or catted downpipes, it is highly recommended to pair them with ECU tuning. Without proper tuning, you may experience check engine lights, poor drivability, or fail emissions tests.

Tuning ensures:

• Optimized air-fuel ratios.
• Correct sensor readings.
• Maximum safe power gains.

Additionally, installing aftermarket downpipes often requires supporting mods like upgraded exhaust systems or intercoolers to fully capitalize on the performance increase.

Sound Differences: Catless vs. Catted

One of the most immediate changes after a downpipe upgrade is the sound. Catless downpipes offer a raw, aggressive tone that is significantly louder, especially under throttle. The sound is sharper, with noticeable turbo whistle and pops.

Catted downpipes provide a more controlled exhaust note. The sound is deeper and richer, but without excessive volume or drone, making it more suitable for daily driving.

Conclusion

Upgrading the Audi RS6 C8 downpipes is one of the best modifications for enthusiasts seeking more power and a thrilling exhaust note. Catless downpipes provide unmatched performance and sound for track use but come with potential legal and comfort drawbacks. On the other hand, catted downpipes strike a balance between power gains and road legality, making them a popular choice for street-driven vehicles.