Audi RS4 B5 Downpipes – Catted & Decat Performance Exhaust Upgrades

Audi RS4 B5 Downpipes – Unlock the True Power of the 2.7 BiTurbo

The Audi RS4 B5, produced between 1999 and 2001, is a legendary performance machine powered by the iconic 2.7 BiTurbo V6 engine. Known for its huge tuning potential, the RS4 B5 responds exceptionally well to performance upgrades. However, the restrictive OEM downpipes limit exhaust flow and power delivery. Upgrading to a performance Audi RS4 B5 downpipe is one of the most effective modifications to improve horsepower, reduce turbo lag and enhance exhaust sound.

Why Upgrade to a Performance Audi RS4 B5 Downpipe?

The factory downpipes are designed with emissions compliance and noise control in mind, but they restrict exhaust gases and reduce turbo efficiency. Replacing them with high-flow RS4 B5 downpipes provides multiple benefits:

• Increased horsepower & torque – improved exhaust flow reduces backpressure, allowing the turbos to breathe freely.
• Faster turbo spool – enjoy sharper throttle response and stronger acceleration.
• Enhanced exhaust tone – catted downpipes provide a refined sporty sound, while decat downpipes unleash a motorsport-inspired roar.
• Lower exhaust gas temperatures – improved thermal efficiency protects the engine during high-boost conditions.
• Perfect for ECU tuning – an essential upgrade for Stage 1, Stage 2 and hybrid turbo builds.

Types of Audi RS4 B5 Downpipes

Our range of Audi RS4 B5 downpipes is designed to suit different tuning stages and driving goals:

Catted Audi RS4 B5 Downpipes

Catted downpipes integrate a high-flow sports catalytic converter that maintains emissions compliance while improving exhaust flow. Perfect for daily-driven RS4 B5 models.

Decat Audi RS4 B5 Downpipes

Decat downpipes completely remove the catalytic converters, maximizing flow and performance gains. Ideal for track-focused builds and off-road applications where emissions are not a concern.

Material Options: Stainless Steel & Titanium

The material choice directly affects durability, heat resistance and weight:

• Stainless steel downpipes – cost-effective, corrosion-resistant and suitable for most performance builds.
• Titanium downpipes – ultra-lightweight with superior heat dissipation and a premium motorsport finish.

Performance Gains with Audi RS4 B5 Downpipes

Installing a performance RS4 B5 downpipe results in substantial improvements, especially when combined with ECU tuning:

• +20–40 HP with downpipes only.
• +50–80 HP when paired with Stage 2 ECU remapping.
• Increased torque delivery for stronger mid-range performance.
• Reduced turbo lag and sharper throttle response.

Choosing the Right Diameter

The optimal downpipe diameter depends on your build and power goals:

• 2.75-inch downpipes – perfect for mildly tuned Stage 1 setups.
• 3-inch downpipes – ideal for Stage 2 and hybrid turbo applications.
• 3.5-inch downpipes – recommended for big turbo conversions and extreme power builds.

All Audi RS4 B5 downpipes are designed for direct bolt-on installation without cutting or welding, ensuring a perfect fit every time.

Build Quality & Engineering

Our performance Audi RS4 B5 downpipes are built to the highest standards using motorsport-grade materials:

• Mandrel-bent tubing for smooth, unrestricted exhaust flow.
• Precision TIG welding for maximum strength and durability.
• OEM-style flanges and fittings for seamless integration.
• High-quality gaskets and mounting hardware included for easy installation.

Tuning Potential

Pairing a high-flow RS4 B5 downpipe with ECU tuning unlocks the full potential of the 2.7 BiTurbo engine:

• Optimized fueling and boost control for maximum gains.
• Custom exhaust tone profiles depending on catted or decat setup.
• Support for advanced configurations, including hybrid turbos, ethanol blends and big turbo conversions.

Recommended Upgrades

For the best results, combine your Audi RS4 B5 downpipe with supporting performance upgrades:

• Turbo gaskets
• Mounting flanges
• Blow-off valves
• Performance intercoolers
• ECU tuning solutions

Conclusion

Upgrading to a performance Audi RS4 B5 downpipe is one of the most effective modifications for unlocking hidden horsepower, improving turbo efficiency and enhancing your exhaust sound. Whether you choose a catted or decat downpipe, our selection guarantees premium build quality, perfect fitment and proven performance gains. Take your RS4 B5 to the next level today.