Performance Catless Downpipes for Audi RS4 / RS5 (2018–2022) Backpressure Reduction, Speeds Gas Exhaust Properly 

These catless downpipes are designed to replace the factory catalytic converter downpipe assembly on 2018–2022 Audi RS4 and RS5 models equipped with the 2.9L twin-turbocharged V6 engine. The system eliminates the restrictive factory catalytic converters, creating an unrestricted exhaust path that reduces backpressure and improves exhaust gas velocity. This results in faster turbo spool, reduced turbo lag, enhanced throttle response, and increased exhaust flow throughout the RPM range.

The downpipes use larger diameter piping compared to the factory assembly, allowing exhaust gases to exit more efficiently. The removal of catalytic converters significantly reduces restriction in the exhaust system, which improves turbo efficiency and power delivery. The system produces a more audible exhaust note with increased turbo sound and aggressive exhaust character during acceleration and deceleration.

Vehicle Fitment

• 2018–2022 Audi RS4 Avant (2.9L Twin-Turbo V6)
• 2018–2022 Audi RS5 Coupe (2.9L Twin-Turbo V6)
• 2018–2022 Audi RS5 Sportback (2.9L Twin-Turbo V6)

Performance & Design

The system is engineered to reduce exhaust backpressure by eliminating the factory catalytic converters and using larger diameter tubing. This allows the twin turbochargers to spool more quickly and operate more efficiently by reducing restriction in the exhaust path. The improved exhaust flow reduces turbo lag and enhances throttle response, particularly during acceleration and boost conditions.

The catless design produces a significantly more audible exhaust note compared to the factory system. The sound characteristics include increased turbo noise, deeper exhaust tone, and crackling sounds during deceleration and overrun conditions. The exhaust note is substantially louder and more aggressive than the factory configuration.

Construction & Materials

The downpipes are constructed from 304 stainless steel, which provides resistance to corrosion and heat in the exhaust environment. All tubing is mandrel-bent to maintain consistent internal diameter throughout each bend, reducing turbulence and maintaining exhaust gas velocity. Flanges are CNC-machined to ensure precise alignment with factory mounting points and provide proper sealing surfaces.

The larger diameter piping reduces restriction compared to the factory assembly while maintaining structural integrity for the exhaust system. Heat shields are included to protect surrounding components from exhaust heat, similar to the factory configuration but adapted for the modified exhaust flow characteristics.

Features & Components

• 304 stainless steel construction
• Mandrel-bent tubing for consistent flow
• CNC-machined flanges for precise fitment
• Larger diameter piping versus factory
• Eliminates factory catalytic converters
• Includes heat shields for component protection
• Reduces turbo lag and improves spool characteristics
• Significantly increases exhaust volume and tone
• Lighter weight compared to factory assembly

What's Included

• Left-side catless downpipe
• Right-side catless downpipe
• Heat shields
• Mounting hardware and gaskets

Installation

• Direct replacement for factory downpipe assembly
• Uses existing factory mounting points
• No cutting or welding required
• Professional installation recommended
• Proper torque specifications must be followed

Installation Note:
Installation requires removal of the factory catalytic converter assembly and exhaust components. Professional installation is recommended due to the complexity of exhaust work and the need for proper torque specifications. New gaskets should be used at all connection points to ensure leak-free operation.

Performance Considerations

The removal of catalytic converters will trigger check engine light codes related to emissions system monitoring. An ECU tune or flash is strongly recommended to address these codes and optimize engine performance with the modified exhaust configuration. Tuning can also unlock additional power gains by adjusting fuel delivery and ignition timing to complement the improved exhaust flow.

The weight reduction compared to the factory catalytic converter assembly contributes to improved power-to-weight ratio. The downpipes are designed to withstand high exhaust temperatures and pressures associated with turbocharged applications and performance driving conditions.

Legal Notice & Compliance

FOR OFF-ROAD AND COMPETITION USE ONLY

This product is designed for off-road and racing applications only. It is not legal for use on emissions-controlled vehicles operated on public roads. Installation removes emissions control equipment required by federal and state regulations. Installation will cause the vehicle to fail emissions testing and may violate local, state, and federal laws.

Verify all applicable regulations before purchase and installation. This product is intended for use on dedicated track vehicles, competition vehicles, or in jurisdictions where such modifications are permitted. The purchaser assumes all responsibility for compliance with applicable laws and regulations.

These catless downpipes provide significantly reduced exhaust restriction for the 2.9L twin-turbocharged V6 engine. The system requires ECU tuning for optimal operation and is designed exclusively for off-road and competition use.