Description
Designed for the Audi RS6 and RS7 C8 equipped with the 4.0 TFSI EA825 V8, the Untd. Performance Catless Downpipe is engineered for enthusiasts looking to reduce exhaust restriction, improve turbocharger response, increase horsepower and torque potential, and unlock a more aggressive exhaust note from the twin-turbocharged 4.0T platform.
Featuring a high-flow catless design, this downpipe provides a significantly less restrictive exhaust path compared to the factory catalytic converter assembly. When combined with the appropriate ECU calibration, the increased exhaust flow allows the EA825 turbochargers to operate more efficiently while supporting higher power levels.
Key Features
- Catless Design – Maximum Exhaust Flow:
The Untd. Performance Catless Downpipe removes the restrictive factory catalytic converter to maximize exhaust flow and minimize backpressure after the turbochargers. The freer-flowing design helps the 4.0 TFSI expel exhaust gases more efficiently. - Improved Turbo Response & Performance:
The reduced exhaust restriction can help improve turbocharger response and exhaust gas flow. When paired with an appropriate ECU tune and supporting modifications, the downpipe can contribute to improved throttle response, horsepower, and torque. - Aggressive 4.0T V8 Sound:
Removing the factory catalytic converter significantly enhances the character of the 4.0 TFSI twin-turbo V8, producing a deeper, louder, and more aggressive exhaust tone. Turbocharger spool and exhaust notes become more pronounced under acceleration. - Durable Construction:
Built to withstand the extreme exhaust temperatures, pressure, and demanding conditions generated by the EA825 V8. Precision-welded construction provides dependable performance for high-performance and competition-oriented applications. - Direct-Fit Design:
Engineered specifically for the Audi C8 RS6 and RS7 4.0T EA825, providing a direct replacement for the factory downpipe and designed to work with suitable OEM and aftermarket exhaust components. - Installation Hardware Included:
The downpipe includes replacement gaskets, bolts, and required installation hardware to help ensure a proper fit and secure installation. Supplied hardware helps simplify installation while providing the necessary components for proper sealing and mounting. - Tune Recommended / Required for Optimal Performance:
An ECU tune is strongly recommended and may be required when installing a catless downpipe. Proper calibration allows the EA825 and turbochargers to take full advantage of the increased exhaust flow while optimizing boost control, fueling, ignition timing, throttle response, and overall performance.
Estimated Performance Gain
Actual results will vary depending on ECU calibration, fuel quality, vehicle condition, supporting modifications, and dyno methodology. The following figures are estimated crank horsepower and torque gains based on the 591 HP factory-rated Audi RS6/RS7 C8, using 91–93 octane (95–98 RON) pump fuel and stock turbochargers.
| Tuning Level | Estimated HP Gain | Estimated Output |
|---|---|---|
| Stock Tune | ~8–15 HP | ~599–606 HP |
| Stage 1 Tune | ~95–130 HP | ~686–721 HP |
| Stage 2 / Downpipe-Specific Tune | ~115–155 HP+ | ~706–746 HP |
Estimated Torque Gain: Approximately +10–20 WTQ on the stock calibration, +100–150 WTQ with Stage 1 software, and +120–180 WTQ with a downpipe-specific Stage 2 calibration. Actual torque output varies significantly depending on ECU/TCU calibration, fuel, boost targets, supporting modifications, and dyno methodology.
Stock Tune: A catless downpipe can reduce exhaust backpressure and provide slightly quicker turbo spool, but the factory ECU calibration will not fully utilize the additional exhaust flow. A Check Engine Light is expected due to catalyst-efficiency/rear-O2 monitoring, and a reduced-power/protection mode may occur on this platform.
Stage 1 Tune: An ECU remap optimized for the factory hardware can produce approximately 686–721 HP. The downpipe is not required to achieve the Stage 1 power level, as the primary gains come from the ECU calibration.
Stage 2 / Downpipe-Specific Tune: Combining the Untd. Performance Catless Downpipe with a dedicated Stage 2 ECU calibration can produce approximately 706–746 HP. This represents the largest estimated gain of the configurations listed above, with the tune specifically calibrated to take advantage of the freer-flowing downpipe.
Performance figures are platform estimates based on typical published tuner figures and are not re-verified dyno results for this specific product.
⚠️ Check Engine Light Warning
Because this product removes the factory catalytic converter, installing a catless downpipe can trigger a Check Engine Light (CEL) due to catalyst-efficiency and rear-O2 sensor monitoring.
A properly calibrated ECU tune may be required to address catalyst monitoring and allow the engine management system to operate correctly with the modified exhaust system.
On the Audi C8 RS6/RS7 EA825 platform, a catless downpipe installed without the appropriate calibration may also result in a reduced-power or protection mode.
Why Upgrade?
The factory catalytic converter is designed primarily around emissions compliance, noise reduction, and OEM operating requirements. Replacing it with a freer-flowing catless downpipe reduces restriction directly after the twin turbochargers and improves the efficiency of the exhaust path.
The result is improved exhaust gas flow, reduced backpressure, sharper turbo response, a more aggressive V8 exhaust note, and increased power potential when paired with the appropriate ECU calibration.
For enthusiasts running a Stage 2 performance tune, the downpipe becomes an important supporting modification that allows the calibration to take advantage of the increased exhaust flow.
Compatibility
- Audi RS6 C8 – 4.0 TFSI EA825 – 591 HP
- Audi RS7 C8 – 4.0 TFSI EA825 – 591 HP
- Audi RS6 Avant C8 – 4.0T twin-turbo V8
- Audi RS7 Sportback C8 – 4.0T twin-turbo V8
- Designed for Audi 4.0 TFSI EA825 configurations
- Compatible with suitable OEM and aftermarket exhaust systems
⚠️ Important Notice
- CATLESS / OFF-ROAD / COMPETITION USE ONLY
- Removing the catalytic converter may cause a Check Engine Light and may result in a reduced-power/protection mode without appropriate ECU calibration.
- An ECU tune is strongly recommended and may be required for optimal performance and proper catalyst-monitoring calibration.
- The Stage 2 configuration requires a downpipe-specific ECU calibration.
- This product is intended for off-road, track, racing, and competition applications only.
- Catless exhaust components may not comply with federal, provincial/state, or local emissions regulations and may not be legal for use on public roads in Canada or the United States.
- Estimated horsepower and torque figures are provided for reference only. Actual results vary based on fuel quality, ECU calibration, supporting modifications, engine condition, turbocharger condition, drivetrain losses, and testing methodology.
- Professional installation and ECU calibration are recommended.
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