Description
Designed for the Porsche 911 991.2 3.0T flat-six platforms, the Untd. Performance Catless Downpipe is an ideal upgrade for enthusiasts looking to reduce exhaust restriction, improve turbocharger response, increase horsepower potential, and unleash a more aggressive version of Porsche’s twin-turbocharged flat-six sound.
By removing the restrictive factory catalytic converter and providing a freer-flowing exhaust path from the turbocharger, the Untd. Performance Catless Downpipe helps reduce exhaust backpressure and allows the turbocharged 3.0T H6 engine to expel exhaust gases more efficiently.
Key Features
Catless Design – Maximum Exhaust Flow:
The Untd. Performance Catless Downpipe eliminates the restrictive factory catalytic converter, creating a significantly freer-flowing exhaust path from the turbocharger. Reduced exhaust restriction helps minimize backpressure and allows the turbocharged flat-six engine to move exhaust gases more efficiently.
Improved Turbo Response & Performance:
The freer-flowing design allows the twin-turbocharged 3.0T engine to expel exhaust gases more efficiently. When paired with an appropriate ECU tune and supporting modifications, reduced restriction can help improve turbo response, throttle response, horsepower, and torque.
Aggressive Porsche Flat-Six Sound:
The catless design enhances the character of Porsche’s turbocharged flat-six engine, 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 high temperatures, exhaust pressure, and demanding conditions generated by the turbocharged Porsche H6 engine. Precision-welded construction provides dependable performance for both street-performance and competition-oriented applications.
Direct-Fit Design:
Engineered specifically for compatible Porsche 911 991.2 3.0T applications, providing a direct replacement for the factory downpipe configuration and designed to work with suitable OEM and aftermarket exhaust components.
Installation Hardware Included:
The downpipes include 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 catless downpipes. Proper calibration allows the turbocharged 3.0T engine to take full advantage of the increased exhaust flow while optimizing boost control, fueling, ignition timing, throttle response, and overall performance.
Estimated Performance Gain
Depending on the ECU calibration, fuel quality, exhaust system, turbocharger configuration, and supporting modifications, a properly tuned vehicle may see meaningful horsepower and torque gains from the reduced exhaust restriction.
For the Porsche 911 3.0T H6 platform, the largest gains are expected when the catless downpipes are paired with an appropriate performance ECU calibration. The reduced exhaust restriction allows the turbochargers to operate more efficiently and provides additional exhaust-flow capacity for tuned applications.
| Tuning Level | Estimated HP Gain | Estimated Torque Gain |
|---|---|---|
| Stock Tune | ~5–15 HP | ~10–20 WTQ |
| Stage 1 Tune | ~30–50 HP | ~40–60 WTQ |
| Stage 2 / Downpipe-Specific Tune | ~50–75 HP | ~65–90 WTQ |
Figures are general performance estimates based on stock turbochargers and pump fuel. Actual results will vary depending on the specific 911 model, factory power level, ECU calibration, fuel quality, exhaust system, supporting modifications, engine condition, and dyno methodology.
The largest gains are generally realized when the downpipes are combined with a downpipe-specific ECU calibration designed to take advantage of the increased exhaust flow.
⚠️ Check Engine Light Warning
A Check Engine Light (CEL) may occur after installing these catless downpipes due to the removal of the factory catalytic converters and the resulting change in exhaust emissions readings.
A compatible ECU tune is recommended and may be required to properly calibrate the vehicle after installation and address catalyst-efficiency-related fault codes.
Depending on the tuning solution, rear-O2 / catalyst monitoring may need to be addressed through the ECU calibration.
For optimal performance, drivability, and compatibility, professional ECU tuning is recommended.
Why Upgrade?
The factory downpipe and catalytic converter configuration is designed primarily around emissions control and factory operating requirements. These components can create additional restriction in the exhaust system, particularly as engine power and turbocharger airflow increase.
The Untd. Performance Catless Downpipe provides a significantly freer-flowing exhaust path from the turbochargers, helping reduce exhaust backpressure and improve exhaust gas evacuation.
When combined with an appropriate ECU tune, upgraded exhaust components, and supporting modifications, the downpipes can provide an excellent foundation for extracting additional performance from the Porsche 911 3.0T twin-turbocharged flat-six engine.
Compatibility
- Porsche 911 991.2 – 3.0T H6 2016+
- Porsche 911 3.0T Twin-Turbocharged Flat-Six Applications
- Compatible Porsche 911 3.0T Turbocharged Applications
Fitment may vary depending on model year, exact 911 variant, drivetrain, transmission, emissions equipment, ECU software, and existing exhaust modifications. Please verify compatibility before ordering.
⚠️ Important Notice
CATLESS / OFF-ROAD / COMPETITION USE ONLY: This product eliminates the factory catalytic converters and may not be legal for use on public roads in your jurisdiction. Check your local emissions, inspection, and vehicle regulations before installation.
A Check Engine Light may occur without appropriate ECU calibration. A compatible tune may be required for proper operation and optimal performance.
TUNE REQUIREMENT: A compatible ECU calibration is strongly recommended to take full advantage of the increased exhaust flow and available performance potential.
PERFORMANCE GAINS ARE ESTIMATES: Actual horsepower and torque gains will vary depending on turbocharger configuration, ECU calibration, fuel quality, supporting modifications, engine condition, and dyno conditions.
Professional installation and ECU calibration are recommended.
Untd. Performance is not responsible for emissions compliance, inspection requirements, or the legality of installing or operating this product on public roads.
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