Description
Designed for Mercedes-Benz and Mercedes-AMG vehicles equipped with the 3.0L M276 V6 biturbo, the Untd. Performance Catless Downpipe is engineered for enthusiasts looking to reduce exhaust restriction, improve turbocharger response, increase horsepower and torque potential, and produce a more aggressive exhaust note.
Featuring a high-flow catless design, this downpipe removes the restrictive factory catalytic converter and creates a freer-flowing exhaust path directly after the turbochargers. When combined with the appropriate ECU calibration, the reduced exhaust restriction allows the M276 turbochargers to operate more efficiently while supporting increased 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 M276 3.0T V6 expel exhaust gases more efficiently. - Improved Turbo Response & Performance:
The high-flow design reduces exhaust restriction and can help improve turbocharger response. When paired with an appropriate ECU tune and supporting modifications, the reduced backpressure can contribute to improved throttle response, horsepower, and torque. - Aggressive M276 V6 Biturbo Sound:
The catless design enhances the character of the 3.0L M276 V6 biturbo, 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 exhaust temperatures, pressure, and demanding conditions generated by the twin-turbocharged M276 engine. Precision-welded construction provides dependable performance for both street-performance and competition-oriented applications. - Direct-Fit Design:
Engineered for compatible Mercedes-Benz and Mercedes-AMG M276 applications, 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 M276 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 362 HP factory-rated C43 W205, using 91–93 octane (95–98 RON) pump fuel and stock turbochargers.
| Tuning Level | Estimated HP Gain | Estimated Output |
|---|---|---|
| Stock Tune | ~5–15 HP | ~367–377 HP |
| Stage 1 Tune | ~50–75 HP | ~412–437 HP |
| Stage 2 / Downpipe-Specific Tune | ~70–100 HP+ | ~432–462 HP |
Estimated Torque Gain: Approximately +10–20 WTQ on the stock calibration, +60–90 WTQ with Stage 1 software, and +80–120 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.
Stage 1 Tune: An ECU remap optimized for the factory hardware can produce approximately 412–437 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 432–462 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.
Published tuner data provides additional context for the platform, with Weistec estimating approximately 5–15 HP from M276 downpipes, while other calibrations can provide substantially greater gains depending on tune, fuel, and supporting modifications.
⚠️ 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.
For the best results, the ECU calibration should be specifically designed for the combination of the M276 engine and catless downpipe.
Why Upgrade?
The factory catalytic converter is designed primarily around emissions compliance, noise reduction, and OEM operating requirements, creating additional exhaust restriction after the turbochargers. Replacing it with a freer-flowing catless downpipe reduces restriction and improves the efficiency of the exhaust path.
The result is improved exhaust gas flow, reduced backpressure, sharper turbo response, a more aggressive M276 V6 exhaust note, and greater 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
- Mercedes-AMG C43 W205 – 3.0L V6 Biturbo M276 – 362 HP
- Mercedes-Benz C400 W205 – 3.0L V6 Biturbo M276 – 329 HP
- Mercedes-Benz C450 W205 – 3.0L V6 Biturbo M276
- Mercedes-AMG C43 W205 – later 385 HP applications
- Mercedes-Benz E400 W213 – 3.0L V6 Biturbo M276
- Mercedes-AMG E43 W213 – 3.0L V6 Biturbo M276
- Mercedes-Benz C400 / C450 / C43 / E400 / E43 M276 applications
- Mercedes-Benz C238 M276 applications
- 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.
- 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.
Reviews
There are no reviews yet.