Description
Designed for the McLaren 720S 4.0T twin-turbocharged V8, the Untd. Performance Catless Downpipe W/ Heat Shield is an ideal upgrade for enthusiasts looking to reduce exhaust restriction, improve turbocharger response, increase horsepower potential, and unleash a more aggressive version of the M840T V8 sound.
By removing the restrictive factory catalytic converters and providing a significantly freer-flowing exhaust path from the twin turbochargers, the Untd. Performance Catless Downpipes help reduce exhaust backpressure and allow the 4.0T V8 to evacuate exhaust gases more efficiently. The integrated heat shields also help manage radiant exhaust heat within the engine bay, making this setup well suited for high-performance and tuned applications.
Key Features
Catless Design – Maximum Exhaust Flow:
The Untd. Performance Catless Downpipes eliminate the restrictive factory catalytic converters, creating a significantly freer-flowing exhaust path from the twin turbochargers. Reduced exhaust restriction helps minimize backpressure and allows the M840T engine to move exhaust gases more efficiently.
Integrated Heat Shield – Improved Heat Management:
The included heat shields help reduce radiant heat transfer from the high-temperature downpipes into the surrounding engine bay. This provides additional thermal protection for nearby components while maintaining the high-flow benefits of the catless downpipe design.
Improved Turbo Response & Performance:
The freer-flowing design allows the twin-turbocharged 4.0T V8 to expel exhaust gases more efficiently. Reduced backpressure can help improve turbocharger response, throttle response, horsepower, and torque, particularly when combined with an appropriate ECU calibration.
Aggressive McLaren V8 Sound:
The catless design significantly enhances the character of the M840T engine, producing a deeper, louder, and more aggressive exhaust tone. Turbocharger spool and exhaust volume become more pronounced under acceleration.
Designed for the M840T 4.0T V8:
Engineered specifically for the McLaren 720S 4.0T twin-turbocharged V8, providing a high-flow replacement for the factory downpipe configuration.
Durable Performance Construction:
Built to withstand the extreme exhaust temperatures, pressure, vibration, and demanding conditions generated by the high-output M840T engine. Precision-welded construction is designed for dependable performance in demanding applications.
Direct-Fit Design:
Designed specifically for compatible McLaren 720S 2017+ applications, providing a replacement for the factory downpipe configuration and allowing compatibility with suitable OEM and aftermarket exhaust components.
Installation Hardware Included:
The downpipes include the necessary clamps, bolts, and required installation hardware where applicable to help ensure a secure installation and proper sealing.
Tune Recommended / Required for Optimal Performance:
An ECU tune is strongly recommended and may be required when installing catless downpipes. Proper calibration allows the M840T to take advantage of the increased exhaust flow while optimizing boost control, ignition timing, fueling, 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 McLaren 720S may see significant horsepower and torque gains from the reduced exhaust restriction.
For the McLaren M840T 4.0T platform, the largest gains are generally achieved when the catless downpipes are combined with an appropriate Stage 2 / downpipe-specific ECU calibration designed to take advantage of the increased exhaust flow. The calibration may also require rear-O2 / catalyst monitoring to be disabled following removal of the factory catalytic converters.
| Configuration | Estimated HP Gain | Estimated Output |
|---|---|---|
| Stock Tune | ~10–20 HP | ~720–730 HP* |
| Stage 1 Tune | ~80–110 HP | ~790–820 HP* |
| Stage 2 / Downpipe-Specific Tune | ~130–160 HP | ~840–870 HP* |
Figures are estimated crank horsepower based on a 710 HP McLaren 720S reference configuration, 91–93 octane (95–98 RON) pump fuel, and stock turbochargers. Actual results will vary depending on ECU calibration, fuel quality, engine condition, supporting modifications, and dyno methodology.
For reference, published tuning data for the 720S has reported substantial gains from ECU calibration, including approximately +80 PS at Stage 1 and +130 PS at Stage 2 with 200-cell sport catalytic converters. Catless configurations and individual vehicles may produce different results.
⚠️ Check Engine Light Warning
A Check Engine Light (CEL) is expected after installing catless downpipes with the factory ECU calibration due to the removal of the factory catalytic converters and the resulting change in exhaust emissions readings.
A compatible ECU tune is strongly recommended and may be required to properly calibrate the vehicle after installation and address catalyst-efficiency-related fault codes.
A downpipe-specific Stage 2 calibration may require rear-O2 / catalyst monitoring to be disabled for proper operation following removal of the factory catalytic converters.
Tune requirements can vary depending on model year, ECU software, emissions equipment, and existing modifications.
For optimal performance, drivability, and compatibility, professional ECU tuning is recommended.
Why Upgrade?
The factory downpipes and catalytic converters are designed primarily around emissions control, noise requirements, and factory operating specifications. These components can create additional exhaust restriction, particularly as turbocharger airflow and boost pressure increase.
The Untd. Performance Catless Downpipes W/ Heat Shield replace the restrictive factory configuration with a significantly freer-flowing exhaust path from the M840T’s twin turbochargers.
The integrated heat shields provide an additional layer of thermal management within the engine bay, helping reduce radiant heat exposure to surrounding components while maintaining the performance benefits of the catless downpipe design.
When combined with an appropriate ECU tune and supporting modifications, these downpipes provide a strong foundation for extracting additional performance from the McLaren 720S 4.0T twin-turbocharged V8.
Compatibility
- McLaren 720S – 2017+
- McLaren 720S 4.0T Twin-Turbo V8
- McLaren M840T 4.0T V8
- McLaren 720S Coupe
- McLaren 720S Spider
Fitment may vary depending on model year, engine configuration, ECU software, emissions equipment, and existing exhaust modifications. Please verify compatibility before ordering.
⚠️ Important Notice
CATLESS / OFF-ROAD 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.
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.
