BMW B58 Gen 2 G-Series M340i/M440i/M240i Catless/Catted Downpipe With Heat Shield

BMW B58 Gen 2 G-Series M340i/M440i/M240i Catless/Catted Downpipe with Heat Shield

Unlock the full performance potential of your BMW B58TU-powered G-Series platform with these Catless or High-Flow Catted Downpipes featuring integrated thermal heat shielding — engineered to maximise exhaust flow, improve turbocharger efficiency, and unleash the true sound of BMW's legendary turbocharged inline-six.

Designed specifically for the B58 Gen 2 (B58TU) engine, these high-flow downpipes replace the restrictive factory catalytic converter, significantly reducing exhaust backpressure and allowing the turbocharger to spool faster and operate more efficiently. Available in both Catless and High-Flow Catted configurations, these downpipes deliver improved throttle response, increased power potential, enhanced turbo acoustics, and a noticeably more aggressive exhaust note.

Constructed from premium 304 stainless steel and wrapped in high-temperature thermal heat shielding, these downpipes help reduce engine bay temperatures while protecting surrounding components from excessive radiant heat. Precision TIG welding and mandrel-bent construction ensure exceptional durability and long-term reliability under demanding performance conditions.

Whether paired with the factory exhaust system or a complete aftermarket setup, these downpipes provide one of the most effective performance upgrades available for the B58TU platform.

Key Features

Catless or High-Flow Catted Configurations

Available in either Catless form for maximum exhaust flow and performance, or with a high-flow catalytic converter for a more emissions-friendly setup and refined sound characteristics.

Integrated Thermal Heat Shielding

Helps reduce radiant heat and protects surrounding engine bay components from excessive temperatures.

Premium 304 Stainless Steel Construction

Manufactured from corrosion-resistant stainless steel for exceptional durability and heat resistance.

Improved Turbo Efficiency

Reduced exhaust backpressure allows the turbocharger to spool faster and operate more efficiently.

Mandrel-Bent Tubing

Maintains unrestricted exhaust flow and consistent pipe diameter throughout the system.

Precision TIG Welded

Strong, clean welds engineered to withstand extreme temperatures and demanding performance applications.

Direct Bolt-On Fitment

Designed specifically for BMW B58 Gen 2 (B58TU) G-Series vehicles using factory mounting locations.

Performance Benefits (When Tuned)

• Increased horsepower and torque potential
• Faster turbo spool and improved throttle response
• Reduced exhaust backpressure
• Enhanced turbocharger efficiency
• Increased turbo whistle and induction acoustics
• More aggressive exhaust note
• Ideal foundation for Stage 1, Stage 2, and higher-performance builds

Performance gains may vary depending on ECU calibration, fuel quality, and supporting modifications.

Sound Characteristics

Catless Version

• Deeper and more aggressive exhaust tone
• Increased turbo spool and whistle acoustics
• Louder cold starts
• Enhanced pops and burbles (when tuned)
• Maximum exhaust flow and sound

High-Flow Catted Version

• Sportier and more refined exhaust note
• Increased turbo spool acoustics
• Improved exhaust volume without excessive harshness
• Excellent balance between performance and everyday drivability

Vehicle Fitment

BMW G20/G21 M340i xDrive (2019+)
BMW G22/G23/G26 M440i xDrive (2021+)
BMW G42 M240i xDrive (2022+)
BMW G29 Z4 M40i (2019+)

3.0L Turbocharged B58 Gen 2 (B58TU) Engine

Please Note

Professional installation is strongly recommended.

Performance gains will vary depending on vehicle condition, fuel quality, ECU calibration, and supporting modifications.

The Catless version is intended for off-road and motorsport use only.

Vehicles equipped with OPF/GPF emissions systems may require alternative configurations.

Why Choose Proven Performance Parts

We specialise in high-performance parts for European vehicles — including Volkswagen GTI & R models, Audi S/RS platforms, and BMW M vehicles. Every product we offer is carefully selected for its quality, fitment, and real-world performance — tested by enthusiasts, for enthusiasts.