BMW B58 Gen 2 G-Series M340i/M440i/M240i Catless Downpipe

BMW B58 Gen 2 G-Series M340i/M440i/M240i Catless Downpipe

Unlock the full performance potential of your BMW B58TU-powered G-Series platform with this high-flow Catless Downpipe — 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, this catless downpipe replaces the restrictive factory catalytic converter, significantly reducing exhaust backpressure and allowing the turbocharger to spool faster and operate more efficiently. The result is sharper throttle response, increased power potential, enhanced turbo acoustics, and a noticeably more aggressive exhaust note.

Manufactured from premium mandrel-bent 304 stainless steel and precision TIG welded throughout, this downpipe is built to withstand extreme temperatures and demanding performance applications while maintaining OEM-style fitment and reliability.

Whether paired with the factory exhaust system or a complete aftermarket setup, this catless downpipe provides one of the most effective performance upgrades available for the B58TU platform.

Key Features

High-Flow Catless Design

Removes the restrictive factory catalytic converter for maximum exhaust flow and performance potential.

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 2 and higher-performance builds

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

Sound Characteristics

Compared to the factory downpipe, this catless downpipe typically delivers:

• Deeper and more aggressive exhaust tone
• Increased turbo spool and whistle acoustics
• Louder cold starts
• Enhanced pops and burbles (when tuned)
• Greater overall exhaust volume
• Improved exhaust character throughout the rev range

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

This is a catless motorsport product intended for off-road and motorsport use only.

Professional installation is strongly recommended.

ECU tuning may be required to fully utilise the performance benefits and prevent potential check engine lights associated with catalyst removal.

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.