Increased Downpipe Decat – BMW M3 / M4 S58 Engine

Upgrade the performance and sound of your BMW M3 and BMW M4 equipped with the S58 engine with the InoxPower Increased Decat Downpipe. This high-flow downpipe replaces the restrictive OEM catalytic converter, dramatically improving exhaust flow, turbo efficiency and overall performance.

Compatible with:

• BMW M3 (S58 engine)

• BMW M4 (S58 engine)

Maximum Performance for the BMW S58 Engine

The downpipe—also known as a decat—installs between the turbocharger and the exhaust system. By eliminating the restrictive factory catalyst, the exhaust gases can flow faster and more freely, resulting in:

• increased horsepower and torque

• stronger and quicker throttle response

• reduced turbo back pressure

• lower exhaust gas temperatures (EGT)

On a stock engine, an open downpipe can naturally provide up to 10–12% more power.
If the ECU is remapped, the gains become even more significant, making the downpipe one of the most recommended upgrades for the S58 engine—especially when installed together with a larger turbo or stage upgrade.

Improved Turbocharger Efficiency

By reducing exhaust gas restrictions, the turbocharger works in a more efficient temperature range. Benefits include:

• lower turbo heat

• less stress on internal components

• faster turbo spool

• better long-term reliability

Aggressive, Racing Exhaust Sound

The OEM catalytic converter absorbs sound and acts as a silencer. Installing an InoxPower decat downpipe gives your M3/M4:

• a deeper, darker exhaust tone

• a more aggressive and racing-style sound

• improved character even with the OEM exhaust system

A must-have upgrade if you are looking for an authentic motorsport sound.

Handcrafted Quality – AISI 304 Stainless Steel

The InoxPower EVO-RACE Downpipes available at inoxpower.com are built using:

• AISI 304 stainless steel

• TIG welded construction

• Brushed finish for premium aesthetics

Each downpipe is designed for a perfect fit with both the OEM exhaust system and most aftermarket exhausts.
Before purchase, always check compatibility with your specific vehicle version and exhaust configuration.

Main Benefits of the InoxPower S58 Downpipe

• noticeable performance increase

• quicker engine and throttle response

• racing sound with deeper tone

• reduced turbo temperature

• optimized exhaust flow and lower back pressure

• plug-and-play fitment on M3/M4 S58

Legal Notice

This product is not approved for road use. Intended for track use only. InoxPower declines any responsibility for improper use on public roads.