CTS Turbo BMW B58 F20 F22 F30 G11 G30 4.5″ High-flow Cat (Inc. M140i, 340i, 540i & 740i)

B58 Sports Catalyst and Catted Downpipe Upgrade – 4.5 inch, Direct Fit

Unlock real performance from your B58-powered BMW with this 4.5 inch performance sports catalyst and catted downpipe. Engineered for serious flow and a sharper driving feel, it replaces the restrictive factory section with a high quality 200-cell catalyst. Expect stronger breathing, a deeper, motorsport-inspired soundtrack and a noticeable step up in performance while retaining excellent drivability.

Crafted from 304-grade stainless steel with hand TIG-welded, back-purged seams and designed using computer-aided modelling for OE-level fit, this is a true bolt-on upgrade for enthusiasts who want more from their M140i, M240i, 340i, 440i, 540i or 740i. We have fitted this unit to multiple customer cars and our own builds, and feedback has been consistently positive on quality, fitment and sound.

Why choose this B58 catted downpipe

• 4.5 inch oversized catted section for high exhaust gas velocity and reduced back pressure
• 200-cell performance catalyst for excellent flow compared with the stock part
• 304 stainless construction with precise TIG welds and back purging for durability
• Direct replacement for the OE downpipe, designed for perfect alignment and sealing
• Sporty tone under load, subtle on the motorway with the factory rear system
• Proven on road cars for everyday usability without unwanted cabin boom

Tuning and setup

To prevent a check engine light, Stage 2 calibration is required. We strongly recommend Bootmod3 Stage 2 software for correct emissions diagnostics and the best drivability.

Fitment guide

• 2016+ F20 BMW M140i
• 2016+ F22 BMW M240i and M240i xDrive
• 2016+ F30, F31, G20 BMW 340i and 340i xDrive
• 2016+ F32, F33, F36, G22, G23, G26 BMW 440i and 440i xDrive
• 2016+ G30, G31 BMW 540i and 540i xDrive
• 2016+ G11, G12 BMW 740i and 740i xDrive

Note: Compatible with models that do not have GPF or OPF.

Installation by MJ Modifications

For professional fitting and optional tuning support, book in with MJ Modifications in Warwickshire. We install these regularly and can provide a turn-key upgrade service. Request a quote at info@mjmodifications.co.uk.

Important information

• Stage 2 software is required to avoid a check engine light
• Damage caused by crackle tune use is not covered by warranty
• Only suitable for vehicles without GPF or OPF

Manufacturer and warranty

Made by CTS Turbo and supplied with a 12 month warranty against manufacturing defects. Warranty does not cover misuse, improper installation or racing related damage. Original purchaser only.

Part number

CTS-EXH-DP-0024-CAT

Common search terms

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