4.5 inch Decat for B58 BMW

Catless 4.5 inch turbo downpipe upgrade for BMW B58

Unlock serious performance with this 4.5 inch high-flow catless downpipe for the BMW B58 turbocharged engine. By removing the factory catalytic restriction, exhaust gases move freely for quicker boost response, stronger mid-range pull and a more aggressive exhaust tone. Built from quality stainless steel for durability and heat resistance, this race downpipe is a proven upgrade for enthusiasts who want sharper throttle response and a harder-hitting soundtrack.

• Large 4.5 inch outlet size for maximum gas velocity and improved turbo efficiency
• Catless straight-through design for reduced restriction and faster boost build
• Stainless steel construction for longevity and corrosion resistance
• Enhances exhaust note with a deeper, more purposeful sound
• Ideal foundation for performance tuning and track-focused builds

Compatibility

For BMW models equipped with the B58 engine, including:

• M140i
• M240i
• 340i
• 440i

Why choose MJ Modifications

We have installed this B58 turbo downpipe on our own cars and customer builds, and the transformation in response and sound is excellent. Customers consistently praise the quality and the driving feel it delivers.

Fitting and support

Professional installation available at MJ Modifications in Warwickshire. Request a fitting quote at info@mjmodifications.co.uk.

Notes

4.5 inch equals approximately 114 mm. For motorsport or off-road use only where applicable. Please check local regulations before purchase.

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