AIRTEC Motorsport High-Flow B58 De-Cat Downpipe (Decat) for BMW M140i M240i 340i 440i 540i 640i 740i X3 M40i X4 M40i - Cast Elbow, Stainless Steel, Direct Fit to OEM & Aftermarket

AIRTEC catless turbo front section for BMW B58

Free up exhaust flow on your turbocharged straight-six with this AIRTEC catless front pipe. By replacing the restrictive primary catalytic converter, it cuts back-pressure, improves turbine response and delivers a sharper throttle feel with a deeper, more purposeful soundtrack. If you want a stronger, more responsive B58, this is a proven hardware upgrade that transforms the drive.

Highlights

• Cast turbo outlet elbow maintains full internal diameter for exceptional gas speed
• Durable stainless steel construction with a quality finish
• Smooth-radius bends and uninterrupted bore to reduce restriction
• Adaptor included for a simple bolt-on connection to the factory system
• Compatible with most performance cat-back systems
• Pairs perfectly with ECU calibration for even greater results

Why we rate it

We have fitted this AIRTEC hardware on multiple B58 cars at our Warwickshire workshop and the feedback has been consistently positive. Customers report faster spool, improved drivability and a richer exhaust tone that enhances the overall experience, especially when combined with software and supporting mods.

Vehicle applications

Designed for BMW models equipped with the B58 3.0 petrol engine:

• F20 F21 1 Series 140i
• F22 F23 2 Series 240i
• F30 F31 3 Series 340i
• F32 F33 F36 4 Series 440i
• G30 G31 G38 5 Series 540i
• G32 6 Series GT 640i
• G12 7 Series 740i
• G01 X3 M40i
• G02 X4 M40i

Build details

• Cast turbine outlet section for maximum flow retention
• Stainless steel pipework for strength and longevity
• Neat welds and a tidy presentation with AIRTEC plaque
• Direct replacement for the OE front section with supplied adaptor

Fitting and support

Professional installation recommended. For expert fitting, book in with MJ Modifications in Warwickshire. Request a quote at info@mjmodifications.co.uk.

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Important information

This product removes the primary catalytic converter and is intended for motorsport and off-road use only. It will not pass a UK MOT or roadside emissions checks.