Supersprint B58 100 Cell High-Flow Catted Downpipe / Sport Catalyst Front Pipe for BMW 40i & M40i (M240i 340i 440i 540i 640i 740i X3/X4 M40i) Direct-Fit Performance Catalytic Converter | WRC 100 CPSI | PN 524221

Supersprint B58 100 Cell Sport Catalyst Front Section - PN 524221

Transform your BMW turbo six with the Supersprint WRC 100 CPSI sport catalyst for the B58 engine. This front catalyst section is a direct bolt-on that replaces the restrictive primary cat, cutting backpressure and unlocking sharper boost response, a stronger mid-range and a deeper, more purposeful tone. It keeps all factory mounting points, heatshield locations and sensor provisions for an OE-style install with no cutting or welding.

At the heart of this assembly is a large-volume, 100 cell metallic substrate with a generous precious metal loading for excellent flow and stable emissions behaviour. The precise lambda sensor bosses and robust flex section ensure durability and correct engine movement, helping to minimise the risk of warning lights and the unwanted odours often associated with inferior catalysts.

We have installed and run this Supersprint unit on our own projects and customer cars. Feedback is consistently positive - faster spool, smoother power delivery and a quality sound when paired with suitable software. It is the key hardware upgrade for B58 tuning plans from mild remaps to more aggressive Stage 2 packages.

Highlights

• Direct-fit sport catalyst front pipe - simple swap for the OEM primary catalyst
• 100 CPSI metallic honeycomb core with high noble metal content for superior flow
• Optimised, large-volume body to reduce backpressure and aid turbo efficiency
• Factory-position oxygen sensor bungs and heatshield provisions
• Heavy-duty flex joint for longevity and correct drivetrain movement
• Designed to help reduce the chance of CEL issues seen with low grade cats
• Perfect pairing with ECU calibration on B58-powered models
• Supersprint quality, fit and finish you can trust

Fitment - BMW B58 applications

• 2 Series F22 LCI M240i, F23 M240i including xDrive
• 3 Series F30 F31 LCI 340i including xDrive, F34 GT 340i
• 4 Series F32 F33 F36 LCI 440i including xDrive
• 5 Series G30 540i, G30 540i xDrive, G31 Touring 540i xDrive, G38 540Li
• 6 Series G32 GT 640i, G32 GT 640i xDrive
• 7 Series G11 740i, G12 740Li, G12 740Li xDrive
• X Models G01 X3 M40i xDrive, G02 X4 M40i xDrive

Part number

Supersprint 524221

Installation and support

Professional fitting recommended. For installation, mapping advice and package deals, contact MJ Modifications in Warwickshire for a quote - info@mjmodifications.co.uk.

What owners notice

• Quicker turbo response and stronger in-gear acceleration
• Enhanced exhaust character under load while remaining refined at cruise
• Consistent fitment - retains factory hardware and locations

Compatibility notes

Suits B58-powered BMW 40i and M40i models listed above. Designed as a direct replacement for the stock primary catalytic converter and to work with OE or performance cat-back systems.

Search terms to help you find this item

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Manufacturer and warranty

Manufactured by Supersprint

Supersprint one year warranty