Stone Exhaust High-Flow Catted Downpipe / Sport Cat Front Pipe for BMW B46D G20 G21 G22 G23 G26 G30 G01 G02 (320i 330i 420i 430i 530i X3/X4 20i/30i) OPF/GPF | Euro 6 UK MOT Friendly | No CEL | SUS304 Stainless | Performance Catalytic Converter | A224NE

Performance Sport Cat Front Pipe for BMW B46D G-Series Petrol Models

Give your 2.0 turbo BMW the response, torque and flow it deserves while keeping emissions in check. This high-efficiency sport catalyst uses Stone’s vortex-core technology to clean exhaust gases and reduce back pressure for punchier acceleration and stronger mid-range pull on OPF and GPF-equipped cars. Designed to work without dashboard warning lights on compatible vehicles and to remain MOT friendly. Part number: A224NE.

Why enthusiasts choose it

• Vortex catalytic core for serious flow with clean exhaust output on petrol particulate filter cars
• Calibrated oxygen sensor placement to maintain accurate fuelling and avoid error codes on supported setups
• Meets modern emissions standards while unlocking performance on daily-driven and tuned vehicles
• SUS304 stainless construction for longevity and corrosion resistance in UK weather
• Direct-fit front catalyst section with factory-style connections for an easy bolt-on upgrade
• Reinforced turbo flange and deep-penetration welds for reliability under high heat and boost
• Optimised tubing diameter and smooth routing to maximise turbine efficiency and reduce lag

Engineering that delivers

Developed from full 3D scans of the OEM assembly across multiple G-series platforms, the pipe geometry is refined using flow, temperature and pressure modelling to minimise restriction where it matters most. Precision CNC bending keeps the tube round through tight arcs, while accurately formed sections and robotic welding ensure repeatable fit and airtight seams.

• Multi-axis CNC mandrel bends for excellent roundness through tight 180 degree turns
• Tightly controlled manufacturing tolerances to reduce turbulence and improve gas speed
• Crisscross and overlapping TIG weld techniques for long-term strength

Vehicle fitment

For BMW B46D 2.0 turbo petrol with OPF and GPF across the following G-series chassis:

• 3 Series: G20 and G21 320i and 330i, including xDrive
• 4 Series: G22, G23 and G26 420i and 430i, including xDrive
• 5 Series: G30 530i xDrive
• SAV and SAC: G01 X3 20i and 30i, G02 X4 20i and 30i, including xDrive

Real-world results

We have supplied and installed this sport cat on multiple B46D-powered cars and the feedback is consistently positive. Owners report quicker spool, a meatier mid-range and a freer top end, with a tasteful increase in tone. The refined catalyst design keeps things civil for daily use on OPF-equipped vehicles.

Installation and support

Direct replacement for the factory front catalyst section. Professional fitting recommended. For installation, book with MJ Modifications in Warwickshire. Request a quote at info@mjmodifications.co.uk.

Specifications

• Material: SUS304 stainless steel
• Emissions: Euro 6 friendly design for OPF and GPF cars
• Electronics: Designed to run without dash warnings on compatible vehicles
• Part number: A224NE
• Manufacturer: Stone Exhaust
• Warranty: 2 years from Stone Exhaust

Buyer notes

Laws differ by region. Outside the UK, please check local regulations before purchase and installation. The buyer is responsible for compliance where they drive.

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