{"product_id":"stone-exhaust-bmw-b58d-g20-g21-eddy-catalytic-downpipe-gpf-m340i-m340i-xdrive","title":"Stone Exhaust Eddy Catted Downpipe with GPF\/OPF for BMW B58D \u0026 Toyota GR Supra A90 – G20 M340i\/M340i xDrive, G21 340i xDrive, G29 Z4 M40i – Euro 6 Compliant, No CEL (A223E)","description":"\u003cdiv class=\"product__description rte\"\u003e\n  \n  \u003ch2\u003eHigh Flow Sports Catalyst Front Section for B58D and A90 Supra\u003c\/h2\u003e\n  \u003cp\u003eUnleash faster spool, stronger mid-range and a richer, motorsport tone with Stone Exhaust’s Eddy catalytic front pipe. Built for vehicles with gasoline particulate filters, this GPF and OPF compatible primary cat section offers serious performance without the hassle. It is Euro 6 compliant, MOT friendly and designed to run without engine management lights or fault codes on supported applications.\u003c\/p\u003e\n  \n  \u003cp\u003e\u003cstrong\u003ePart Number\u003c\/strong\u003e: A223E\u003c\/p\u003e\n  \n  \u003ch3\u003eWhat makes the Eddy catalyst special\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003ePatented Eddy flow core spins exhaust gas to enhance conversion efficiency while maintaining ideal turbine back pressure for power.\u003c\/li\u003e\n    \u003cli\u003eVariable behaviour core acts like a low-cell performance cat when you are on throttle, then like a finer-cell catalyst during cruise for clean emissions and smooth drivability.\u003c\/li\u003e\n    \u003cli\u003eNo EML and no error messages thanks to optimised lambda sensor positioning that preserves accurate feedback to the ECU.\u003c\/li\u003e\n    \u003cli\u003eDirect-fit to factory turbo outlet and OE brackets. No cutting. No coding. No additional hardware required on listed models.\u003c\/li\u003e\n    \u003cli\u003eConstructed from premium SUS304 stainless steel for long term durability and corrosion resistance.\u003c\/li\u003e\n    \u003cli\u003ePrecisely formed with 7-axis CNC mandrel bends for exceptional roundness and uninterrupted gas flow.\u003c\/li\u003e\n    \u003cli\u003e3D scanned and CAD modelled to follow OEM routing and clearances for a perfect fit on B58D platforms.\u003c\/li\u003e\n    \u003cli\u003eCriss-cross overlap TIG welds at heat-critical joints for strength you can rely on under sustained boost.\u003c\/li\u003e\n    \u003cli\u003eEuro 6 compliant design for road use where applicable.\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \n  \u003ch3\u003eReal gains you can feel\u003c\/h3\u003e\n  \u003cp\u003eExpect earlier boost, sharper throttle response and a deeper, more refined soundtrack without intrusive drone. We have installed this unit on our own builds and customer cars at MJ Modifications and feedback has been excellent, with owners praising the improved punch and seamless integration with factory systems.\u003c\/p\u003e\n  \n  \u003ch3\u003eVehicle applications\u003c\/h3\u003e\n  \u003cp\u003e\u003cstrong\u003eBMW B58D engine\u003c\/strong\u003e\u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003eG20 M340i 2018+\u003c\/li\u003e\n    \u003cli\u003eG20 M340i xDrive 2018+\u003c\/li\u003e\n    \u003cli\u003eG21 340i xDrive 2018+\u003c\/li\u003e\n    \u003cli\u003eG29 Z4 M40i 2019+\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \u003cp\u003e\u003cstrong\u003eToyota\u003c\/strong\u003e\u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003eGR Supra A90 2020 to present\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \n  \u003ch3\u003eInstallation and fitting\u003c\/h3\u003e\n  \u003cp\u003eThis is a true plug-and-play replacement for the OE primary catalyst, reusing original mounting points and sensors. For professional fitting, heat cycle checks and aftercare, book with MJ Modifications in Warwickshire. Request a fitting quote at \u003ca href=\"mailto:info@mjmodifications.co.uk\"\u003einfo@mjmodifications.co.uk\u003c\/a\u003e.\u003c\/p\u003e\n  \n  \u003ch3\u003eEngineering highlights\u003c\/h3\u003e\n  \u003cp\u003eEach application is reverse engineered by 3D scanning the factory part to capture precise geometry. Flow, pressure and thermal behaviour are then simulated to optimise diameter and bend radii. Manufacturing uses a 7-axis CNC bender to maintain tube roundness, followed by direct spot welding and reinforced overlap TIG seams at the turbo flange and high-heat areas for maximum reliability.\u003c\/p\u003e\n  \n  \u003cdiv style=\"margin: 16px 0;\"\u003e\n    \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0284\/6300\/5795\/files\/1_9336c8b0-c9ea-4822-891c-83490f630707.jpg?v=1572705528\" alt=\"3D scanning and CAD development of Stone Exhaust catalyst section for B58 and A90 Supra\"\u003e\n  \u003c\/div\u003e\n  \u003cdiv style=\"margin: 16px 0;\"\u003e\n    \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0284\/6300\/5795\/files\/bending.jpg?v=1572739395\" alt=\"7-axis CNC mandrel bending for smooth flow and precision fitment\"\u003e\n  \u003c\/div\u003e\n  \n  \u003ch3\u003eWarranty\u003c\/h3\u003e\n  \u003cp\u003eStone Exhaust 2 year warranty.\u003c\/p\u003e\n  \n  \u003ch3\u003eManufacturer\u003c\/h3\u003e\n  \u003cp\u003eStone Exhaust\u003c\/p\u003e\n  \n  \u003ch3\u003eVideo\u003c\/h3\u003e\n  \u003cp\u003e\u003cstrong\u003eBMW G29 B58D Z4 M40i - Stone Eddy Catted Front Pipe\u003c\/strong\u003e\u003c\/p\u003e\n  \u003cp\u003e\n    \u003ciframe width=\"1280\" height=\"720\" src=\"https:\/\/www.youtube.com\/embed\/UX29BUit9Ww\" title=\"Stone Exhaust Eddy Catalytic Front Section on BMW G29 Z4 M40i\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen\u003e\u003c\/iframe\u003e\n  \u003c\/p\u003e\n  \n  \u003ch3\u003eBuy with confidence from MJ Modifications\u003c\/h3\u003e\n  \u003cp\u003eWe supply, install and support Stone Exhaust products across BMW B58D platforms and the Toyota GR Supra A90. If you want OE-level fit, emissions-friendly performance and a CEL-free experience, this is the upgrade to choose. For availability and workshop booking, email \u003ca href=\"mailto:info@mjmodifications.co.uk\"\u003einfo@mjmodifications.co.uk\u003c\/a\u003e.\u003c\/p\u003e\n  \n  \u003cp\u003e\u003cstrong\u003ePart Number\u003c\/strong\u003e: A223E\u003c\/p\u003e\n  \n  \u003ch3\u003ePopular searches\u003c\/h3\u003e\n  \u003cp\u003eBMW M340i sports cat, M340i front pipe with cat, B58D performance catalyst, Supra A90 catted front pipe, Z4 M40i catalyst upgrade, GPF safe sports catalyst, OPF compatible cat section, Euro 6 legal sports cat, B58 turbo outlet pipe, primary cat replacement B58, stainless 304 catted pipe, CEL free catalytic upgrade, lambda sensor friendly cat, plug and play cat for M340i, G20 G21 G29 cat section, Toyota MK5 Supra sports cat, high flow catalytic converter B58, Stone Exhaust Eddy cat UK, A223E Stone cat, performance exhaust catalyst for B58, turbo spool improvement cat, MOT friendly catted front section.\u003c\/p\u003e\n  \n\u003c\/div\u003e","brand":"Stone Exhaust","offers":[{"title":"Default Title","offer_id":56005658739074,"sku":null,"price":1589.76,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0871\/5445\/8937\/files\/1705291_x800_b0c200d4-b953-4528-ab00-24494700b780.webp?v=1764021242","url":"https:\/\/mjmodifications.co.uk\/products\/stone-exhaust-bmw-b58d-g20-g21-eddy-catalytic-downpipe-gpf-m340i-m340i-xdrive","provider":"MJ Modifications","version":"1.0","type":"link"}