{"product_id":"stone-exhaust-bmw-b48-f30-f32-cat-back-valvetronic-exhaust-inc-320i-420i","title":"Stone Exhaust BMW 320i\/420i (B48) Valved Cat-Back Exhaust System – F30 F31 F32 F33 F36 (incl. xDrive) | OEM Integrated Valve | Single\/Dual\/Quad Exit Options","description":"\u003cdiv\u003e\n  \u003ch2\u003eStone Exhaust switchable catback for BMW 320i and 420i B48 - F30 F31 F32 F33 F36 including xDrive\u003c\/h2\u003e\n\n  \u003cp\u003eTransform the character of your two-litre turbo BMW with the Stone Exhaust valve-controlled catback. This premium rear system unleashes a richer tone, sharper throttle response and improved flow, while keeping everyday refinement intact when the flap is shut. Designed using full 3D scanning of the factory hardware and validated on Stone’s in-house dyno, it delivers precise, direct-fit installation and a deep, refined soundtrack without cabin drone.\u003c\/p\u003e\n\n  \u003cp\u003eWe have installed and used this system ourselves at MJ Modifications and customer feedback on sound quality, craftsmanship and perfect fit has been superb. If you want a subtle commute yet an exciting soundtrack on demand, this is the upgrade to choose for your B48-powered 3 Series or 4 Series.\u003c\/p\u003e\n\n  \u003ch3\u003eWhat you will love\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003eFactory valve integration for OEM-style control through your car’s ECU\u003c\/li\u003e\n    \u003cli\u003eOptional Stone Valvetronic add-on for remote open or close via an OBDII plug-and-play controller\u003c\/li\u003e\n    \u003cli\u003eOne-piece layout for optimal gas flow and straightforward fitment\u003c\/li\u003e\n    \u003cli\u003eNo unwanted resonance in the cabin - refined on cruise, purposeful under load\u003c\/li\u003e\n    \u003cli\u003eEngineered from 3D scans for true direct-fit installation on B48 models\u003c\/li\u003e\n    \u003cli\u003eDyno-developed by Stone Exhaust for genuine performance benefits\u003c\/li\u003e\n    \u003cli\u003eBuilt with precision crisscross and overlapping welds for strength and longevity\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eValve control options\u003c\/h3\u003e\n  \u003cp\u003e\u003cstrong\u003eOEM integrated valve control\u003c\/strong\u003e - works like standard. The ECU operates the flap automatically, giving a calm drive at light throttle and a sportier tone when you ask for it.\u003c\/p\u003e\n  \u003cp\u003e\u003cstrong\u003eOptional Valvetronic controller\u003c\/strong\u003e - add a single valve remote control with a simple OBDII plug-in module so you can choose quiet or loud at the press of a button.\u003c\/p\u003e\n\n  \u003ch3\u003eVehicle compatibility - B48 models\u003c\/h3\u003e\n  \u003cp\u003e3 Series\u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003eF30 320i and 320i xDrive 2011+\u003c\/li\u003e\n    \u003cli\u003eF30 LCI 320i and 320i xDrive 2014+\u003c\/li\u003e\n    \u003cli\u003eF31 320i 2011+ and 320i xDrive 2012+\u003c\/li\u003e\n    \u003cli\u003eF31 LCI 320i and 320i xDrive 2014+\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \u003cp\u003e4 Series\u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003eF32 420i and 420i xDrive 2013+\u003c\/li\u003e\n    \u003cli\u003eF32 LCI 420i and 420i xDrive 2016+\u003c\/li\u003e\n    \u003cli\u003eF33 420i 2013+ and F33 LCI 2016+\u003c\/li\u003e\n    \u003cli\u003eF36 420i and 420i xDrive 2013+\u003c\/li\u003e\n    \u003cli\u003eF36 LCI 420i and 420i xDrive 2016+\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eTailpipe layouts and part numbers\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAP502B48\u003c\/strong\u003e - Single exit with left twin tips - uses the original bumper\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAP502NB48\u003c\/strong\u003e - Dual exit with twin tips - requires 340i or 440i rear bumper\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAP502NQB48-8200CG\u003c\/strong\u003e - Dual exit with quad tips - requires M Sport rear bumper\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eHear it\u003c\/h3\u003e\n  \u003cdiv\u003e\n    \u003ciframe allow=\"accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen=\"\" frameborder=\"0\" height=\"480\" width=\"854\" src=\"https:\/\/www.youtube.com\/embed\/BFX0HSexkpI\" title=\"Stone Exhaust sound clip\"\u003e\u003c\/iframe\u003e\n  \u003c\/div\u003e\n  \u003cdiv\u003e\n    \u003ciframe allow=\"accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen=\"\" frameborder=\"0\" height=\"480\" width=\"854\" src=\"https:\/\/www.youtube.com\/embed\/J_4rDcujVCM\" title=\"Stone Exhaust system sound\"\u003e\u003c\/iframe\u003e\n  \u003c\/div\u003e\n\n  \u003ch3\u003eDyno developed\u003c\/h3\u003e\n  \u003cdiv\u003e\n    \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0284\/6300\/5795\/files\/Stone_Exhaust_BMW_N20_B48_F30_F32_Cat-Back_Valvetronic_Exhaust_Inc._320i_420i_600x600.png?v=1590757256\" alt=\"Stone Exhaust dyno development for BMW B48 catback\"\u003e\n  \u003c\/div\u003e\n\n  \u003ch3\u003eInstalled examples\u003c\/h3\u003e\n  \u003cdiv\u003e\n    \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0284\/6300\/5795\/files\/Untitled_2e3e0d3f-f88a-4c69-89f1-a48e9b8477e7_600x600.png?v=1588766527\" alt=\"Stone Exhaust fitted - dual exit layout\"\u003e\n  \u003c\/div\u003e\n  \u003cdiv\u003e\n    \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0284\/6300\/5795\/files\/Untitled1_7e8db30e-c8d4-427a-aaeb-9d917125875a_600x600.png?v=1588766534\" alt=\"Stone Exhaust installed - B48 platform\"\u003e\n  \u003c\/div\u003e\n\n  \u003ch3\u003eEngineering detail that sets it apart\u003c\/h3\u003e\n  \u003cp\u003e\u003cstrong\u003eR and D with 3D scanning\u003c\/strong\u003e\u003cbr\u003eStone maps the factory system to optimise tube diameters, routing and bend geometry for the B48 platform. Computational analysis of gas speed, pressure and temperature helps achieve the best blend of tone and flow while ensuring exact fitment.\u003c\/p\u003e\n  \u003cdiv\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 reverse engineering by Stone Exhaust\"\u003e\n  \u003c\/div\u003e\n\n  \u003cp\u003e\u003cstrong\u003e7 axis CNC bending\u003c\/strong\u003e\u003cbr\u003ePrecision mandrel bends maintain roundness and minimise deformation at tight angles, cutting restriction and keeping welds stress free. With reverse engineering and CNC-controlled forming, tolerances are exceptionally tight for a true direct fit.\u003c\/p\u003e\n  \u003cdiv\u003e\n    \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0284\/6300\/5795\/files\/bending.jpg?v=1572739395\" alt=\"Stone Exhaust 7 axis CNC bending quality\"\u003e\n  \u003c\/div\u003e\n\n  \u003cp\u003e\u003cstrong\u003eAdvanced welding techniques\u003c\/strong\u003e\u003cbr\u003eCrisscross and overlapping welds reinforce high heat areas for long-term durability, while mechanical spot welding ensures consistency and a premium finish.\u003c\/p\u003e\n  \u003cdiv\u003e\n    \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0284\/6300\/5795\/files\/Stone_Exhaust_Art_of_Welding_-_1_1024x1024.jpg?v=1572828150\" alt=\"Stone Exhaust welding quality - detail 1\"\u003e\n  \u003c\/div\u003e\n  \u003cdiv\u003e\n    \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0284\/6300\/5795\/files\/Stone_Exhaust_Art_of_Welding_-_2_1024x1024.jpg?v=1572828178\" alt=\"Stone Exhaust welding quality - detail 2\"\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\u003eProfessional fitting\u003c\/h3\u003e\n  \u003cp\u003eFor supply and installation, choose MJ Modifications in Warwickshire. We offer expert fitting and bumper conversion advice for twin or quad layouts. Request a quote at \u003ca href=\"mailto:info@mjmodifications.co.uk\"\u003einfo@mjmodifications.co.uk\u003c\/a\u003e.\u003c\/p\u003e\n\n  \u003ch3\u003eHelpful search terms\u003c\/h3\u003e\n  \u003cp\u003eBMW 320i sports exhaust, BMW 420i sports exhaust, F30 F31 F32 F33 F36 switchable exhaust, B48 turbo catback, BMW flap exhaust, BMW ECU valve exhaust, BMW 3 Series performance rear system, BMW 4 Series performance rear section, BMW xDrive compatible exhaust, BMW twin tip upgrade, quad tip upgrade, dual exit rear conversion, direct fit exhaust for BMW B48, plug-in OBD valve controller, back box upgrade, BMW 320i sound upgrade, BMW 420i sound upgrade, Stone Exhaust UK dealer, no drone BMW exhaust, performance exhaust for 2.0 turbo BMW.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Stone Exhaust","offers":[{"title":"Single Exit with (Left) Twin Tailpipes \/ Require Original Bumper \/ Flat Cut Gloss Carbon Fibre (82mm)","offer_id":56008717500802,"sku":null,"price":2396.16,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0871\/5445\/8937\/files\/STONEEXHAUSTBMWB48F30F32CAT-BACKVALVETRONICEXHAUST_INC.320I_420I__11_1946x_2829d8e9-cfee-44eb-a93a-184dbebcda37.jpg?v=1764091278","url":"https:\/\/mjmodifications.co.uk\/products\/stone-exhaust-bmw-b48-f30-f32-cat-back-valvetronic-exhaust-inc-320i-420i","provider":"MJ Modifications","version":"1.0","type":"link"}