Stone Exhaust BMW B48 G20 G21 G22 G23 OEM Integrated Valved Cat-Back Exhaust for 330i and 430i
Transform the sound and performance of your BMW 330i or 430i with the Stone Exhaust OEM integrated valved cat-back exhaust system for the B48 engine. Engineered for G20, G21, G22 and G23 BMW platforms, this Stone cat-back delivers a sharper, richer exhaust note with genuine OEM fitment, no unwanted drone and proven power gains on the in-house dyno. Designed through 3D scanning and reverse engineering of the factory system, it bolts up cleanly and precisely while elevating everyday driveability and track-day excitement.
We run Stone Exhaust on customer cars and in our own builds at Nforcd. Feedback has been consistently positive for build quality, fit and finish, and the refined yet aggressive B48 soundtrack. If you are searching for a BMW G20 cat back exhaust, BMW 330i valved exhaust or BMW 430i performance exhaust, this is the upgrade that ticks every box.
Why choose this Stone Exhaust cat-back
- OEM integration for the factory valve setup on B48 models for true plug-and-play fitment
- Available with Stone Valvetronic control kit and OBDII plug-and-play controller for manual open or close and auto valve control by RPM
- Eliminates the typical drone found on many standard and aftermarket systems
- Developed on Stone Exhaust’s in-house dyno for measurable performance gains with the signature Stone sound
- One piece design for optimal flow and straightforward installation
- 3D scanning and reverse engineering ensure 100 percent OEM-style fit
- 7 axis CNC bending delivers up to 98 percent roundness and exceptional accuracy for smooth gas flow
- Crisscross and overlapping welding techniques enhance strength and durability at high thermal stress points
- Direct spot welding by mechanical arms for precise, consistent weld penetration
- OPF delete harness available free of charge for OPF or GPF equipped cars to prevent error codes without ECU coding
- xDrive compatible
What you will notice
- Deeper, cleaner B48 tone with more presence when the valves are open
- Refined volume for daily use with valves closed
- Smoother flow from precision-formed pipework and optimised routing
- Real world power improvements validated on Stone’s dyno
Recommended pairing
Often purchased with the Stone Exhaust BMW B48 G20 G30 Catless Downpipe or the Stone Exhaust BMW B48 G20 G30 Eddy Catalytic Performance Downpipe for further performance and sound enhancement.
Compatibility
B48 engine BMW 3 Series and 4 Series:
- BMW 3 Series G20 Saloon 330i and 330i xDrive
- BMW 3 Series G21 Touring 330i and 330i xDrive
- BMW 4 Series G22 Coupe 430i and 430i xDrive
- BMW 4 Series G23 Convertible 430i and 430i xDrive
- BMW 4 Series G26 Gran Coupe 430i and 430i xDrive
OPF delete information
Stone offers an OPF delete solution that can be included free of charge. This allows installation on OPF or GPF equipped cars without triggering an error code, so no ECU coding is required.
R&D and manufacturing
Stone engineers 3D scan the OEM exhaust to analyse diameter, bend angles and routing before simulating gas flow, thermal zones and pressure in software. Production uses a 7 axis CNC bending machine for exceptional roundness and accuracy, with direct spot welding and crisscross or overlapping welds to maximise strength where temperatures are highest.
Sound check videos
Installation and fitting
Direct bolt-on fitment with OEM integration. Professional installation recommended. Nforcd offers expert fitting in Warwickshire. Request a quote at Sales@nforcd.com.
Warranty
Stone Exhaust 2 year warranty.
Part number
AP537
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