Stone Exhaust BMW B48D G20 G21 Catless Downpipe for OPF Models (320i 330i 420i 430i) – Part Number A218E
Upgrade your BMW B48 2.0 turbo with the Stone Exhaust catless downpipe for OPF cars – the go-to BMW G20 G21 G22 G23 G26 B48 downpipe for serious performance, faster spool and a more aggressive exhaust note. Designed for the BMW 3 Series 320i 330i xDrive and 4 Series 420i 430i, plus the G29 Z4 20i 30i, this decat downpipe is a direct-fit, bolt-on solution that reduces back pressure and unlocks power potential, especially when paired with a performance remap. If you are searching for BMW B48 catless downpipe, BMW 330i downpipe, BMW 320i decat, BMW 420i downpipe, BMW 430i decat, BMW G20 G21 downpipe OPF or BMW B48 OPF downpipe, this is the high-quality stainless steel option you want.
Why choose the Stone Exhaust B48 Catless Downpipe
- Optimised for BMW B48D OPF cars – BMW G20 G21 320i 330i xDrive, BMW G22 G23 G26 420i 430i, BMW G29 Z4 20i 30i.
- Catless, free-flow design for reduced back pressure, quicker turbo spool and sharper throttle response.
- SUS304 stainless steel construction for strength, durability and corrosion resistance.
- Precision formed on a 7‑axis CNC bending machine for excellent roundness and smooth flow.
- Dual cross-welding and direct spot welding to handle extreme turbo flange temperatures and ensure long-term reliability.
- Accurate O2 sensor placement designed to provide stable data feedback and address typical delay or error issues.
- Direct-fit, no cutting or extra modification – designed to match OEM routing and connections.
Real-world results from Nforcd
We have installed this Stone Exhaust BMW B48 catless downpipe on customer cars and our own fleet. Feedback has been consistently positive – faster spool, a stronger mid-range and the deeper, sportier sound enthusiasts expect from a quality decat downpipe. If you want the best BMW 330i downpipe upgrade for OPF models, this is the one we recommend.
Stone Exhaust engineering
Stone Exhaust uses 3D scanning and reverse engineering of OEM BMW parts to map pipe diameter, route and bend geometry for the B48D platform. Flow, thermal and pressure zones are simulated and refined to maximise performance. The result is a high-precision, integrally moulded downpipe with excellent fitment and minimal flow disturbance.
- 7‑axis CNC bending achieves up to 98 percent roundness and reduces outer bore wear at tight bends.
- Crisscross and overlapping welds at critical joints increase penetration and strength.
- Mechanical direct spot welding provides consistent, high-precision welds.
Compatibility – BMW B48D OPF models
BMW Z Series
- G29 Z4 20i / 30i (2019+)
BMW 3 Series
- G20 / G21 320i (2019+)
- G20 / G21 330i / 330i xDrive (2017+)
BMW 4 Series
- G22 420i / 430i (x) (2020+)
- G23 420i / 430i (X) (2020+)
- G26 420i / 430i (x) (2020+)
Part number
A218E
Fitting and support
Professional installation recommended. For fitting, choose Nforcd in Warwickshire – request a quote at Sales@nforcd.com. We are BMW B48 downpipe specialists and can advise on OPF compatibility, tuning and aftercare.
Manufactured by
Stone Exhausts
Warranty
Stone Exhaust 2 year warranty.
Emissions notice
Various regions have laws regulating aftermarket exhaust parts, especially when catalysts are removed or modified. Please check and comply with the laws in your area before installation. Intended for off-road or motorsport use where permitted. The purchaser is responsible for ensuring legal compliance.
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