Stone Exhaust Eddy Catalytic Downpipe
BMW N20 F20 F21 F22 F23 F30 F31 F32 F33 F36 (120i, 220i, 320i, 328i, 420i, 428i)
Upgrade your BMW N20 with the Stone Exhaust Eddy Catalytic Downpipe for faster spool, sharper throttle response and real-world gains in horsepower and torque while staying emissions friendly. This high-flow catted downpipe for BMW 120i, 220i, 320i, 328i, 420i and 428i delivers performance you can feel across the rev range and is designed for OEM-like fitment on F20, F21, F22, F23, F30, F31, F32, F33 and F36 models.
Built from SUS304 premium grade stainless steel with a 76.2 mm (3 inch) tube diameter, Stone’s patented Eddy Catalytic technology creates a controlled vortex to purify exhaust gases and maintain optimal back pressure. At lower rpm it behaves like a 400 cell catalytic for clean emissions; at higher rpm it flows like a 100 cell catalytic for maximum power, helping prevent check engine lights and keeping the drive error free. UK MOT friendly and Euro 6 compliant.
We’ve supplied and fitted these on customer N20 cars across 1 Series, 2 Series, 3 Series and 4 Series platforms, and feedback has been consistently positive: quicker turbo response, stronger mid-range pull and a smoother top end with no warning lights.
Key benefits and features
- BMW N20 catted downpipe upgrade for F20 F21 F22 F23 F30 F31 F32 F33 F36 platforms
- Works with 120i, 220i, 320i, 328i, 420i, 428i including xDrive and LCI variants
- Patented Eddy Catalytic technology for high flow and clean emissions
- No more delay in power delivery; improved spool and throttle response
- Patented O2 sensor design accurately reads every rotating displacement for stable performance
- Noble metal catalyst helps efficiently filter exhaust gas
- Computer-simulated, optimised pipe diameter and routing
- Special 3D design for 100% OEM fitment; bolt-on, no modification required
- SUS304 premium grade stainless steel construction
- Dual cross-welding at the turbo flange for durability under extreme heat
- UK MOT friendly and Euro 6 compliant
- 76.2 mm diameter tubing for maximum flow
Why Stone Exhaust for your BMW N20 downpipe
R&D and 3D Scanning: Stone engineers reverse-engineer OEM parts by 3D scanning to identify weaknesses, then refine diameter, routing and bend angles specifically for the BMW N20 downpipe. 3D simulation optimises exhaust gas flow, thermal characteristics and pressure zones for measurable gains.
7 Axis CNC Bending: State-of-the-art 7 axis CNC bending achieves up to 98% roundness with minimal outer bore wear at 180° bends, preventing airflow obstruction and reducing weld fracture risk. Integrally moulded piping offers accuracy to less than 0.025 mm.
Advanced Welding: Crisscross and overlapping welding increases penetration and width at high-heat joints between turbo and downpipe, boosting endurance. Direct spot welding by mechanical arms ensures precision and strength for a finish that looks as good as it performs.
Compatibility
Engine: BMW N20
BMW 1 Series
- F20/F21 120i (2010-2015)
- F20 LCI 120i (2014-2018)
- F21 LCI 120i (2014-2018)
BMW 2 Series
- F22 220i (2012-2017) / 228i (2012-2016) / 228i xDrive (2013-2016)
- F23 220i (2014-2017) / 228i / 228i xDrive (2014-2016)
BMW 3 Series
- F30 320i / 328i / 328i xDrive (2011-2015)
- F30 LCI 320i / 328i (2014-2018)
- F31 320i / 328i (2011-2015)
- F31 320i xDrive / 328i xDrive (2012-2015)
- F31 LCI 328i xDrive (2014-2016)
BMW 4 Series
- F32 420i / 420i xDrive (2013-2017) / 428i / 428i xDrive (2012-2016)
- F33 420i / 428i (2013-2017) / 428i xDrive (2013-2016)
- F36 420i / 420i xDrive (2013-2017) / 428i / 428i xDrive (2013-2016)
Fitment and installation
- Direct bolt-on to the OEM turbo and exhaust with OEM-style hangers
- No cutting or modification required
- Professional fitting recommended
Prefer expert installation for your BMW N20 downpipe upgrade? Book fitting with Nforcd in Warwickshire. Request a quote: Sales@nforcd.com.
Compatibility check
Before dispatch we verify fitment against your vehicle. Provide your UK registration or the last 7 of your VIN at checkout and we will confirm compatibility for your BMW N20 F-series platform.
Part number
A205E
Manufacturer
Stone Exhaust
Warranty
Stone Exhaust 2 Year Warranty
Video
BMW F36 N20 420i Full Exhaust System
Search-friendly tags
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