Stone Exhaust BMW N20 Eddy Catalytic Downpipe - E84 E89 F25 F26 - X3 20i xDrive, X4 20i xDrive, X3 28i xDrive, X4 28i xDrive
Unlock performance and keep emissions in check with the Stone Exhaust eddy catalytic downpipe for the BMW N20 engine. This high flow catted downpipe is engineered for precise OEM fitment, faster spool, stronger mid range torque and a sharper throttle response while remaining UK MOT friendly and Euro 6 compliant. A direct bolt on turbo downpipe upgrade for BMW X1, X3, X4 and Z4 N20 models, it delivers the sound, flow and durability enthusiasts want with no error codes or check engine light.
Why enthusiasts choose this BMW N20 downpipe
- Patented eddy catalytic technology - vortex flow promotes efficient exhaust gas purification while maintaining balanced back pressure for power
- Real world gains - improved horsepower and torque versus straight downpipes in comparative testing
- No CEL - O2 sensor design provides accurate real time data, no error codes and no check engine light
- High flow catted downpipe - noble metal catalyst efficiently filters exhaust gases
- Direct fit OEM replacement - special 3D design for 100 percent OEM fitment, no modification required
- SUS304 premium grade stainless steel - corrosion resistant, long lasting performance
- Stronger turbo flange - Dual cross welding technology for durability at extreme temperatures
- UK MOT friendly and Euro 6 compliant
At Nforcd we have installed this Stone Exhaust BMW N20 downpipe for customers and the feedback has been excellent on fitment, quality and drivability. If you want a high flow, catted, direct fit BMW N20 downpipe that performs and avoids dash lights, this is the one.
Eddy Catalytic Technology - engineered flow, real performance
Unlike conventional linear frustum sport cats, Stone’s patented eddy catalytic technology uses an arc packaging method. Turbocharger outflow generates a controlled vortex that enhances purification while maintaining balanced back pressure. The result is efficient emissions control with improved response and measurable gains in power and torque compared to straight downpipes in Stone’s testing.
Precision manufacturing for the BMW N20 platform
R&D and 3D Scanning
Stone engineers reverse engineered the OEM BMW N20 exhaust by 3D scanning to analyse pipe diameter, routing and bend angles across E84, E89, F25 and F26 platforms. 3D simulation was used to study exhaust gas flow, thermal zones and pressure, iterating until optimal performance was achieved.
7 Axis CNC Bending
Constructed with a 7 axis CNC bending machine for aerospace level precision. Achieves up to 98 percent roundness and limits outer bore wear to only 25 percent at 180 degrees, helping prevent airflow obstruction and weld fractures. Combined with 3D design scanning, Stone delivers an integrally moulded pipe with accuracy error under 0.025 mm.
Crisscross and Overlapping Welding + Direct Spot Welding
The turbo to downpipe flange experiences extreme temperatures, typically 800°C to 1100°C. Stone’s crisscross and overlapping welds increase width and penetration, improving endurance and tolerance at this critical joint. Direct spot welding by mechanical arms further enhances precision and strength.
Key features at a glance
- Patented O2 sensor positioning for accurate feedback
- Faster power delivery, reduced lag
- No error codes, no check engine light
- Noble metal catalyst for efficient filtration
- Computer simulated optimised diameter and routing
- 100 percent OEM fitment, no modification required
- SUS304 premium grade stainless steel construction
- Dual cross welding at turbo flange for durability
- UK MOT friendly, Euro 6 compliant
Compatibility - BMW N20 engine
BMW X Series
- E84 X1-X4 20i 28i (2008 - 2015)
- F25 X3 20i 2013-2017, X3 20i xDrive 2011-2017
- F25 X3 28i 2013-2017, X3 28i xDrive 2009-2017
- F26 X4 20i xDrive 2013-2018
- F26 X4 28i xDrive 2013-2018
BMW Z Series
- E89 Z4 20i 30i (2008 - 2016)
Part number
A206XE
Fitting and installation
Professional fitting is recommended. Nforcd offers in-house installation in Warwickshire for this BMW N20 eddy catalytic downpipe. Request a fitting quote at Sales@nforcd.com.
Manufacturer and warranty
Manufactured by: Stone Exhaust
Warranty: Stone Exhaust 2 year warranty
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