- Patented O2 sensor technology design provides real-time data performance by accurately sensing every rotating displacement.
- No more delayed in power delivery
- Using one of the rare noble metal to help efficiently filter out exhaust gas.
- Computer simulation to obtain the best diameter.
- Special 3D design to achieve 100% OEM fitment, no modification required.
- SUS304 Premium Grade Stainless steel.
- Dual Cross-Welding Technology providing substantial increase durability at the turbo Flange.
BMW N55 F20 M135 Stone Exhaust Sound & Dyno Run
R&D and 3D Scanning
Stone Exhaust engineers use reverse engineering by 3D scanning OEM parts to understand their functionality and identify weaknesses. Data has been collected continuously in order to analyze factors such as pipe diameter, route and degrees of the bending angles of the N55 Exhaust System found on the BMW F20, F25, F26, F30 F32, M135i, M235i, 335i, 435i, X3 35i xDrive, X4 35i xDrive & M40i xDrive.
During R&D, Stone Exhaust utilizes the 3D simulation software to stimulate the exhaust gas flow movement, thermal and pressure rise zone. Progressive improvements were continually made until the optimal performance was achieved.
7 Axis CNC Bending Machine
Stone Exhaust System are constructed utilizing a 7 axis CNC Bending Machine which is the ultimate machine for high levels of precision delivery, necessary for industries such as the aerospace and defense industries.
With the state-of-the-art bending machine, Stone Exhaust has achieved the industry’s standard to an impressive 98% roundness, whilst maintaining the wear of the outer bore at only 25% at 180°. Airflow obstruction and welding fracture problems are prevented by utilizing this technology. With the combination of the CNC Bending machine, Reverse Engineering and 3D Design Scanning, Stone exhaust has created an integrally molded exhaust pipe with an accuracy error under 0.025mm.
Crisscross and Overlapping Welding Technique
The flange between the turbo and the downpipes reaches extreme temperatures (800℃ to 1100℃) which creates stress on the connection point. By utilizing both welding techniques to increases the width and penetration of welds. This increases the endurance and tolerance of these connection points, leading to quality products with reliable performance.
Direct Spot Welding
Our highly skilled engineers perform direct spot welding to increase product strength. This is undertaken by mechanical welding arms, proven to achieve greater precision and penetration in their welds compared to manual welding, resulting in an end product that is a work of art.
Art of Welding
Compatibility - N55 Engine
BMW 1 Series
- F20 M135i /M135i xDrive (2011-2015)
- F20 LCI M135i /M135i xDrive (2015-2018)
- F21 M135i (2011+) /M135i xDrive (2012-2015)
- F21 LCI M135i /M135i xDrive (2014-2016)
BMW 2 Series
- F22 M235i (2012-2016)
- F22 M235i xDrive (2013-2016)
- F23 M235i/M235i xDrive (2014-2016)
BMW 3 Series
- F30/F31 330e/335i/ 335i xDrive (2011-2015)
BMW 4 Series
- F32 F33 F36 435i/435i xDrive (2012-2016)
- F25 X3 35i xDrive (2009-2017)
- F26 X4 35i xDrive (2013-2018)/M40i xDrive (2014-2018)