Stone Exhaust employs state of the art 3D flow velocity measurement software and the technique of a one-piece mandrel bent pipe design. Using mechanical welding arms to accurately weld stops ash generating in the pipe wall which can cause vapor lock and poor exhaust efficiency. Stone Exhaust’s innovative manufacturing process of the catless downpipe prevents multiple welding positions and vapor lock whilst maximizing efficiency of the exhaust turbine.
- Catless downpipe for 535i, 640i, X5 xDrive 35i, X6 xDrive 35i with N55 engine.
- Unique Flex design to prevent breakage caused by extreme heat
- Crisscross welding to strengthen turbo flange
- One Piece Design
- Machine Welding
- In House Research and Development
- 3D Scanning & Reverse Engineering
- 100% OEM Fitment
BMW N55 F10 535i Turboback Stone Exhaust
BMW N55 F13 640i with Stone Exhaust Catless DP + Valvetronic Cat-back Exhaust System Sound
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 E70, E71, F06, F10, F16, 535i, 640i, X5 xDrive 35i & X6 xDrive 35i.
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.
Compatibility - N55 Engine
BMW 5 Series
- F10 535i (2009-2013)/535i xDrive (2010-2013)
- F10 LCI 535i/535i xDrive (2012-2016)
- F11 535i/535i xDrive (2009-2013)
- F11 LCI 535i (2012-2017)/535i xDrive (2013-2017)
BMW 6 Series
- F06 640i (2011-2015)
- F06 640i xDrive (2012-2015)
- F06 LCI 640i / 640i xDrive (2014-2018)
- F12 640i (2009-2015)
- F12 640i xDrive (2012-2015)
- F12 LCI 640i / 640i xDrive (2014-2018)
- F13 640i (2010-2015)
- F13 640i xDrive (2012-2015)
- F13 LCI 640i / 640i xDrive (2014-2017)
- F15 X5 35i / X5 35i xDrive (2012-2018)
- F16 X6 35i (2013-2018)/ X6 35i xDrive (2014-2018)
The Below models fit SKU: A207E only
- E70 LCI X5 35i xDrive (2009+)
- E71 X6 35i xDrive (2007+)