We are proud to introduce you to the state of the art Stone OEM Integrated Valved OPF-Back Exhaust with dual valves, to enhance the performance and sound of your BMW F80 Sedan M3 & F82 Coupe M4 with the S55 engine.
Stone Exhaust has been developing world's best exhaust system since 1998, starting with 3D scanning and reverse engineering the OEM system, this allows the Stone engineers to design a 100% OEM fitment exhaust with precision. With their in-house dyno, your BMW exhaust system is proven to produce more power with the enhanced Stone signature exhaust sound.
The OEM Integred Valves option allows your exhuast system to operate as standard, where the onboard computer (ECU) will control the opening and closing of the valves automatically.
You may wish to add the Stone Valvetronic System (Dual Valves) which enables you to control the valves remotely via the stone remote controller.
- OEM Integrated OPF-Back Exhaust System
- Optional Stone Valvetronic System available
- Plug and Play OBDII controller
- One Piece Design
- Machine Welding
- In House Research and Development
- 3D Scanning & Reverse Engineering
- Dyno Developed In House
Eliminates drone found on the standard exhaust system
Stone Exhaust M3 & M4 Catless Downpipe with Stone Valvetronic Exhaust System Sound
Stock Figure: 444 hp
Stone Exhaust BMW S55 F82 M4 OPF-Back Exhaust System: 473.7 hp
+9.8nm of torque
Fitted Photo(s) - Dual Exit with Quad Tailpipes
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 S55 Exhaust System found on the F80 M3 & F82/F83 M4.
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.
The Stone Valvetronic System was independently researched and developed in house. The system forgoes the conventional design of complicated wiring and the rubber inside the valve which is prone to aging, to ensure longevity.
With the Valvetronic remote control providing three modes to choose from: ON / OFF / AUTO, this allows for instant switching between modes in accordance to driving conditions faced. So, let the STONE Valvetronic System adapt to your vehicle’s needs.
The Valvetronic remote control has 3 modes, ON / OFF / AUTO, which allows you to open and close the valve at a click of a button. The Auto mode allows customization of the opening and closing of the valve at a predefined RPM.
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 - S55 Engine
BMW M Series
- F80 M3 (2012-2015)
- F80 LCI M3 (2015-2018)
- F82 M4 (2013-2017)
- F82 LCI M4 (2016-2018)