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As a result of various regulations, many new cars feature some kind of exhaust system valve technology. The valves are generally designed to operate at different engine speeds to attenuate sound levels. Most manufacturers employ selectable or active systems. These allow the driver to choose the noise level. The purpose is to provide a quiet car until the opportunity presents itself to hit the loud pedal. At this point, the valves open to allow the vehicle to produce a louder, sportier exhaust note.
BORLA Performance Industries has developed its own valve technology to allow its exhaust systems to retain the vehicle’s factory dual-mode or active valve functionality without restricting the flow of exhaust gases leaving the engine.
While developing its performance exhaust applications for new vehicles, BORLA engineers need to understand how the valves in the stock exhaust systems operate so they can ensure the BORLA systems function in the same way. The video posted below was filmed during a test session using the 2018 Ford Mustang GT. The BORLA engineers removed the Ford valves from the stock exhaust and placed them inside the car so they could study the activation in the Mustang’s different driving modes. As you will see from the video, the valves are open less in Quiet mode and never actually close while in Track mode, for example.
This video has been shared by BORLA engineers because they thought performance enthusiasts would find the valve operation interesting and give them more insight into how active exhaust valves work.