Valved exhaust systems: how do they work and should you keep the valves?

How does a valved exhaust work?

A valve is a flap located in the exhaust system, opened or closed by a small actuator. When closed, it forces the gases through a longer, quieter path. When open, it gives them a direct path, resulting in a freer, more pronounced sound.

Operating modes

Depending on the vehicle and the exhaust system, the valves can be controlled in several ways:

• Automatically, based on engine speed and load.
• Via the drive mode (comfort, sport, individual), when the car allows it.
• With a dedicated control, such as a remote or a control module, depending on the part number.

The delete or control module

A valve module lets you take back control of how the valves operate: keep them open at all times, force them to stay closed or control them on demand, depending on the product. This is useful when the factory system doesn't offer enough options, or when the car has no drive mode to control them.

Your neighbors

Used properly, valves are precisely what let you stay discreet: closed at startup, in town and in quiet neighborhoods, open when the situation allows. Your neighbors are the main reason to keep them. A system left permanently open will be louder at startup and at steady engine speed.

Should you keep them?

• Keep them if the car is a daily driver, if you want two personalities in one, or if you start up early in the morning.
• Disable or delete them if the car is dedicated to fun or motorsport and you want a consistent sound.

Note: modifying how the valves operate may void the system's homologation, depending on the part number. Always check the product description.

View valved exhaust systems and modules

Find valved exhaust systems and valve modules in Hubshop's dedicated categories. To check compatibility with your car, keep your VIN handy.

Legal notice: non-homologated exhaust systems and modules are reserved for motorsport use, on closed circuits or off public roads. On the road, the vehicle's noise level must comply with current regulations.