When a car changes from a boosted state to a closed throttle state, air becomes pressurised. Something simple, like a driver changing gear could cause this to happen. Dump valves ensure pressure isn't forced back into the engine, and release the air back into the atmosphere safely. Every car is fitted with some form of valve to relieve pressure, but the noise dump valves make attract many drivers to make the switch. As excess pressure is released into the atmosphere, a distinct hissing can be heard. Different dump valves create different noises, so you can select one to suit your preference. To find the perfect dump valve for your car, simply enter your registration number in the tool above to begin exploring the range today. If you’d like any further information, don’t hesitate to call us, or drop into one of our 200-plus branches.