What Is a Bailey Dump Valve?
A dump valve is used in performance vehicles (vehicles that have a turbo functionality) to ‘blow off’ excess boost pressure when working through the gears. They have been around since the 1980’s and, as cars have advanced, have advanced to keep up with new trends. They have also become more sophisticated in order to keep up with the development of new cars, engines and boost systems.
Bailey dump valves are generally non-return valves to reduce damage that could be caused by over-boosting. The functionality of a dump valve is to prevent back pressure of boost that would bend valves and blow heads which in turn could cause severe damage to the car’s engine.
How does it work? It follows the simple principles of boost and release. This means that once the engine gets to its boost pressure it has to somehow release that pressure in order to reduce the revolutions that it runs at – meaning that it is necessary to change gears. The dump valve therefore works during the process of changing gears.
Furthermore bailey dump valves also help with the breaking system of a vehicle. This means that the turbo uses vacuum pressure to boost the engine, reducing the vehicles ability to brakes. The cause for the inability to break is the fact that the turbo sucks the vacuum out of the brake booster. Therefore the dump valve re-introduces the vacuum into the brake booster, allowing you to brake.
Dump valves are only used in vehicles that have a boost pressure of more than 1 bar. Boosting more than 1 bar means that you will need more sophisticated spare parts in your vehicle. These include high-pressure tubing, high-pressure petrol pumps, bigger fuel injectors, ceramic coated pistons etc.
The downside of a dump valve is that it has a limited lifespan. Over-boosting a dump valve will cause the valve’s diaphragm to disintegrate, causing the engine to cease or blowing the turbo resulting in huge repair costs.
This means that you need to service and clean your dump valve on a regular basis. Maintaining your dump valve requires regular lubrication and regular inspection of the diaphragm. You need to also check for leaks on the feed and return pipes, making sure that the turbo oil valve is open and not blocked. You also need to make sure that the dump valve isn’t near an excessive heat source that could damage or perish any rubber parts including the o-rings and springs.
Overheating will cause the spring to collapse and the dump valve to leak which will significantly reduce the performance of the valve and therefore the vehicle.
It is therefore wise to maintain your dump valve.