Any time your vehicle is accelerating the throttle will be open. When the throttle is open there will be an open pathway for air to travel to your engine. In this pathway there will be turbo which utilizes compressed air that is forced into the vehicle's engine once it reaches a specific pressure. After you shift gears the throttle will close. During this time the turbo does not stop spinning. As the turbo keeps spinning it will not be as difficult for it to keep functioning once you open the throttle again. This is a good thing but there is still a problem as there is nowhere for the compressed air to travel.
When the turbo is spinning and the throttle is closed there will be air that is still being compressed with no place to go. The only place that it can travel to now is where it originally came from. As this could cause the turbo to spin in the opposite direction so it must be avoided. The diverter valve is what is used to avoid this from occurring.
How the Diverter Valve Works
The compressed air will try to go back through the turbo if it cannot travel to the engine. So, when the throttle is closed there will be a risk of the turbo spinning backwards if the compressed air is not diverted to a different location. The diverter valve is responsible for diverting compressed air to a different location so it does not go through the spinning turbo again.
The diverter valve will make the air relocate to the intake stream which is where it was before it went through the turbo. The air will go through the turbo again and this will basically lead to the air continuously recycling itself until the throttle is opened again.
Problems with Stock Diverter Valves
The stock diverter valve does not work as effectively as you may like it to. When your vehicle is idling the stock valve will be open as a result of a vacuum. After you let off on the throttle the stock diverter valve will start to close. After it is closed the turbo will go to the vehicle's engine. If the throttle is let off then the turbo is let out of the stock diverter valve and is relocated to the air cleaning component.
The main issue with most stock diverter valves is that they do not operate to full capacity. Many of them have lag issues, lose turbo pressure, and respond poorly with the throttle. If you want to eliminate these problems then you may want to consider replacing your vehicle's stock diverter valve with an aftermarket diverter valve.
Comparing the Diverter Valve to the Blowoff Valve
Many people believe that the diverter valve and the blowoff valve are exactly the same. There are some similarities between the two types of valves but they are not even close to being the same. The blowoff valve is responsible for dispensing turbo boosted air to the environment instead of recycling it to the air cleaning component. When the air is let out through the blowoff valve it will most likely produce an audible noise.
As you can see, the diverter valve performs a much different task which was already covered early in this article. Also, it is important to know that the diverter valve is the better of the two types of valves. Both valves are performing the same task but they do so in a different way. Both valves are responsible for removing any compressed air from the intake stream. The diverter valve will recycle turbo boost and let it go through the turbo again so that it can continue spinning. The diverter valve does not waste the compressed air like the blowoff valve which sends the air out into the atmosphere). The diverter valve can even minimize lag problems due to the way that it operates.
Most vehicles could benefit from a diverter valve swap. The stock diverter valves are not the best as there are many problems that could be experienced with them. By replacing them with an aftermarket diverter valve your vehicle could benefit quite a lot. A diverter valve only costs around $100 to $150 to purchase and installing it is not extremely difficult. Lastly, do not think of the diverter valve and blowoff valve as the same valves because the diverter valve is actually a much better valve for any vehicle.