How a boost controller works

Understanding how a boost controller works

Before embarking on upgrading your turbo car it is a good idea to understand how a boost controller works. This modification is simple to install and can yield significant performance increases. First and foremost if you don’t know what you are doing please research and consult the help of a professional.

In all turbo applications there is the turbo and a wastegate. The wastegate has the purpose of regulating the pressure that the turbo capable of building. The wastegate is like a check valve that opens once the diaphragm has a manifold pressure greater than the spring pressure. The opening point is defined by the spring rate in the wastegate. Most wastegate manufactures offer several different rates to match your needs.

Boost Controller Install


There are two main types of manual boost controllers: bleed, or ball & spring. A boost controller works by altering the pneumatic signal going from the turbo charger to the wastegate. The boost controllers all have that same stipulation that the set pressure can not be any lower than the wastegate spring pressure. For example you have a 10psi wastegate spring and the boost controller is set for 7 PSI. The car will still make the 10 pounds of boost before the wastegate opens.


How a boost controller works : Bleed type

The bleeder valve is a needle valve that has a very fine adjustment allowing more or less air to escape. The bleeder valve allows pressure to transmit to the wastegate at a slower rate due to the bleed. This slower controlled bleed means more pressure is required from the turbo to open the wastegate. In the image below that the farther the needle is from the seat the more air will pass through.

Bleed Boost Controller

How a boost controller works : Ball and Spring

These work like a one way check valve where a ball is secured to a seat via a spring. The force on the ball from the spring may be adjusted by compressing or releasing the spring. The pressure from the turbo must exceed the spring pressure before the valve will open.

Ball and Spring boost controller


Click here to learn more about manual boost controllers. Fierce Controllers manufactures some of the best controllers and valves in the industry. Please contact us for any questions regarding our controller.

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