Bleed or Ball and Spring Manual Boost Controller. Which is the Best?

The difference between bleed or ball and spring manual boost controller.

Before we get started on the specifics on choosing a bleed or ball and spring manual boost controller, let’s review how a typical single turbo setup is installed. Combustion engines are essentially air pumps. They suck in air and fuel, ignite, and the expanding gasses exit from the exhaust. You can increase engine power by increasing the amount of air that the engine can take in. This can come from larger intakes, heads, cams, and a free flowing exhaust. Another option is to effectively increase the atmospheric pressure at which the engine operates. This is accomplished by providing boost via a turbocharger or supercharger. Check out the video to get a good understanding of how the internal combustion engine works.


Now, let’s learn about a turbocharger system. There are four major components in a turbo system. Each one must work in harmony with each other to provide safe horsepower producing boost.

Typical Turbo Diagram

  • The Turbocharger- This is the heart of the system. Hot exhaust gasses rapidly flow into the turbine housing. The hot air compresses and flows around the turbine blades causing the axis to spin. On the other side of the spinning axis is the compressor that sucks in ambient air, and then compresses it. We offer Turbochargers by Garret, Turbonetics, and HKS. If you do not see what you want we can probably get it…just ask.
  • The Wastegate-This is the brain of the system. It is directly responsible for controlling how much pressure the turbo will make. It is installed parallel to the turbo. Once the predetermined boost is reached, the wastegate opens allowing the excess gas to escape. There are two types of wastegates: internal and external. The function is essentially the same. We also offer wastegates from leading manufactures such as Turbosmart, TiAL sport, HKS, and others.
  • The Intercooler-When the compressed air leaves the turbo, it is heated to an unacceptable level. We want to cool the air to fight against detonation and to increase horsepower. The intercooler is a heat exchanger similar in function to the radiator of the car. There are two main types of intercoolers: Air/Air and Air/Water. Air/Air intercoolers are more common for street vehicles due to their simplicity and better performance in a constant moving vehicle. For race applications, the colder the water the better. So an Air/Water intercooler with ice in the tank works the best.
  • The Blow off Valve (BOV)- This is installed on a T between the intercooler and the engine’s intake. You can have a recirculating or a vent valve. Basically, if the air is measured before the BOV then you need to use a recirculating type. The purpose of this valve is to relieve the pressure when the accelerator pedal is released, for example, in between shifts. If the pressure is not released fast enough, you will get surge on the turbo’s compressor, and thus a shorter life cycle of the turbo. You should also use BOVs on supercharged applications for the same reason.

Before we can make a choice on bleed or ball and spring manual boost controller, we need to understand the function of the MBC. The purpose of the MBC is to allow a defined pressure to apply a positive force to the diaphragm of the wastegate. The pressure that is allowed to pass through the system is regulated by the boost controller.

bleed or ball and spring manual boost controller


There are two types of manual boost controllers (MBC) that are currently on the market: bleed or ball and spring manual boost controller. Each one has its own unique set of advantages that should be evaluated by the installer. 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. These valves are extremely stable and are not prone to producing boost spike (when the system overshoots the target pressure), which may happen in high boost applications. Though these are more stable, they do not offer any assistance in spool-up time. They are essentially a controlled boost leak, and as a result, they leave potential performance gains performance.Bleed Boost Controller

The second type of valve is a ball and spring manual boost controller. These typically have a spring that is held under compression by a seated ball and a set screw. The set screw can be adjusted to provide more or less force on the ball. The more force on the ball, the more pressure is required to push the ball up and allow the system to flow. These have a distinct advantage in that they do not allow any pressure to reach the wastegate diaphragm until the pressure is high enough to overcome the manual boost controller spring. The means the wastegate will not begin opening until right before the designated pressure range. Customers with this type of valve have experienced an 500-800rpm decrease in spool time. That’s huge for a street performance car! The downside of these valves is the reaction time. If it is not properly engineered, the system can overshoot its specified pressure causing a boost spike. This can be overcome by using properly designed bleed ports, high tolerance machining, and lightweight materials for the ball such as ceramic.

Ball and Spring boost controller

Many auto enthusiasts have their personal preferences when it comes to bleed or ball and spring manual boost controller. At Fierce controllers, we spend the manufacturing and engineering resources to make a product that will consistently perform to the highest expectations. 100% of our valves go through a stringent assembly and post-assembly testing process. Yes, we hand test every single valve that leaves our Tampa, FL facility to ensure that you get the high quality parts you desire. Don’t waste performance, but most importantly, don’t risk your build on inferior parts.

Click Here for more information on our boost controllers

-Chris Campbell, CEO

Fierce Controllers

CDC Innovations LLC

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