Before installing any manual boost controller, it is important to have already added a high flowing exhaust and an aftermarket air intake/ air filter. This will ensure the car can breathe and will allow the turbo to spool easier.
It is imperative to have installed an aftermarket boost gauge. Most stock boost gauges are not accurate, even at stock boost levels, and lose further accuracy once stock boost is increased. Without an aftermarket boost gauge you risk damage to the engine from overboosting.
How Boost Controller Works
The wastegate actuator determines your stock boost levels. The boost controller interrupts the pressure line that runs into the wastegate actuator, allowing you to increase boost over stock levels.
Find your wastegate actuator which is usually attached to the turbo, unless you are using an external wastegate. The wastegate actuator will have a vacuum line port that runs to a boost source. The boost source is usually either the turbo’s compressor housing, the intercooler pipes, or the intake manifold. This vacuum line is where the manual boost controller will be installed. If there is a T fitting in the vacuum line between the boost source and the wastegate actuator, it will have a separate vacuum line that runs to the boost control solenoid. If you have the T fitting, remove the line that runs to the solenoid, but leave the solenoid plugged in.
The barb on the boost controller that connects to the wastegate actuator will have a small hole drilled into it. It is important to leave this hole open and never switch the wastegate barb and the boost barb.
Boost controllers typically come with approximately 3 feet of vacuum line that you can cut into 2 pieces of desired lengths. The first piece will connect from the boost barb on the controller to your boost source. The second piece will connect from the wastegate barb on the controller to the wastegate vacuum port. Tip: if you have difficulty sliding the vacuum lines onto the barbs, use a little bit of oil to lube the barbs. Block off any open boost sources with vacuum caps and use cable ties to secure all vacuum line connections. We recommend using Premium Fuel with all turbo cars, especially once you have increased your stock boost.
Now that the boost controller is installed, it’s time to test the car. We recommend leaving the adjustment knob exactly where it was when you received and installed your MBC when you begin testing. Turning the adjustment knob clockwise increases boost, turning the adjustment knob counterclockwise decreases boost. This step is critical to keep an eye on your boost gauge to make sure you do not mind over boost and cause any damage to your motor.
Drive your car in an isolated area where you will be able to stop and go several times without interfering with traffic. Slowly press the gas and watch your boost gauge climb. If the boost gauge does not hit your target, increase the boost. If the boost begins to exceed your target, decrease the boost. Repeat the steps as necessary. It typically takes between 5 to 10 adjustments to get the boost exactly on your target. We recommend starting by adjusting the boost knob in 1/2 turn increments, and as you get close to your target, you may need to make smaller adjustments. Never adjust more than 1/2 a turn at a time.
Each car has a maximum safe boost level, depending on upgrades to the vehicle and the characteristics of the fuel system, specifically how much fuel your pump and injectors can provide. It is important to research and know what the maximum boost level your specific car can safely run.
This guide serves as a basic starting point for manual boost controller installation. If you have an external wastegate or twin-turbo vehicle, the installation technique may vary slightly.