This is a quick overview of the correct way to install a manual boost controller on your turbo DSM.

First, the stock boost control system: There is a pressure source on the turbo outlet elbow (1g) or the compressor housing (2g). That pressure source goes towards the wastegate actuator, but first it has a tee in it. That T splits the source between the WGA and the BCS (boost control solenoid).

The WGA works by opening the wastegate up when it recieves a pressure signal. In order for the car (stock) to increase the boost, it uses the BCS to bleed some of the pressure in the source line off. thus decreasing the pressure that the WGA sees.

When you install a manual boost controller, you are simply replacing this system with a preloaded, pressure-activated valve. That way, the WGA won't see any pressure, until the boost goes about the preload set into the MBC.

First, remove the stock system. Unplug the BCS (or leave it plugged in and toss it aside), remove all the hoses, and cap off both the original source and the fitting before the turbo that the BCS went back to. You won't be needing any of these.

Now, install the new MBC. First, you need to pick a source. Your source has to be a decently sized pressure port AFTER the throttle body. That means that you can not use the throttle body ports (too small) and you can't use anything on the intercooler pipes. Most people tee into the BOV line, and some run a seperate source from the PCV nipple, or their own extra nipple.

You HAVE to use the intake manifold is you want proper boost control. Why is that? The manual boost controller regulates the amount the wastegate is open based on the pressure at its source. Since you want to control manifold pressure, you want the MBC and the WGA to be recieving pressure directly from there.

Using a source off the turbo or intercooler pipe can cause you to have boost that changes with weather, load, and engine speed, and can also slow down boost response. By comparison, a manifold source will be fairly steady, solid, and reliable.

Then connect the source line to the "in" side of the MBC. On most boost controllers, this is the bottom; it will always be the side opposite the adjustment screw (for ball-and-spring MBC's, which are the only kind worth running).

Then, connect the "out" port on the MBC to the wastegate actuator.

Try to minimize the length of all the hoses, and make sure to zip tie them securely such that there are no leaks. Use hose that fits over the fittings well, don't go too big or too small.

All MBC's will have some kind of vent hole after the spring; most new ones have this drilled into the body of the MBC, but some older ones have a seperate piece which goes in the out line. Make sure this is intact and uncovered.

Mount the MBC securely, and go for a test drive! Start with the boost tuned all the way down (generally counter-clockwise) and slowly bring it up to where you want.


Kyle Tarry 2004