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