BO-OST Controller

So, when I was building my car, I was mostly rebuilding what was already there, just in another chassis. The previous owners of my engine had already tuned and equipped it. Part of that equipment was a better than stock boost controller. The controller that came on the car was a Blitz Dual SBC boost controller. Seen here:

For those who don't know how a turbo works, there is this thing called a wastegate. The wastegate functions as a turbo speed controller. As the pressure increases on the manifold side of the turbo, it will open up allowing the exhaust gas to bypass the hot side of the turbo, slowing down the turbo preventing over-boost, and damage to the turbo. Most stock, and manual boost controllers function linearly, meaning that as soon as there is positive pressure in the turbo system, it starts letting exhaust bypass the turbo, and once you are at full boost, the wastegate will be fully open.

Here is a basic diagram of a non-controlled turbo set up:

 

As hinted above, the big problem with this set up is that as soon as you have ANY boost, the waste gate opens allowing exhaust go by that could be used to help build more boost. This is where the EBC (Electronic Boost Controller) Comes in. The way my EBC, the Blitz, works is by breaking the line between the pressure side of the turbo and the wastegate with a solenoid that doesn’t let ANY pressure by until you are at (or very near) full boost 

See the diagram here:

So, to sum up the function of the EBC, it allows the turbo to spool faster, and also allows on the fly boost adjustment. The Blitz Dual SBC has 4 preset values that you can easily toggle between. I have 1 and 2 set up for low boost, 7 PSI for 1 and 9 PSI for setting 2 which I use for cold starts. 3 is my normal driving at about 14 PSI, and 4 is currently set a bit too high, so It works great on the roads, but on the highway allows too much boost, hitting my limiter set at 15 PSI, which turns the boost down temporarily.  This EBC also features a small tone warning so it will make a small beep if you hit boost above whatever you have the limiter set at. 

My only problem with this controller is that it is tuned, somehow, based on maximum available boost, so if your turbo is capable of making 28 PSI with the wastegate fully shut, and you want to run 14 PSI, instead of programming in 14 PSI, you tell the controller you want 50%. So if you don't know the maximum boost the turbo makes, you have to play games adjusting the percentage trying to find the boost you want. For me I was aiming for 14 PSI, which is about 62% of my maximum boost.