How Subaru’s Factory Boost Control System Works

[Christian.]

How Subaru's Factory Boost Control System Works v1.09
This document has been created to teach you how the factory boost control system works in all turbo-charged Subarus, 2002-2007. Information about how the vacuum lines are plumbed, where the "T" is located, how the individual components function, etc. are all covered in this document. I will be happy to answer any questions you may have.

Updated 04/02/2007 - We have revised the document to v1.06 and we have included some plumbing instructions for external wastegates and 3-port boost control solenoid valves.
Updated 04/17/2007 - We have revised the document to v1.08 and we have included some plumbing diagrams for various 2 and 3-port boost control solenoid valves. These diagrams should be very helpful when you are trying to figure out which vacuum lines go where
Updated 04/24/2007 - We have updated some of the diagrams to include more specific information on the 3-port EBCS solenoid valves, updated to v1.09.

Take care,
Christian.