whats bcs?

 

boost control solenoid. Its a small part that controls the boost located on the left side of the engine bay under the intake i believe near the coolant overflow tank

Actually ill make a write-up on this for us to have

 

I always thought 12 psi was stock?

Oh, and all this info coulda come from google. Search next time.

 

Here is the write-up i just did on it
https://mitsubishiforum.com/m_215082.../tm.htm#215082