I have a basic understanding of turbocharged engines in general, and I started diving into the Evo IX's (since it helps to know details about your car). After doing some research online, I thought I was good to go... But then I came across the Evo IX supplement I downloaded a few years back and saw the diagram of the Engine Control System, and, needless to say, I just got overwhelmed by the damn thing...

My IX is still stock with a few miles under 15K on it (a lot of business travel), and I'm finally getting the bug to mod it.

I'm curious to know how this diagram will look after light or heavy modding (i.e. upgraded turbo, ext. wastegate, MBC, upgraded BOV, etc.).

Also, can somebody explain the segment going from the engine to right before the inlet of the compressor?

 

Even after upgrading whether it be light or heavy modifications all of the vacuum line will be ran nearly identical except for the manual or electroinc boost controller. The new boost controller will take place of the stock solenoid in the diagram.

And im not understanding your second question fully. If u mean explain what it is, its showing u how the air is routed from the turbo to the engine. The huge thing above the engine is suppose to represent the intake manifold and following it toward the turbo the back shaded box should be the ic. And in between the two its showing thae vacuum for the blow off valve or diverter valve and how it routes back before the turbo when recirculated. Its actually not hard to comprehend all the vacuum lines and such if u eliminate the things with stars beside them. Those are just sensors so no need for them if ur only looking at the vacuum lines. But all of the wastegate lines blow off valve lines and such will be almost identical and will have detailed instructions with illustrations in them once u purchase them.

 

Thanks for the followup awdordie.

Here's the portion I'm talking about pointed by a red arrow for my 2nd question.
Is air flowing to the engine or is it flowing from the engine to the compressor inlet?

 

that is the line that goes from the intake tube to the breather in the rocker cover.

 

+1. Its a vacuum line that keeps pressure out of the valvecover. It doesn't need to be hooked up for the car to run properly but it should either have a filter or more preferably an oil catch can tied in to prevent oil from getting everywhere.