Hi there,

How is the wastegate controlled (opened/closed)? (Standard FD, no modifications).

Just been looking at a diagram of the vacuum/pressure piping (i.e. rats nest). The diagram shows 2 pipes coming from the oil injectors (dark blue), leading to a small manifold, which has 2 solenoids running from it controlling the wastegate and turbo precontrol actuators (I and J). The manifold also has a line running to the inlet side of the primary turbo. So when the solenoids switch, what is applied to the actuators to make them work? Vacuum or pressure? Seems a strange set up, not that I know anything about wastegate control anyway!

Thanks!

 

well,

without trying to make sense of that nasty vacuum diagram, I would say, in my case, my wastegate is controlled by my Greddy Profec B II boost controller

 

Okay I'm no expert on the subject but here's how I understand it...

Wastegates are the physical opening and valve inside the turbo's hot side that allow the exhaust to bypass the turbine wheel. Wastegate actuators are vacuum controlled and mechanically operate the wastegate valve by means of an attached metal arm.

If you look at the picture you posted, you'll see Actuator (Wastegate Controlled) that has two vacuum lines. The light blue line comes directly from a pressure source, in this case it looks like the y-pipe or turbo outlet. When boost reaches a certain point based on how stiffly the actuator is sprung, the pressure causes the arm to flip the wastegate open.

Notice the second line in green that goes all the way up to the solenoid. This line allows the ecu to control the solenoid to "bleed off" a little of that pressure, effectively increasing the spring rate of the actuator (or lowering the boost it sees, your choice) causing the turbo to generate a higher level of boost. When you install a boost controller, you cap those bleeder solenoids off.

Hope this answers your questions.