Boost vacumn pipes location

[killerjamo]

Hi there I have done a top end rebuild to my legnum and haven't got a clue where vacumn pipes go and not getting any boost pressure ? Not sure where boost pipes go from boost solenoid to wastegate and same for fuel pressure regulator

Ian

[Confused]

Hi Ian,

Here's a selection of images of the boost vacuum pipework schematic from different perspectives - hopefully you can figure it all out from this combination of images!

VR4 Auto pipe work.jpgVR4 Factory Plumbing.jpgVR4 Vacuum Plumbing Diagram.jpg


Garry

[Davezj]

Ian, the first pic is where the pipes go roughly in the engine bay.

i will say though these picture are for a pre factlift (PFL) car with traction control as you can see the vacuum tank and solenoids associated with the traction control.

just to make it a little easier to understand i have marked the boost pipe that goes from the inlet elbow that fits to the throttle body, to the first T piece , then to second T piece that splits the boost pressure to the front and rear wastegate actuators, the first T piece goes off to the boost solenoid then from the boost solenoid out to the inlet pipe work for where it is just dumped back into the inlet airflow.
The factory boost solenoid bleeds off boost pressure it does no sit in line with the boost pressure that goes to the wastegate actuators.

VR4 Auto pipe work with TCL 2.jpg

I use this analogy to explain the operation of the factory boost control system.

Think of it as a water pipe with two taps on it one at the end and one in the middle.
you have the first tap at the end of the pipe fully open with water gushing out at max pressure.
if you turn on the middle tap it will bleed off some of the water pressure and end tap will have less water pressure and less flow.
the more you turn the middle tap on the less water flows out the end tap.

the end tap is equivalent of the wastegate and the middle tap is the equivalent of the boost solenoid.