RB26 Boost Valve Solenoid

[Foszy]

RB26 Boost Valve Solenoid

Hey all,

Just a couple of questions about the stock boost/pressure control solenoid on the RB26. 

Am I correct in saying that the green tube, facing the front of the car, is the inlet tube (to the solenoid) and the blue tube, facing the engine, is the outlet tube (from the solenoid)?

If I block either of these tubes completely with a ball bearing will I run true wastegate pressure on the turbos and eliminate any pressure being bled and re-directed back through the system?

 

Cheers, Foszy.

[89CAL]

Think about what happens when you block either one of these tubes. What is that going to do?
You will stop any boost pressure reaching the actuator

What do you think happens if there is no boost pressure at the actuator?

If you want to run the wastegate spring setting for boost, all you have to do is run a boost line directly through it (bypass the solenoid)

[Foszy]

12 hours ago, 89CAL said:

Think about what happens when you block either one of these tubes. What is that going to do?
You will stop any boost pressure reaching the actuator

What do you think happens if there is no boost pressure at the actuator?

If you want to run the wastegate spring setting for boost, all you have to do is run a boost line directly through it (bypass the solenoid)

If I block either tube directly at, or close to the solenoid itself, how does it block pressure from reaching the actuators? From what I gathered a nipple from under the rear of the intake plenum feeds the actuators boost pressure and the solenoid is hooked up in this hose system to bleed around 2psi from this "green" set of hoses, through to the "blue" set which is redirected back to a pipe on the second turbo (pre-intake). 

If I just connect the two tubes (going into the solenoid) and bypass the solenoid, wouldn't it just continuously bleed the boost pressure back through the second turbo and never allow enough to get to the actuators, and result in infinite boost to be built up? 

I was going with the idea of removing the stock boost restrictor allows more pressure to be bled back through the system, so having a smaller restrictor would result in less being bled, and as a result, having it completely blocked would mean wastegate spring pressure would be used?

 

Edited December 13, 2016 by Foszy
insert line break

[89CAL]

The solenoid completes a circuit. (As per your pic above) If you block either tube it will not act on the actuator. If you join the two tubes at the solenoid (bypassing it) you will run wastegate pressure

Just join the lines where they start to go around the back of the engine

[Foszy]

10 hours ago, 89CAL said:

The solenoid completes a circuit. (As per your pic above) If you block either tube it will not act on the actuator. If you join the two tubes at the solenoid (bypassing it) you will run wastegate pressure

Just join the lines where they start to go around the back of the engine

Yea, that's what I thought judging by that diagram, as it just shows the solenoid tubing, but then on the vacuum diagram you can see that the plenum feeds the actuators boost pressure and the solenoid breaks into the tubing and bleeds/redirects some pressure back through the intake of the second/rear turbo (as also shown in the second diagram). If it was like this and I connected the two it would just bleed/redirect everything to pre-turbo.

I coloured the corresponding tubes in another diagram of how it seems it's actually set up, apart from it getting boost source from the compressor housing instead of the intake plenum.