Started thinking about this a little more now, scary I know!
I vacuum solenoid/servo (double acting cyl to be exact) might be in order to maintain the minimum geometry position for the housing. Flip a switch and its exhaust brake mode!!
Then I can tune the minimum geometry position for maximum spool up and not have to worry about choking the engine out.
And I had another thought..... even MORE scary!!
What about using a doubling acting cyl using drive pressure to open the veins and boost pressure to close the veins.
When drive pressure is higher than boost pressure, the veins would open and allow drive pressure to decrease bringing the system to equilibrium, boost psi = drive psi.
When boost psi is higher than drive, the veins would close, causing drive pressure to build and once again bringing the system to equilibrium along with spooling the turbo faster.
Follow?:bang
Thoughts?
what would you use to bring the veins back to rest?.... I believe when you release the throttle both boost and drive pressure go away and that leaves the veins were they are since there is still equilibrium..... Am i wrong?
LOL forgot about that one. Maybe a spring inside the cyl. So it would be a double acting cyl w/ spring closure. Have to balance the spring force so it could pull the veins shut but still allow the drive pressure to push against it...
Started thinking about this a little more now, scary I know!
I vacuum solenoid/servo (double acting cyl to be exact) might be in order to maintain the minimum geometry position for the housing. Flip a switch and its exhaust brake mode!!
Then I can tune the minimum geometry position for maximum spool up and not have to worry about choking the engine out.
And I had another thought..... even MORE scary!!
What about using a doubling acting cyl using drive pressure to open the veins and boost pressure to close the veins.
When drive pressure is higher than boost pressure, the veins would open and allow drive pressure to decrease bringing the system to equilibrium, boost psi = drive psi.
When boost psi is higher than drive, the veins would close, causing drive pressure to build and once again bringing the system to equilibrium along with spooling the turbo faster.
Follow?:bang
Thoughts?
Will one of these pneumatic actuators hold up to the heat of the drive pressure?
I had thought of using the double acting also, with manifold pressure on one side and drive on the other, but you would need a spring to bring the veins back to the base set point.
What do guys use in their twins setup where they use drive pressure to actuate an external wastegate?
Also what did you use for the down pipe flange?
i though external gates are actuated by boost.
Garrett
Most of them are, but I'm pretty sure there are some that use DP to keep the gate closed and then Manifold pressure to open it.
Don't know on that one... Maybe they're built to take the heat since they are usually mounted directly to the exhaust manifold??? I just used the dp from my HX40; I have a 400 series but I'm sure the 300 series are the same.
I had a sudden epifanie over lunch on this matter....
Have a 4 port 3 way valve/solenoid to direct vacuum to the port that was driven by drive pressure. Suck that baby shut!
Yea?