External Gate, what am I missing

[aminga]

So I'm trying to expand my knowledge base on Turbo cars and understand using a manual boost controller gate Several people have posted the diagram of the turbonetics boost controler and an external gate.

And I'm just having a hard time with that diagram. You have manifold pressure to the bottom of the gate trying to open it. You have the controller in the line to the top of the gate so when boost hits a certain PSI the spring loaded valve opens and applies boost to the top of the gate, closing it.

Seems like it should be the other way around with the controller to the bottom.

 

[Mike E]

Typically when you run a controller, you run the lightest spring available. Say the the spring on top of the gate provides the equivalent of 4psi of pressure. Let's say your goal is 15 psi.

You have 4psi (from springs) on top. Your regulator lets a max of 11 psi to the top. Any time the bottom side sees more than 15 psi the gate opens. What typically happens is that back pressure acts on the bottom of the gate valve trying to push it open and you have to add more regulator pressure or spring pressure to counteract it.

Maybe you already know this, but on the external gates, the valve moves up into the gate housing. Looking at your picture above, the diaphragm has to move towards the port labeled "vacuum port" for the valve to open.

 

[aminga]

That's what I missed. I was assuming that the controller let zero pressure through until it hit it's target.

Pulled good until it blew the up pipe off though.

 

[huntsg]

So, I have a friend with basically the same set up as me (42mm external wastegate and a manual boost controller) and he doesn't hook anything up to the vacuum port just the boost port. Claims it spools faster that way. Thoughts?

 

[aminga]

This is on a buddy's car

I tried it with the top port open and it was slow.

 

[Mike Licht]

this is not a spring loaded valve that opens at pressure it is a simple air pressure regulator. You are putting full pressure to the bottom to open it and regulated (less) pressure on top to close it the differential pressure acts as a variable spring that controls boost pressure by determining how far the gate opens.

 

[TurboTnZ06]

One way to set it up is to bleed boost off trying to keep the gate closed. I run a 15# spring and apply boost to the gate to try to keep it closed. On mine it means I run about 18-19 psi boost at a minimum and can turn it up past 30 if I don't bleed any off and apply boost to keep gate closed. Result is that no boost lost in part throttle and spoolup is fast even if under stalled on the converter. Simple and seems to work, though once it is set I don't touch it.