Quote:
Originally Posted by Rederic
Wondering the same thing –
I’ve been attempting to control boost with a bleed type controller… Not having a lot of luck considering the size of the wastegate actuator hose in the length to the controller bleed valve…
Thinking about switching over to a ball and spring…
Concerned about the need for a cooling bypass air
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I used a ball and spring type controller on my 760 for a while. It didn't suffer any negative effects although I had to make sure the plumbing parts were all large enough to work with the unusually large air signal hose.
In theory there is a way to take the wastegate actuator assembly apart and shim the spring in there to increase the WG opening pressure. But that would be a lot of work with the trial and error to get to the desired pressure.
However -- I think one key is that you only need the cooling bypass air once the WG has begun to open and exhaust is flowing hot across the WG valve. If the WG is kept completely CLOSED by the use of a ball and spring, then the valve is in contact with its seat and can transfer heat there plus it's not exposed to continuous flow of hot gas.
This was my logic at least in believing the common ball and spring type controllers would be fine for this type of turbo, as long as the plumbing (and the ball and spring themselves) were sized large enough that once air does begin to flow to the WG, it can flow at a high enough rate to help keep the parts cool.
I hope my speculation is right.
