bebbetufs

How exactly does the inverter valve manage to use a diaphragm to open both under vacuum and under boost?

Paulyy

IS this what you're after?

Scott H

Simple answer: it doesn't open under boost, the boost pressure is helping to keep the valve shut during that time. It only opens on vacuum to divert excess boost pressure back pre-turbo.

blown 944

The diaphram is aided by the springs and pressure to keep it closed under boost. Then when vacuum is present it aids in opening against the springs. If the springs are light enough it could open under vacuum if the turbo (or supercharger in my case) overcomes/matches the spring pressure.

bebbetufs

If it does not open under boost how does it help controlling the pressure build up when the throttle plate is closed?

David Floyd

I think you are confusing the wastegate which controls boost pressure and the diverter valve which diverts excess boost pressure off throttle

bebbetufs

No, I'm only talking about the diverter. In this thread it is said very clearly that it operates both as a bypass valve, to allow less resistance to intake air when under vacuum by diverting air past the turbo, I assumed it uses vacuum to open in this case. Then it should also be able to dump excess charge pressure away from the compressor when the throttle plate is closed. This must be controlled by boost because by the time there is vacuum it would be too late would it not?

David Floyd

Vacuum line attached to the top of the diverter valve so vacuum is instant when throttle is closed

bebbetufs

Thanks. It took me this long to remember that vacuum is tapped behind the throttle plate.

chrisAl3

Hi guys, i wonder if you could me out here.
on my A3 if i am driving the car and boosting hard, lets say i dribe in 4th gear and put my foot flat, the car boost beautifully till about 4000rpm then it does not boost, almost like the diverter opens up, if i let go of acceleration and wait a few seconds and put my foot down again it boost again, then does the same thing? Any suggestions?