No Boost is this the cause?

[ivanuf]

I am getting no boost. My first check is the waste gate. I aplied about 15-20 psi thru the lower port and have air blowing around the blue circle area of the photo.



Is my wastegate shot, is this the cause of the no boost condition or this is normal?

['76 911S 3.0]

Does the wastegate valve open when you apply pressure to the bottom port? If that were leaking, I would suspect you would have the opposite issue and be overboosting since the wastegate would not be opening.

[Pat RUFBTR]

When the rubber internal membrane is pierced that causes(provokes) a big pressure, we check(control) nothing more, the flight(leak) of air in your blue circle causes(provokes) maybe the opposite, anyway the wastegate never has to have of flight(leak) of air, you have to change the fibrous joint which is towards(at the place of) the blue circle.

[ivanuf]

Thanks for the help. I will install my Tial for now and put this on the to do list.

[reclino]

Looks like your gasket is blown between the hot and cold side. I was unable to purchase these new so made a small batch of gaskets, valve guides, and spring shims to make it possible to rebuild these wastegate's. http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/972314-930-wastegate-rebuild-nla-parts-2.html#post9898817