Is this repairable or usable as is?

 

Depends if the diafram inside is broke or not.
Hook it up to a vacume and see if it works?

 

How does that show? Could I use an A/C vacuum pump? Then what does it do if it is good or no good?

 

Just pump 40 psi of compressed air to it......see if the rod moves.

 

A $25 boost elbow does the same thing...

 

Uh, no it doesn't. A boost elbow is just a leak. It lets the boost spike but it will eventually drop down to the wastegate. A manual boost controller works well, though.

 

I totally knew that

 

Mine looks like that after trying to force the turbo on the studs with the wastegate hitting the motormount. It damaged something inside because now the WG is stuck open and I had to clamp off the hose to keep from losing all my boost.....