930 Wastegate Question

[johnman001]

I just recently (the last time I rove my 930) noticed that my boost is suddenly higher than I have ever seen. The needle now extends well to the right. It seems to have plenty of power, but it concerned me so I tried staying off boost for the remainder of the drive.

I decided that the wastegate must be sticking or some problem with it.

I looked in my manuals and it said to apply pressure to the hose leading to it from the intercooler (control line).

I rigged up a regulator and a gauge and applied pressure to the line.

At .8 bar (12-13psi) the valve seems to remain closed. At 1.1 bar the valve can be heard to open and close, but a hissing sound can be heard as air is escaping somewhere.

The car always used to run about .8 bar until now.

My main questions are:

1.) Is the diaphragm supposed to hold pressure, or do the y leak slightly?

2.) If I buy a replacement diaphragm from Lindsey Racing, where would I get a new gasket for the wastegate body?

3.) Would a leaking diaphragm be a cause for this overboost condition?

4.) I have seen the TiAL wastegates and believe one of them to be a direct replacement for mine, but I would rather attempt rebuilding mine than spending the extra money right now on a wastegate. (I did read that a rebuilt wastegate may be short lived, but I still want to try).

5.) Are there any other sources for a gasket and the diaphragm?

Thanks for your help/advice. I may try giving Imagine Auto a try since they are local to me.

John

[dean]

Originally posted by johnman001
I rigged up a regulator and a gauge and applied pressure to the line.

At .8 bar (12-13psi) the valve seems to remain closed. At 1.1 bar the valve can be heard to open and close, but a hissing sound can be heard as air is escaping somewhere.

The car always used to run about .8 bar until now.

My main questions are:

1.) Is the diaphragm supposed to hold pressure, or do the y leak slightly?

2.) If I buy a replacement diaphragm from Lindsey Racing, where would I get a new gasket for the wastegate body?

3.) Would a leaking diaphragm be a cause for this overboost condition?

4.) I have seen the TiAL wastegates and believe one of them to be a direct replacement for mine, but I would rather attempt rebuilding mine than spending the extra money right now on a wastegate. (I did read that a rebuilt wastegate may be short lived, but I still want to try).

5.) Are there any other sources for a gasket and the diaphragm?

Thanks for your help/advice. I may try giving Imagine Auto a try since they are local to me.

John

Did you hook the regulator to the control line for the wastegate? There is a vent also.

The diaphram isn't supposed to leak. However the valve guide will leak some and that is ok. A leaky diaphram will cause an overboost cond.

Imagine auto has the diaphram.

[mb911]

there are 2 tial units available that would fit the 930 let me know if you would be interested in either.. I can beet anybodies price

[johnman001]

Originally posted by dean
Did you hook the regulator to the control line for the wastegate? There is a vent also.

The diaphram isn't supposed to leak. However the valve guide will leak some and that is ok. A leaky diaphram will cause an overboost cond.

Imagine auto has the diaphram.

I put a regulator and a precision gauge in my compressed air line so I could determine the pressure it takes to open the wastegate.

The wastegate does not hold pressure or vacuum. I am thinking that the diaphragm is the leaky culprit.

I will try obtaining a diaphragm.



Are there any other gaskets in the wastegate housing?

Here is the only picture I found of the internals of a wastegate. Are there any missing parts?

[johnman001]

Originally posted by mb911
there are 2 tial units available that would fit the 930 let me know if you would be interested in either.. I can beet anybodies price

Sending you an e-mail....