Loss of power from wastegate???

[Mackzero]

On the way home tonight, I suddenly noticed that the car was boosting around 4-5 psi lower than usual at WOT, and also heard what sounded like a big boost leak. When I got home I pressurized the intake of the turbo for a boost leak test. I put 50 psi in there and I do not have any boost leaks. I did not have time to do any further testing unforturantly.

Have any of you ever had a gasket of the wastegate (I have a Tial 38mm) blow, and a similar loss in power?? Any help is appreciated. I also checked the hoses for the Tial, upper and lower, and they are fine.

 

[Mackzero]

I just went out and looked this morning, and BOTH of the SS bolts that the Tial came with to hold on the Dump tube FELL OUT!! I can't believe I did not notice it last night. That explains the noise like a boost leak.... Now would that cause a loss in boost pressure though??

 

[Ian M]

The dump tube should not have a effect on the boost,however if the bolts that mount the WG itself (to the manifold,o2 etc) have also come loose,that would create your problem.

 

[Mackzero]

I forgot to update. Yes, that was the problem. New gaskets/bolts and it's good to go again. This post was a waste of space, sorry. I should have looked at everything closer before posting.

 

[oldman]

Did you put lock washers on the bolts this time?

 

[Mackzero]

There were lock washers on them last time. The ones that fell out, were the ones that came with the wastegate. I'll keep a more closer eye on them this time.

 

[99gst_racer]

Have any of you ever had a gasket of the wastegate (I have a Tial 38mm) blow, and a similar loss in power??

Read through this thread and any links in it.

I've also had my gasket blow out and then the wastegate became loose. I had crappy idle and my car sounded like a 30 year old 454 with a huge exhaust leak. Also spool was slow as hell and it wouldn't reach full boost.

If you have any doubt in you WG gasket or that fact that it may be loose, check it.