Ed and John,

So this brings us to what do we do now?

Test 1: install new modified turbo! Check MAP to see if he is still producing to much boost.
I believe he should get some ramp-up of boost and it appears he is making to much.

Test 2: put a spacer in between the back cover of the turbo and the turbo, where the wastegate is located.
this will allow the wastegate to open farther.

Test 3: Remove the wastegate all together.

Test 4: Find a more suitable turbine wheel.

Bob

On Jul 12, 2004, at 12:45 PM, Ed Anderson wrote:

1. we could have a condition whereby the turbine was not in the "overspeed"
territory but operating at a lower (safer speed) and a condition existed
that build up a deposit on the turbine wheel until its out of balance state
caused it to touch the housing and fail.

2. A worn bearing ultimately resulted in failure due to wobbly and wheel
contact (Possibly acerbated by periods of long boost at high speeds - but,
not a true overspeed condition)

3. Overspeed of the rotating assembly resulted in failure (due to operating
too far to the right on the compressor map possibly acerbated by the leak in
John's intercooler and/or BOV valve).

4. Defective weld of wheel to shaft (Pretty remote chance - I believe -
especially with two turbos)

5. Some combination of the above. But, I believe that in all cases higher
turbine speed would acerbate the condition and lead to quicker failure -
whether true overspeed or not.

Good addition to the theory stack, Bulent.

Ed