life even worse for ya
..note: in every case, the overall power of the car remained about the same as it built up proper boost pressure at some point throughout the revs. In cases 1 or 2, it is very noticeable while chipped and can result in the turbo(s) dying even earlier. But regardless, they'd be destroyed anyway under the stock chip. The first two cases have been due to the impeller shaft warpage.
1. Higher pitch than normal turbo spooling sound. Almost sounds similar to a high pitch dentist drill. Witnessed this on the passenger side turbo.
2. An in-and-out wailing type sound of the turbos spooling. Very noticeable while chipped. Witnessed this on the passenger side turbo.
3. Major amounts of oil leaking into the intake side. Witnessed this on the driver's side turbo in two cases.
4. A very inconsistent dyno plot. Power and torque are built later in the rpm range(typically around 500 rpm+), and then they both die off earlier and much more rapidly as the revs max out (typically around 5k rpm).
One of the best ways to diagnose this has been to plot boost pressure versus rpm for the particular engine computer and then compare it to a healthy car. I looked into checking actual versus requested boost, but this has not shown anything. My friend and I were talking last night, and you'd think that the ECU would recognize that the boost is not building according to when it was desired and you'd want to set a fault code. Oh well...didn't/doesn't happen.
hope the descriptions helped a bit...here's a typical case...green is good (notice how the boost comes in earlier) while blue is bad (boost comes in late)