Originally Posted by
Wrench_Si
Its caused by the pressure pushing back on the compressor wheel and stalling it out. But in some cases it can happen so fast that it can actually destroy the bearings, wheel and possibly the shaft itself.
Most common though is the thrust bearing being damaged/destroyed.
This happens when you let off the throttle and the BOV doesnt allow pressure refief thus building excessive pressure againts the wheel.
This is the right answer. We talked about it at VT. With the fmic, the turbo has to fill the piping and ic, as the bov vents the turbo is still spinning and building pressure in the system as it creates enough to allow the bov to vent and not enough air was released the 1st time causing the compressor wheel to stall suddenly. This does increase turbo wear. If you don't believe it, call the turbo companies yourself. It is more common in journal bearing turbos. I've seen more issues with the Greddy's and HKS's The HKS's also rub the hood on cars with tmic's. I've seen 4 STi's with holes rubbed through the inner frame of the hood and 3 WRX's done the same way.
Without running a full stand alone, the AP is your best way to go.The Utec or any other piggy back does not have as many options as the AP. Yes, some ecu's do crap out over time. I've yet to see the AP be the cause of it unless you were improperly using the AP. Even after that, you just have to send your ecu and the AP back to Cobb for them to fix it.