EVOEMS

I have heard this term and understand what it is. My question is, what causes a turbo to go into an " overspeed" situation? Thanks.

BluEVOIX

iTrader: (69)

Simple 2 things can cause that:

1. Setting boost way way over the turbo's efficiency range or pretty much leaving the wastegate shot.

2. Boost leak. If your car has a boost leak then your turbo can be over working to create the pressure that you set the mbc to run. So in order for car to reach the goal of X pressure set, it has to over work the turbo to overcome the loss in pressure as well as reach the target.

But there is a certain point in which no matter how much you try to raise the boost the turbo cant push more air because it simply runs out of breath. And with efficiency range I am speaking of the point in which the turbo no longer creates use-able power.

Aby@MIL.SPEC

iTrader: (161)

a majority of the time, it happens when an ic pipe comes off during high revs / max boost......with the pipe blowing off, the turbo just free wheels.....imagine you clutching your engine when 7000 revs in 4th gear........what will the engine do? it will over speed, just like a turbo will when the ic pipe pops off during high revs / max boost.

if you went up in altitude, you can experience it there too.

EVOEMS

Thanks, I appreciate the info, I had an issue that I am trying to diagnose. No ic pipe failures, no boost leaks and no vacume or exhaust leaks. The turbo was not overboosted nor subject to any oil starvation issues. I am wondering if there was some kind of initial bearing defect? With all of the IX turbos and IX based aftermarket turbos out there, ther must be a few that will have some kind of initial defect. I will keep doing the research.