Compressor Surge Anyone? (Vid)

[Def]

Originally Posted by hellaflush

^^^ wtf?

and to further put fact towards the myth... all it is, is the charged air bouncing off the closed TB back through your pipework and being cut by the blades going the other way...

yes air can erode stuff - over 100's of years... and steel is a bit more sturdy than rock etc

Do not post misinformation.

Compressor surge is the compressor wheel aerodynamically stalling since the massflow through it drops too low for the flow to stay attached for a given pressure ratio. It has nothing to do with "air bouncing" and being "cut by the blades."

It's not that it "erodes" anything, it's that the wheel doesn't stall uniformly, so it will axially and radially load the CHRA bearings, and in extreme cases can cause the compressor wheel to disintegrate.

Obviously Garrett builds its consumer grade turbos "stout" enough such that they can handle the stress in the wheel, and while the bearings wear faster it is not the end of the world. The wheels would flow more and spool faster if they were thinner and weaker, but they have to survive destruction testing at some multiple of what they think the wheels would ever see in normal use. That said, a recirculated BOV/BPV will keep the turbo spooled up better than with valve and surging the wheel(it slows down very quickly as you can hear from the vid).

Fighter jet engines blow up from time to time just due to pressure variations across the compressor face introducing vibrations across the blades since they are more "bleeding edge" than a consumer grade turbo.