What is the (mechanical) reason for turbos to blow and why are K04s different?
10-08-2006, 09:25 PM
#2
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they can "blow" for various reasons.....
stock K03's usually blow because of the following reasons:
-increased oil temps due to the not so great oil feed line on the passenger side running very close to the exhaust manifold
-overspeed causing a fin to burst on the turbine wheel, this will then cause out of balance, premature bearing wear, ect...
-hot shut downs, not warming them up before WOT, ect...
The larger compressor wheel is the main reason for the K04's higher reliability. This leads to less oil starvation issues at extreme shaft speeds, lower heat, and higher efficiency on of the compressor wheel.
-increased oil temps due to the not so great oil feed line on the passenger side running very close to the exhaust manifold
-overspeed causing a fin to burst on the turbine wheel, this will then cause out of balance, premature bearing wear, ect...
-hot shut downs, not warming them up before WOT, ect...
The larger compressor wheel is the main reason for the K04's higher reliability. This leads to less oil starvation issues at extreme shaft speeds, lower heat, and higher efficiency on of the compressor wheel.
10-08-2006, 09:27 PM
#3
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My understanding...
from what I have been told the shaft speed often can have the finger pointed in it's direction. Now first understand that turbos are consumables. At some point, regardless of what you have given their nature they will not last forever. Anyway, the KO3 have a smaller compressor shaft than a KO4. The result is higher shaft RPM's. These can exceed 200k rpms!!!! Chipping obviously increases this shaft speed. The KO4 has a larger shaft, thus reducing the overall speed the shaft spins. Creating less strain.
10-08-2006, 09:29 PM
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shaft sizes are exactly the same between the S4 K03 and K04.....
the compressor wheel is what is going to be the main determinant of shaft rpm, but you're correct in the effect that shaft rpm can have.
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10-08-2006, 09:40 PM
#8
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Thanks, i was alwyas surprised to see those things chewed up and didnt see how they would get
ubalanced. Does that mean that zero clearance turbines have a higher chance of getting butchered? Maybe it doens have anything to do with clearnace, its just closer to the housing so a slight deviation would be a problem I imagine.
What do you think?
What do you think?
10-08-2006, 09:44 PM
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For zero clearance the coating we use is an abratable one......
so if something does happen the coating will wear off instead of causing damage to the wheel or housing. BUT, unless there is some reason for premature bearing wear, then the wheel is not going to wear the coating anymore past the initail break in.
We, including myself, have taken z/c turbos apart after 50K+ miles and there has been no wear beyond the initial wear of break in.
We, including myself, have taken z/c turbos apart after 50K+ miles and there has been no wear beyond the initial wear of break in.