What is the cause of a blown turbo?
09-26-2004, 08:42 AM
#7
Manufacturer defect, poor QA run.... don't forget!!! Larger turbos usually don't deal
with as much heat as they are more efficient, thus they are producing more boost then heat, it's when you go out of the efficiency range do you start creating more heat then boost.
However the S4 turbo failures happen at a greater rate then most cars, that's due to manufacturing problems, then maybe a subpar oiling system in the Audi.
However the S4 turbo failures happen at a greater rate then most cars, that's due to manufacturing problems, then maybe a subpar oiling system in the Audi.
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09-26-2004, 08:46 AM
#8
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how do you measure the life of a turbo?
what are signs of it about to go? Would a car with a lot of highway milage have a worn turbo or a car that was driven hard with less miles?
09-26-2004, 08:49 AM
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not enough good oil
I ran my '87 saab 900T over 200k miles on the original garret turbo using mobil 1 10w30. I ran 18-20psi for the past 4-5 years while stock boost is 12psi. I took it apart for a rebuild and was surprised the internals looked great. No black sludge buildup or anything. It failed due to the oil seal design on the turbine side of the shaft. I'm very confident it would've lasted much longer using turbonetic's new overlapping seal design. The seal (similar to piston ring) has sharp edges at the ring gap that eventually gouged a groove in the turbo housing. Once that groove was there I couldn't rebuild it. For comparison.. I replaced a guy's turbo in his volvo 740. The entire turbo was full of black sludge and hard carbon. The oil feed line had about 3-4 inches of slugde fall out! He said he hadn't changed the oil in at least a year. No wonder! I realize S4 turbos aren't the same but I'll bet the basic theory applies.
dave
dave