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      05-22-2013, 05:02 PM   #17
Malek@MRF
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Drives: E92 M3, E46 M3, G82 M4
Join Date: Jan 2008
Location: Irvine, California

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Quote:
Originally Posted by aussiem3 View Post
What kind of load are we looking at for this type of failure? I am sure for a DD that sees the occasional track day this shouldn't be an issue. I think the way Malek described it, if you're consistently launching the car then I think you can anticipate this failure in combination with other mods such as lowers and adding spacers. I am prompting a discussion with this.
Both failures that have occurred on my E92 M3 have been during normal street use with moderate loads laterally. The car has never been launched or drag raced.

The main point here being that the differential and sub-frame deflect enough under lateral load on the passenger side to greatly affect half shaft pinion angle and cause the CV joint of the axle to wear. When analyzing the internals of the failure carefully, there were a lot of heat ligature marks found on the ball bearings, enough to make them out of round! Some of them were even scoured and the rest of them were simply lost because the CV joint exploded and they are now victim to a gutter somewhere on the street.

This axle failure occurred at 20 MPH loading the car up laterally, but not to any excessive amount.

Also, please keep in mind, if the car is lowered, this could further exacerbate the issue because lowering the car will slightly change half shaft pinion angles, and in combination with the excessive deflection that occurs on the passenger side, it can fail.
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