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      07-28-2009, 05:03 PM   #26
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Drives: F90 M5
Join Date: Oct 2006
Location: Chicago

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100% correct. Although the differential may generate enough heat to damage or wear the CV boots on it's own, my intention with placing heat shields on our connecting pipes was just to make sure that the pipes were not contributing to any damage caused.

This makes me sleep a bit easier at night.

Originally Posted by lucid View Post
Thanks for the info. So, it sounds like this happened on an E92 M3 racecar pushed hard without a shield in that area of the exhaust. There are sevaral things going on at the same time: heat is being transferred to the joint via conduction from the diff; heat is being transferred to the joint via convection from the exhaust pipe (can be significant when the car really slows down and/or comes to a stop after running hard and there is no forced convection but a really hot pipe briefly, or in any other situation when flow is interrupted); heat is being transferred to the joint via radiation (although the magnititude of this effect appears small, when combined with the other heat transfer modes in extreme driving conditions, it seems that it indeed does make a difference in overheating a rubber part). Placing a shield obviously does not do anything to reduce conduction from the diff, but blocks radiation and reduces convection from that section of the pipe.