Quote:
Originally Posted by Boxstard
It does not take much imagination to predict relatively poor gage R&R with dry torque vs lubed... My point was to clarify if the spec is meant for lubed or dry condition.
If you lube and torque to the dry spec., it will be over tightened, it's the fact. Still you may have no issues if the clamp force is still under the material yield, which could be the most cases where components are designed with safety margin, especially Porsche.
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The entire point of the ARP paper was to demonstrate that you cannot reproduce the intended clamping force without proper lubrication. The torque spec is to get that clamping force level, which you may, or more probably may not get when applying torque to dry fasteners. In their research, ARP looked at the actual achieved clamping load vs the observed torque readings; when the fasteners were torqued dry, the clamping load was all over the place; sometimes high, more often too low. When lubricated, the specified torque readings uniformly produced the expected clamping loads.
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