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Rob 930 Rob 930 is offline
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Join Date: Dec 2002
Location: Seattle
Posts: 659
Thanks guys. I'm good at following directions, and that's just what I did with my Raceware studs. In fact, I went beyond that and talked to Raceware, for further clarification on how much overtorque is acceptable. But I don't want to blindly follow directions -- especially when there's such disparity -- without some understanding of what underlies the reasoning. I'd be surprised if a coating on the Raceware studs would account for the 50% difference from ARP -- but I'll try to find out. I have a hunch that the clamp load with the ARPs is higher, and if that's the case, I want to know why. As I see it, what matters here is not torque or even bolt stretch -- it's clamp load. And if each manufacturer is recommending a different effective clamp load, I'm concerned. I'm not sure I trust either stud manufacturer to be the expert on what the correct clamp load is for a particular Porsche engine.

This issue is particularly of concern for a turbo engine, where overboost is possible and head liftoff is sometimes an issue.
Old 09-20-2005, 07:19 AM
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