Go Back   986 Forum - The Community for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Performance and Technical Chat

 
 
LinkBack Thread Tools Display Modes
Prev Previous Post   Next Post Next
Old 06-11-2011, 10:20 PM   #22
Certified Boxster Addict
 
Join Date: Nov 2010
Location: Los Angeles
Posts: 7,669
Quote:
Originally Posted by insite
How many g's do you think are exerted outward by centripetal force at the edge of a flywheel turning 7300 rpm? 100? 1000?

Try ELEVEN THOUSAND THREE HUNDRED. 11,300g at my redline. That means 17grams becomes 425 lb. Over time, that wobble can absolutely fatigue the crank. It's not forged, it's sintered.

My point is that the crank won't fatigue because the force (your calculation of 425 lbs) is far below the fatigue load. This situation isn't like bending a paper clip back and forth until it breaks. This load level is more like me trying to bend a street light post. No matter how long I push on it (months, years, decades), it ain't never gonna break.

This is why owners can drive around with a failing DMFW for thousands of miles (which produces 100x the force of your example LWFW) and everything is still ok.
__________________
1999 996 C2 - sold - bought back - sold for more
1997 Spec Boxster BSR #254
1979 911 SC
POC Licensed DE/TT Instructor
thstone is offline   Reply With Quote
 



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 05:41 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2025 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page