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Old 01-14-2012, 06:50 AM   #59
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Join Date: Jun 2010
Location: Socal
Posts: 4,025
My Ride: 1000rwhp Turbo M3
Originally Posted by Rockyminator View Post
What does the hub shim do?
There are two tabs on the rear of the exhaust hub...these tabs are what rattle around...over time these tabs can break...the shims increase the clearance and reduce the forces exerted on the tabs so that they will have a less tendancy to break as there will not be the larger distance for movement to occur.

Here's a pic of two hubs with broke exhaust tabs...

1000+RWHP, Lab22 Built Turbo S54 - BMW Half Mile Record Holder
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