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More..Upper stress bar questions



here we go again overthingking and over engineering ideas ....

larry, I put it in because it COOL, does that satisfy your questions...

(so fsken sorry debates like this exists)

==========================================
ATS - Patrick Bureau
1985 8v **Planning 3A/JH  Upgrade**
1988 16v ** Euro Project/maybe 8v **
Web Site : http://longcoeur.com/scirocco


=>-----Original Message-----
=>From: scirocco-l-admin@scirocco.org
=>[mailto:scirocco-l-admin@scirocco.org]On Behalf Of Larry
=>Sent: Saturday, June 15, 2002 9:07 AM
=>To: Cmr446@cs.com; scirocco-l@scirocco.org
=>Subject: Re: More..Upper stress bar questions
=>
=>
=>After reading recent posts about rear stress bars, I started thinking
=>(uh-oh...).
=>Does that item actually perform a useful function?  Oh, I know many of you
=>report impressive handling improvements resulting from the installation of
=>one, and I was seriously considering putting one in my own roc.
=>But, after
=>looking carefully at the rear suspension design, I don't believe
=>they can be
=>of much benefit.
=>  Yes, they certainly minimize the movement of the rear
=>damper/spring unit's
=>upper mounting points, but only in one plane, that plane being directly
=>towards and away from each other (>< or <> aka the x-axis).  The big
=>question is:  what stresses would make these two mounting points move
=>together/apart?
=>   Lateral forces from cornering are completely absorbed by the rear axle
=>mounts (axle-to-floorpan). No lateral stresses (x-axis) can be present at
=>the top of the damper/spring units because these units are attached to the
=>body and the rear axle with flexible attachments.  When the rear
=>axle moves
=>slightly sideways during cornering, the damper/spring units just pivot
=>slightly in their upper and lower rubber bushings and absorb this
=>movement.
=>The bottom of the d/s unit moves in the x-axis with the axle, but
=>it pivots
=>on the mount, therefore it cannot transfer x-axis forces to the top of the
=>d/s unit. (Okay, it does transfer very small amounts, because the mounts
=>have some stiffness, some resistance to that flex, being made of rubber or
=>polyurethane.  If the mounts were Heim joints, there would be
=>zero transfer
=>of force).
=>
=>The only significant stress on the upper mount (at any time) is in the
=>z-axis; a VERTICAL direction (^), which the stress bar cannot control.
=>I realize that this may unleash a flood of responses telling me
=>how wrong I
=>am, but before any of you do that, be sure you can back up your
=>postion with
=>more than "Hey, all the racers use 'em and they can't all be wrong!" or "I
=>put one on my car and could really tell the difference."  Those are not
=>valid, defensible engineering positions.
=>
=>Any thoughts?
=>Larry  sandiego16V
=>
=>----- Original Message -----
=>From: <Cmr446@cs.com>
=>To: <scirocco-l@scirocco.org>
=>Sent: Saturday, June 15, 2002 12:28 AM
=>Subject: Upper stress bar questions
=>
=>
=>>   I need opinoins or reasons on which is the better design for an upper
=>> stress bar;
=>> the solid type like the Eurosport, Neuspeed or ABD model, or an
=>adjustable
=>> one like the Autotech bar.
=>> Carl
=>> 77rocco
=>> 89fox
=>
=>
=>
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