[200q20v] Re: Strut tower maximum lateral force

C1J1Miller at aol.com C1J1Miller at aol.com
Sun Mar 11 11:59:16 EST 2001

In a message dated 3/9/01 2:29:16 PM Eastern Standard Time, 
b.m.benz at prodigy.net writes:

> Dave, I stand corrected!  Thanks.  Why didn't you guys catch the error when
>  I first posted this back in July?  So, X my figures by a factor of 3 or 4.
>  Compression on the EMT is insugnificant, but the EMT must be straight to
>  prevent buckling failure.
>  Bernie

Here's what I'd posted back then...
Subj:   Re: Strut tower maximum latteral force.
Date:   7/7/00
To: b.m.benz at prodigy.net, gregsj at iea.com
CC: 200q20v at 200q20v.com, audi20v at rennlist.org

In a message dated 7/7/00 1:44:39 AM Eastern Daylight Time, 
b.m.benz at prodigy.net writes:

> The suspension geometery divides this force between the lower link and the
>  upper strut anchor point by the ratio of these two distances from the axle.
>  On the type 44 chassis, Axle C/L to ball joint C/L = 4", axle C/L to strut
>  piston rod anchor w/ a compressed suspension = 20".  Therefore 4/20 x 740 =
>  150lbs force.  This is  the theoretical, far out, maximum latteral force
>  that the strut tower will ever see!  (My strut brace further equalizes this
>  force between the two strut towers to 75 lbs max.)
>  Bernie

Bernie, I can see several cases where this value would be exceeded; including 
hitting a pothole (could get a lot more than .3 cf), especially in braking, 
with weight transfer, etc.

Doesn't really matter what the forces are; there is damage to a reinforcement 
for the tower, and later cars (S4/6) were sent from the factory with a simple 
bar strut brace.  My thoughts were just to use the factory parts, then add 
some form of adjustment.  

The worst damage we've seen is a crack in this webbing; doubt it would 
progress much further.  People should note that Bernie's car, with higher 
mileage, and his custom strut brace, does not have damage in this area; 
perhaps Bernie's brace is all that is needed.

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