Strut Tower rip

[Bernie Benz]

> From: Ken Keith <auditude at gmail.com>
> 
> On Thu, 27 Jan 2005 11:25:20 -0800, Bernie Benz <b.benz at charter.net> wrote:
>> 
>>> From: Ken Keith <auditude at gmail.com>
>>> 
>>> What I was recently wondering is if 2Bennett would have an opinion
>>> about a Bernie Brace being used in conjunction with their Revolution
>>> camber/caster plates.  If both are used, do the plates see more stress
>>> than if they are used alone?  <snip>
>> 
>> Several problems here, Ken.
>> 1. The 2B plates provide no more camber adjustment than stock, unless you go
>> with a smaller diameter upper spring perch and springs.
>> 2. The 2B plates do not provide independent camber and castor adjustment,
>> change one and you alter the other.  Poor design for the money!
> 
> Okay, so those are criticisms of the camber/caster plate.  I guess I
> don't see how those really speak to what I was asking.  It does make
> your opinion known, again.
And just what were you asking?
> 
> It's slightly interesting how people with on topic, but previously
> answered, questions are sometimes sent to the archives to find the
> answer, but in other situations like this we get to hear the same
> opinions as have already been posted, without even asking for it.
The diff between a newbe and old timer.
> 
>>> <snip>Let's assume the 2B plates are
>>> in place for alignment purposes, would the Bernie Brace be any more
>>> effective or efficient than a brace acting on the sheet metal of the
>>> towers?
Is the former stiffer than the latter?  Then, yes.
>> 
>> 3. Eliminating the strut rod isolation may be OK for the track, but I
>> wouldn't have it for a street car. My brace retains the isolation while
>> distributing the upper lateral cornering force equally between the two
>> towers.  Absolutely and theoretically the best that one can do, without
>> tower redesign.
> 
> Well for any "best", isn't there still a compromise?  You may put a
> certain level of importance on the isolation offered by the stock
> piece.  Someone else may consider that less important, and have a
> different "best".  I suppose it could matter what streets, and tracks
> for that matter, that you will be driving the car on.  I think we
> covered some of this with the track car thread.
You missed the point here, Ken.  Maybe because my explanation lacked
clarity. For the purpose of this discussion, the upper suspension lateral
stiffness can be considered to be two different spring systems in series,
the isolation system and the tower system.

You could, 2B did, eliminate the isolation to obtain infinite stiffness of
this component.  I chose to retain the full stock isolation capabilities but
I increased the stiffness of the isolation system by 2X+ by paralleling and
preloading the two isolators in the latteral direction.

The stock tower spring system employs only one of the two towers at a time,
one for each direction of latteral force.  My "Absolutely and theoretically
the best that one can do, without tower redesign." statement referred only
to this tower spring system, not the isolation.  The purpose of a tower or
strut brace is to share some of the lateral force between the two towers.
Minimum tower deflection occurs when this sharing is equal, requiring that
the brace be on axis with the latteral force and an order of magnitude
stiffer than the towers.
> 
>> 4. It's all a matter of total system stiffness, Ken. To be effective, any
>> brace must be an order of magnitude stiffer when installed than is the
>> system it is stiffening.  Mine is, and light weight. I've never seen a tower
>> brace that comes close to meeting this criteria, even after removing the
>> isolator from the system, as 2B did.
> 
> I think the brace you designed is cool.  I'd like to have one on my
> car.  I won't try to disagree about what is stiff enough or not stiff
> enough.  I will say that intuitively, something being there should be
> stiffer than nothing there.  As far as stiff enough, that depends on
> stiff enough for what and for who.  I guess you're saying your brace
> is stiff "enough", and anything different or additional is going in
> the wrong direction?
> 
>>> It seems like what I've read indicates that the towers can dance
>>> around all they want and what really counts is the strut alignment.
>>> This makes me wonder if the overall chassis dynamics would be improved
>>> by a stiffening of the towers themselves.  Say, if the chassis/body is
>>> twisting.  The Bernie Brace might make the front tires themselves be
>>> in the right position, but would a strut tower brace reduce some of
>>> the overall chassis flex (trying to describe something different than
>>> a tire alignment issue), such as when you jack up the corner of the
>>> car and the doors become hard (and/or a bad idea) to open?
You're talking sky hooks and hokes pokus here.  Let me know when you find
one.

Bernie
>> The upper suspension is referenced to the chassis through the towers in all
>> cases, short of major chassis redesign.
>> 
>> Enough dreaming, reality reigns!
>> 
>> Bernie
> 
> Oh, okay.  Never mind then.
> 
> Cheers,
> 
> Ken