RE: e30 "brace" ?

["Fadeev, Alex" <alex.fadeev@xxxxxxxxxxx>]

john [mailto:j.s.smith@domain.elided] wrote:
> 
> I've seen some adverts for what appears to be a "bracing bar" - a sort
> of strut that bolts across the top of the two front suspension damper
> towers. I suppose this "stiffens up" the front suspension in some way.

John, 
This is commonly referred to as a 'strut brace'.

> Is that its purpose? If anyone knows (I'm sure folk on this list 
> will), could you describe exactly what this means as far as handling
> in concerned. 

The primary purpose is that of an eye candy.
In theory, if the front subframe of your car is really soft, the tops of
your front strut towers could be floating all over the place during hard
turns wracking havoc with the front suspension geometry. In that case, such
a strut brace would keep the two strut towers tied together minimizing and
synchronizing their floating patterns. That's what strut tower peddlers will
tell you.
In reality, you will be hard pressed to find a modern car so poorly designed
as to come with this toy from the factory. E36 M3 LTWs did come with a
Motorsport designed hinge free strut brace in the trunk, but that was
commonly viewed as an extra reinforcement to be added _after_ welding the
front/rear strut towers into a common structure through a 8+ point race
cage. 
BTW, there was never a rear Motorsport strut tower brace as rear wheels do
little turning ;-). Rear strut tower braces are a total waste of money and
trunk space.

> Also, is such a strut a good idea for a road going (ie non-racing/
> competition) car?

Nope, it's a waste of money.
If you don't believe this, tie a string between the two strut towers with
minimal sag and see if it breaks. I could not brake mine until I started
autocrossing with racing tires. 

alex f

'89 325i
'95 M3

> Thanks
> -John
> ============
> '89 e30 325i
> --

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