Group Buy-BSI stayrod for A1 chassis

[PhilipM3@tiac.net (Philip P. Mueller III)]

> ...but what gets me is that there IS NO fore/aft motion under
> acceleration. The engine has purely
> torque (rotational) movement at any time. The engine isnt pulling
> the car forward, its turning the
> wheels, which force the a-arms forward, which pulls the a-arm
> mounting points (namely the forward
> ones). The stress the body exerts on the engine to make it
> accelerate forward along with the car is
> easily handled by the engine mounts.
>     The stress on our lower rad supports is due to the torque of
> the engine, which translates to
> vertical motion at the center of the beam. The cause of the heavy
> cracks on the bottom of our beams
> is downshifting followed by rapid clutch release. I really cant
> see how that stayrod would help in
> that at all.

The way I see it:

The engine pivots on the tranny side mount & the engine side mount.  Draw a
line that goes through the center of both mounts (the canter of the rubber
part) & you will wind up with the axis everything pivots on.  This line will
be slightly above the top of the transmission & run kind of diagonally
through the engine compartment.

Now to stop this rotational motion, you will want the mounts in a radial
direction as far from this axis as you can get them.  This is Why VW has one
at the very front & one at the bottom of the tranny.  By mounting this stay
rod to the top of the tranny it is very close to the rotational axis &
therefore has very little mechanical advantage.

I have thought of making a similar 5th mount, but I had been thinking of
running it from the end of the cylinder head to the fire wall.  This way I
would be locating the mount as far from the rotational axis as possible,
giving it maximum mechanical advantage.

Now, the problem I cam up with next is the top of the fire wall would not
have much strength, but since I was going from the top of the engine any
ways, I figured a good way to kill 2 birds with one stone would be to tie it
into an upper stress bar.  What I had bee thinking was to make a sort of 3
point stress bar that ties both towers together & also has some kind of tie
to the fire wall.  Once this is done it would be quite simple to make some
kind of arm that could then be solidly bolted to the head, giving the engine
3 mounts with which to distribute the rotational forces through.

These are just some thoughts that I have had, I haven't actually made
anything yet.  I do agree that any of the above options will greatly
increase noise & vibration entering the cabin, but I was planning on solid
mounts anyways, so what's a little more noise by that point?

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Philip P. Mueller III
Westbrook, CT - USA
mailto:philipm3@tiac.net
http://www.p3racing.net
 
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