The design of the bushing is such
that every axis the suspension sees meets with the Del-A-Lum
material. This means that as the suspension moves through
its travel, there is never any metal-to-metal contact, no rubber or urethane
deflection and zero stiction. In the end, this means that the shock absorber
becomes the only controlling factor in the suspension system, and that's definitely
good.
Aside from expensive custom machining and
equally expensive spherical bearings, there is definitely
one other excellent option, and it might not be near as labor
intensive or as costly as my backyard engineered bearing
system. Better still, it's readily available for
countless
applications (early and late, GM, Ford and others) and as
a result, there's no need for one-off fabrication. What
I'm referring to is the "Del-A-Lum" bushing manufactured
by Global West Suspension Components. Global West is
one of the few "turn and burn" street suspension
companies I've personally run across which truly understand
that shock absorber control is the key. In order to
make the suspension work as designed, you have to eliminate
the compliance or deflection from the bushings and make them
as loose (in terms of stiction) as possible. In turn,
the shock then controls virtually all of the suspension movement. If
you don't like the way the car works, then you adjust the
shock, since it's the only real variable. At least
to me, that seems quite logical.
If you take a close look inside
the aluminum bushing housing, you can see that it is
radially machined, which allows grease to travel the
full distance of the assembly. In addition, the
Del-A-Lum insert is designed with radially drilled
holes along with a groove in the center. Again,
the purpose is to allow grease to pass along all moving
points. |
The key in the Global West system is the way the front control
arm bushings are made. Del-A-Lum is an advanced, extremely
dense, extremely hard plastic material (I'm using "plastic" for
lack of a better word, because that's what it resembles --
in truth, Del-A-Lum is a proprietary material). Basically,
the material does not have cold flow tendencies, and as a
result, it has the capability to maintain alignment over
time. In construction, the bushings are multi-piece
affairs. For example, the first generation Camaro bushings
shown in the accompanying photos consist of an aluminum bushing
housing. Inside is a Del-A-Lum insert. On either
end of the bushing housing, a large diameter Del-A-Lum washer
is installed, sandwiched with another large diameter steel
washer. This provides what Global West calls "six
way surface isolation". In other words, every
direction the bushing is stressed (up, down, forward, rearward,
to the left and to the right), the forces see the Del-A-Lum
material. Because of this, there is zero
bushing deflection, no matter what axis the forces represent. When
you take a close look at the photos, you'll see that the
extra thrust washers are designed to control fore and aft
movement without binding up the suspension. Additionally,
(and perhaps most important for a drag race application),
there is absolutely no suspension bind or galling of the
bushing material. Because of these properties, the
vehicle alignment is always maintained, even under hard acceleration,
braking and cornering (which of course, has little consequence
in a drag car). What these properties mean is the suspension
travels freely, all of the time.
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