MULTIPLYING REACTOR
At idle, the stator locks on its one-way clutch,
stops turning, and redirects the flow of fluid
exiting the center of the turbine. On throttle
application the fluid exiting the center of the
turbine hits the blades of the stationary stator.
The reason this is key is that as the fluid jets
out of the center of the turbine the vortex is
turning the wrong way – against engine
rotation. The stator – or reactor corrects
the flow direction of the fluid and multiplies
the energy contained within. This helps the impeller
to spin the turbine faster by redirecting the
fluid from the center of the turbine. The fluid
then enters the center of the impeller with engine
rotation, and then back out through the outside
blades at a higher flow rate. In this way the
stator allows the converter to multiply torque
as the turbine assembly spins up on its way to
the coupling phase of 9/10ths. The one-way clutch
in the stator will release as the 9/10ths is
achieved and the stator will freewheel, and go
with the flow. The angles and curvature of the
stator blades have great influence on how this
multiplication of torque is delivered – or
whether the converter delivers a soft or hard "hit" or
torque. The reactor, therefore, can greatly influence
reaction time. Altering power delivery to the
chassis and tires can make the difference between
hooking up, and going up in smoke.
SIZE DOES MATTER
While the stator controls the multiplication
and delivery of torque as the torque converter
reaches the desired 9/10ths, other factors control
when the converter will stall, or start on its
way to 9/10ths. Stall is the condition where
the impeller is spinning around with engine rotation,
but the turbine is stationary – such as
at idle. Maximum stall is the point where this
situation is overcome and the turbine starts
to spin. Factors that control stall are the physical
size of the converter itself, the angle of the
blades within the impeller and turbine, vehicle
weight, and the horsepower and torque created
by the engine. Knowing the various factors that
affect the fluid dynamics inside the converter
an important conclusion can be reached. Converter
selection depends not only on converter construction
and size, but also largely on the vehicle it's
going into. A converter that's right for one
vehicle or combination may be entirely wrong
for the other. From tire size to chassis setup
all factors must be taken into consideration
in making the best possible choice. There is
no one-size-fits-all racing converter. |