|What It Does
|An explination of what our TV
Made EZ© System does
What should the Throttle Valve (T.V.) cable physically do?
The Throttle Valve cable is connected to the carburetor linkage (or fuel
injection) at one end and to the transmission at the other end. The cable
attaches to a small wire link which in turn attaches to a swinging lever
that moves a dual hydraulic control Valve assembly. The cable assemblies
function is to properly move this combination valve assembly in the transmissions
Valve body, through a full spectrum of movement as shown in pictures #2
and #3. The Valve assembly being moved is shown in picture #1. Starting
at the right, the part throttle/detent valve (visible with the pan off)
is moved back and forth inside the aluminum sleeve directly to it's left.
The part throttle/detent valve pushes on the coil spring which in turn pushes
the Throttle Valve. The springs shown to the left of the Throttle Valve
are to assist in returning the combination to its proper starting position.
The only components that can be seen with the transmission pan removed are
the part throttle/detent valve and a small portion of the aluminum bushing
that it move inside. A small "window" in the valve body casting
allows you to see part of the coil spring but the throttle valve itself
and the return assisting springs are not visible.
The following quote it taken
directly from a General Motors Technicians manual:
- Throttle Valve: Regulates
TV feed pressure from the TV limit valve into TV fluid pressure in relation
to throttle Opening. The throttle valve is controlled by TV plunger
movement and TV spring force. The throttle valve directs fluid to the
MTV up, and MTV down, and line bias valves to control the timing and
feel of the various shifts in the transmission.
- Throttle Valve (TV) boost
valve: Acted on by the modulated throttle valve (MTV) fluid, the TV
boost valve moves against the reverse boost valve and pressure regulator
spring force to increase to increase line pressure as TV fluid pressure
is increased. This prevents the band and clutches from slipping when
engine torque increases.
- Throttle Valve Plunger (
also known as the part throttle/detent valve): The plunger is controlled
by the TV lever and bracket assembly and is mechanically linked to the
throttle body ( Carburetor). Upon acceleration, the plunger moves against
the throttle valve and TV spring to increase TV fluid pressure. It also
controls the opening and closing of the part throttle and detent fluid
ports used to control downshifts and upshifts.
|In laymen terms:
This combination of valves controls the pressure boost of the internal hydraulic
pump which in turn prevents the band and clutches from slipping. It also
controls the upshifting and downshifting sequences and is the major influence
over shift firmness and speed. I don't know about you but that sounds like
what I need to be in control of to have a transmission that will stay together
and operate in a manner that pleases me.
When connected to a carburetor or fuel injections throttle linkage, a correctly
set up Throttle Valve system will pull the cable causing the Part Throttle/Detent
Valve (Picture #1) to immediately start moving with even slight carburetor
linkage movement. The transmission end of this cable is connected to a wire
link, in turn, connected to a rotating lever. This rotating lever pushes
directly on the Part Throttle/Detent valve in the transmissions Valve body.
The correct movement of this Part Throttle/Detent Valve should start (carburetors
at idle, no choke influence) with the rotating lever just making contact
on the Part Throttle/Detent Valve at it's outer most position. (See picture
number # two) When the carburetors linkage (the pulling arm) is rotated
to the W.O.T. position, the rotating lever must completely bury the Part
Throttle/Detent Valve. (See picture # 3) When the part throttle/detent
valve is fully buried, the rotating lever will be touching the aluminum
sleeve that the plunger moves in, acting as a throttle stop. All of the
popular carburetors will not perform this full movement because the carburetors
linkage was never designed for this purpose. While this may not cause
the transmission to fail, it certainly will not be capable of optimum
Designing a pulling arm on your carburetor linkage that pulls the T.V.
cable this fixed distance is the easy part. The challenge really begins
when you desire your transmission to behave in a specific manner. The
physical dynamics of this cable pull can vary radically with different
pulling arm designs. The pulling arm is the radius length from the center
of the throttle shaft to the T.V. cables attachment point.
Another way of
explaining this phenomenon is to understand that the rate of plunger travel
will vary greatly as the pulling arm swings through it's fixed number
of degrees of rotation from idle to W.O.T. A set up that causes the plunger
to travel faster just off idle will act more aggressively then a set up
that causes the plunger to move more slowly just off idle. The rate of
plunger travel speed just off idle will determine the shift timing and
shift feel of your transmission during the normal driving range. Our new
U.S. patent pending TV MADE EZ system allows the installer to vary the
rate of part throttle/detent valve plunger speed just off idle, while
maintaining the correct pull distance with each unique set up. This product
is available only through Bow Tie Overdrives. For more information or
to order, please contact us at
(760) 947-5240 Fax (760) 948-0196
Or, send us