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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 operation.
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

Phone (760) 947-5240 Fax (760) 948-0196

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