4L80E line pressure

[pullincrazy88]

does anyone know how high you can set the trans line pressure of the voltage for a 4L80E without burning up the solinoid.

[rtuhro]

A voltage source in not a good way to control this electronic pressure control. It is a force motor that responds to current. The current specification is 0.06 to 0.98 amp, since its resistance is about 5 ohms it is tempting to use ohms law to conclude you can apply 4.9 volts to it and get the maximum current; however this is not a good solution, the variation of the force motor resistance and varying source voltage would make this an unstable control. It is fairly simple to connect a power transistor with a zener diode in its emitter and a voltage control at the base, with the force motor connected to the collector. the transistor would have to be a power device with a good heat sink. You could even derive a signal from a MAP to feed the base and have the pressure vary with manifold pressure. The factory controller accomplishes this current control with a pulse width modulation but this should not be necessary, just more power efficient. I am working on this control just now to allow me to use a 4L80e where there was a TH400 with no control. I will have a tested design in a couple of days.

[joecar]

rtuhro welcome to the forum :cheers: