So you all know that MSD has there Selectable rpm pills for use with there shiftlights and stuff..
Basically the pills are just a two prong pill that has a certain resistor in it to activate msd shift light..
so my question is does anyone know how those rpm pills work..

ie: if i hook the pill up to my tach wire and say the pill is set to 6000, once i rev to 6000rpm will voltage pass through the pill or.......????

Thanx

 

It knows whatever RPM your at. If you have 6k pill, then the light will trip at 6k. The tach wire's voltage will change depending on RPM. Not really sure what your asking? You seem to understand how is works.

 

The pills alone won't do anything for you. They are but one part of a system, which needs a controller base to plug the pills into. The pills are the "coils" of an electronic relay, while the controller is the "base" that you connect control wires to. The relay contacts (N/O & N/C) in the controller bases are what actually switch the control signal passing through. The pills just tell the controller when to switch the contacts.

 

[QUOTE=snakeeater,Feb 23 2009, 12:07 PM] The pills alone won't do anything for you.