At 07:52 AM 8/20/2003 -0500, you wrote:

 
3 inch tach!!! John, I think what you really need is some glasses :-)
 
For the record, since the tiny tach expects one pulses per revolution, you'd have to divide by 12 to get the proper reading if you hooked it up to the tach output.  I don't think that would be the best way to hook a tiny tach up though. 
 
Most normal tachs come with a switch, or some other method of setting the number of cylinders, and the choice is usually 4,6, or 8.  Since 4 cycle engines fire half of their cylinders on every rotation, the tach expects to see half the number of cylinders pre rev.  If you use the tach output of the EC-2 for a normal, off the shelf tach, you'll have to divide as follows:
 
4 cylinder setting, 2 pulses per rev, divide by 6
6 cylinder setting, 3 pulses per rev, divide by 4
8 cylinder setting, 4 pulses per rev, divide by 3
 
Now that I think about it, what the heck does that Geo 3 cylinder engine do :-)
 
Rusty (it's too early)
 
 
 

So, if the 3-rotor fires every 120 degrees of crank rotation, can I just take an off-the-shelf unit and set it to 6 cylinder mode and be good to go?  Sounds too easy! 

Mark Steitle