Mark Steitle wrote:

This seems like a good time to ask a question that I have had for some time now cooncerning the firing of the leading & trailing plugs.

  Q:  Is it best to fire the leading and trailing plugs separately (trailing plug retarded 10 degrees) or can they be fired together?  What are the pro's and con's of each.  Paul Yaw's web site indicates that the primary reason for the trailing plug is to reduce emissions.  If that's the case, is there some other benefit to firing them separately?  If they can be fired together, a dual tower coil can be used, saving some weight and complexity.  I have my 20b running on a test stand using three dual tower GM coils and it doesn't seem to mind.  In this scenario if the leading plug were to quit firing for some reason, the trailing plug would keep things running with minimal loss of power.  The dual tower coils are also very light, although I haven't weighed them, I guess they're less than 1 lb each.  They retail for about $20/ea.

 
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