If you refer to archive message# 49009 on Nov 8, traces of coil control and CAS signals are there.  I have 2 EC2's driving LS1 coils and all 4 controllers show the same behavior.  This affects spark intensity and timing only below about 1200 RPM and is only a factor on start up or very low idle.  Above the transition at about 1200 PM, dwell time are consistently in the range of 4 to 5 ms regardless of the mode 8 setting or RPM.

Steve Boese


________________________________________
From: Rotary motors in aircraft [flyrotary@lancaironline.net] On Behalf Of Tracy Crook [tracy@rotaryaviation.com]
Sent: Thursday, November 26, 2009 8:25 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Ground isn't ground

I haven't noticed the spark being that weak during cranking but haven't made any specific measurements of it either. The spark will be weaker due to the voltage drop of the battery if nothing else, even if there is no drop in the wiring.

Dwell on the EC2/3 during cranking (below 400 rpm) depends on the version/engine type but on the 20B it should be well beyond the minimum saturation time of the coils.   My concerns have been that it is too long during cranking rather than too short.  Dwell time longer than required for coil saturation adds nothing to spark strength but does heat up the electronics in the igniter.

IIRC, Steve is using the RX-7 type igniters which is a different situation.  They control their own dwell internally (after the first cycle) and the EC2 only controls ignition time with the negative edge of the control pulse.

Tracy



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