Mailing List flyrotary@lancaironline.net Message #11913
From: Al Gietzen <ALVentures@cox.net>
Subject: RE: [FlyRotary] Re: MAP pulses (20B)
Date: Mon, 4 Oct 2004 07:45:49 -0700
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message

Subject: [FlyRotary] Re: MAP pulses (20B)

 

I set the EC2 to mode 7, ran the engine up to 15.5” MAP based on the gauge, and pressed the set button; to try to be sure the stage point was properly set.  Didn’t seem to make any difference.

It still bothers me that you see a change in the engine when turning off the secondaries below the staging point.

 

With the staging point set above 15”; and having both sets of injectors operating at manifold pressures of 10-12”, it seems quite clear that the “staging” is not working. The $64 question is “Why not?”  With the engine running at this MAP setting, I put the voltmeter on the staging relay, and it is not energized; and it should be.  I know the relay is working because with the engine off and EC2 on, it is energized.

 

I'm not surprised that the secondaries (MSD 525) are running smoother than the primaries (Mazda 550) at low power.  One of the problems with larger injectors is that you can't cut the pulse width down enough to limit the fuel for idle settings.  Also, when running minimal pulse widths, the reaction time of the injector becomes a factor.  If there's any variation in the opening and closing time of the injector (partly sticking, worn out, etc), this will cause big problems at idle, and lesser problems as you increase the power setting.

 

I understand what you are saying, but it would suggest that the engines would also not idle in a car; and that Dave Leanard’s engine couldn’t idle smoothly at 900, as he says it does.

 

Checked the staging relay and secondary power circuit is “on” when everything is off (relay not energized).  With engine off, EC2 on, relay is energized and secondary power is off (not sure this is normal).  However; with engine running and MAP below stage point, relay is not energized, and secondary power is “on” (not normal).  Relay coil connects to +12 and to pin 35, which I understand closes to ground when MAP is below staging point.

What "staging relay" are you referring to?

The relay that is utilized by the EC2 to disable the secondary injectors at MAP below the stage point.

Good luck cleaning up your trees.  Maybe that’s what I should; get out my chainsaw and go cut a tree – actually accomplish something.

Al

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