Mailing List flyrotary@lancaironline.net Message #10097
From: Russell Duffy <13brv3@bellsouth.net>
Subject: RE: [FlyRotary] Re: Turbo and the EC2
Date: Fri, 30 Jul 2004 17:16:18 -0500
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message
It could be that   with faster combustion wave propagation that you would want the timing of the lead and trail closer in timing rather than further or possibly vice versa {:>). 
Ed Anderson
 
Exactly right Ed, or vice versa  :-)
 
Through the miracle of copy and paste, I'll attach the timing split from my old FD engine computer.  Keep in mind that this is NOT the stock Mazda timing, though it's probably close to it.  The top row is the scale in RPM, and the first column is the scale in inches of mercury.   The numbers in the box represent the difference in degrees between when the leading, and trailing ignition will fire.  Positive numbers indicate that the leading fires before the trailing. 
 
It's interesting to note that aside from the idle range, the timing split is 0 until you get to around sea level pressure.  From there, it quickly increases to about a maximum level for the rest of the boost range.  From this, I would assume that increasing the split reduces the chance of detonation.  
 
Still hard to say how important this is for us.  How much greater is the chance of detonation?  How much power would you lose if you had to run on trailing ignition only with the split built in?  
 
Cheers,
Rusty (doing my turbo duties, though I'm not sure why) 
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