That's great data to have Rusty, thanks for the contribution.
 
Now I just need to figure out a way to make it useful.
 
Dave Leonard

    -----Original 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)