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From: Walter Atkinson <walter@advancedpilot.com>
Subject: Re: [LML] Re: One mag, One electronic ignition

1) detonation is not the issue.  The thetaPP is not significantly--if  
at all--advanced during detonation.  The peaks are occurring  
primarily after the peak.

2) A slight advance of the timing will result in a more rapid  
increase in the pressure as the piston is still going up.  This  
speeds up the flame front.

Walter


On Jan 12, 2008, at 1:28 PM, bob mackey wrote:

>    I would be interested to know if there is any theoretical
> explanation for why a 2 degree timing change might cause a 10 degree
> theta-pp change.  That would suggest that flame-front moves faster  
> btdc
> than atdc, by a lot.   It would also suggest that the impact of  
> mixture
> changes on theta-pp is amplified in a similar way.

Detonation. As detonation starts, the pressure should arrive earlier.
That's a hypothesis anyway. Don't know what was measured or whether the
measurements made would distinguish detonation from surprisingly fast
flame front.

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