I would think that using sound or vibration would be a lot less accurate. Sounds don't always have a definite moment where they begin. Your measurement could slide around quite a bit. Ignition pulses I think would be a lot more defined.
-Joe Merlino
Boston, MA USA
1982 BMW R100 (decomissioned), 2003 America
Triumph: Cool enough for The Fonz, cool enough for me.
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