ignition timing?
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From: Montreal, Canada
ignition timing?
I'm just trying to understand what ignition timing does. Could anybody enlighten me as to what happens to the motor when you advance or retard ignition timing and how does one know when they have perfect ignition timing? Thanks in advance.
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Joined: Mar 2007
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From: Woodstock, Ont , Can
If the fuel is lit up too late as in retarded, all the fuels capability is not used with some of the charge going out the pipe. It will be loud and gutless.
Timing advances with rpm to a point, because something called lag comes into the picture. Piston speed increases but fuel burn rate is somewhat constant so the fuel needs to be lit up sooner since the timeframe it has to do work is less. High loads need the advanced reduced because the fuel charge is higher and if you light that big volume up too soon it will detonate. Once the load is back to normal timing can be advanced again for correct burn. I'm sure plenty will chime in on more aspects, but that's pretty much the basics. The word timing itself somewhat explains it. Where it needs to be depends on compression ratio, fuel grade , temp, atmospheric pressures, and load. In most cases perfect timing is just on the verge of detonation, and not always practical, but 99% of modern autos run there.
Ron
Last edited by rbabos; Apr 8, 2009 at 04:17 PM.
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