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Old 07-09-2016, 07:40 PM
olddog olddog is offline
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Join Date: May 2006
Location: St. Louisville, Oh
Cobra Make, Engine: A&C 67 427 cobra SB
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I decided to graph the same data with Advance on the Y axes and % Load on the X axes. There is a line (series) for 750 rpm, 1000 rpm, etc. You will notice that for 4000, 5000, and 6000 rpm the advance curve is identical, so the three lines are on top of each other and look like only one line. Also 90% load is pretty much WOT on a normally aspirated engine, but I left the boosted engine data as I find it interesting.

In my opinion this shows what the vacuum advance would do to the timing, as you opened the throttle. The previous graph in the previous post shows what the mechanical advance would do as the rpms increase. However with an EFI computer you have a different mechanical at every load and a different vacuum advance at every rpm.

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