Ignition Timing Advance Tables - Logic?

[jacobs53]

Hi All,

I have started to "play" with the versatune software more and more over the last couple of months and need some clarification on the logic utilised for the ignition tables.

For CL and OL ignition tables there are:

Base Timing Normal Extended
Base Timing Normal OverLoad
Max Ignition Timing Extended

I know the Extended and Overload tables are exactly the same on the default High Load map, however what is puzzling me is the Max Ignition Timing Extended Table. I am assuming that +ve values mean the ignition timing is advanced as explained in the tech screen?

If the Base Timing tables are modified to request advanced timing (+ve value compared to standard) then unless the Max Ignition Timing Extended table is changed as well to either the same value or slightly higher (again assuming +ve is more advanced) then the value defined in the Base Timing table will never be achieved. If you refer to the low load values in both CL and OL modes the Base Timing values are higher than the Max Ignition Timing tables.

Is my understanding correct?

Thanks
Lee

[Steve @ VersaTune]

The "Max" name is a bit misleading. It appears that the ECU starts at the base timing and moves toward the "Max" timing value. In very low load situations, it will actually decrease timing going from base to max.

[jacobs53]

Hi Steve,

Thanks for the feedback. OK, so the Max table is actually the target for the ECU to achieve starting at the base value, regardless of +ve or -ve values!

Good to know, thanks!

Lee

[mituc]

The timing values used are those from the Base table. The Max table only establishes some limits so that no matter what you command in the Base table those values cannot go above what's in the correspondent cel in the Mac table.
The Max table should not count when the ECU adjust the timing unless the values in the Base tables exceed what's in the Max tables. At first the values from the Base tables are used and then based on various other variables (BAT, ECT, knock values - as can be seen in the Nigh BAT/ECT timing tables) it will decrease (and only decrease) the timing accordingly no matter what we're talking about open loop or closed loop.

[nitroelectric]

@mituc,

Thanks for the post, most informative


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