Base Spark Advance vs Spark Advance

[BlackBird_SR71]

What is the difference between Base Spark Advance and Spark Advance? Attached is a screenshot of a datalog, and you can see a difference of 1.2 degrees between the two. Which one should be used to show real time Spark advance. Is Base Spark Advance before any corrections are made? Engine temp is a bit high on this car ( 201 F ) and it may be pulling some timing.

Note in Graph #2 at the cursor line, the traces are identical, but the values on the right hand side vary. At cursor line of 83.078 seconds , Base Spark Advance is showing 38.1 degrees, but Spark Advance shows 36.9 degrees. Trace lines look identical through log, but values differe. Why is that?

Attached are a screenshot of the above time period in the Datalog. Edit: Datalog is too big to upload directly. Exceeds 1mb. Zipped datalog in Reply below.

Spark and Base SparkScreenShot002.jpg

[BlackBird_SR71]

Had to Zip Datalog as it was too big to post directly.

Jeff Datalog of surging 2017-07-01_15.02.41.zip

[jsmcortina]

Base spark advance is from the tables. Spark Advance is the final figure after any modifiers.

Take a look at the Spark Calculations Summary page in TS.

James

[BlackBird_SR71]

Thanks James.