Finally got around to putting a spreadsheet together to do the charge time calculations, translating the more widely used milliseconds into the degrees of crank rotation that the PFC/Datalogit uses. Spreadsheet is pretty self explanatory. Enter the desired charge time in mS in the yellow cells and the corresponding degrees of crank rotation is computed in the orange cells. Duty cycle is computed in the red cells and total cycle time (one 360* revolution of the crank) is given in mS. You can download the spreadsheet from the link below. It is saved in open format so it should work on multiple applications.

http://www.lms-efi.com/stuff/charge_...alculator2.xls

 

Just reformatted the spreadsheet to show duty cycle for leading an trailing. Forgot that the PFC is firing the leading in wastespark.

 

I've played around with this table a little bit before, but I never noticed much of an effect when making smaller changes.

 

Are you running the Twin-Power? With a CDI there won't be anything in altering charge time. If you're using stock coils, or some other form of inductive coil, there can be a great deal of gains and losses in proper charge time programming. At the least, you can easily see what the numbers mean now in a more widely used and understood format.

I made some more changes. Added separate calculations for leading and trailing. Link above has been updated.

 

Using an oscilloscope to measure both leading and trailing peak output voltages when adjusting the Settings 4 dwells should be more an accurate way to tuning the ignition system for peak performance.

 

True. But if you know the characteristics of the coils you're using that's not absolutely necessary.

 

Testing beats out theory every time!