MoTeC Global Forum

The basic setup for ignition coils that comes with the software is battery compensation, (battery voltage vs dwell times). I was wondering if there was a way to control the coil dwell with respect to voltage, load and duty cycle ?

We normally use voltage as the axis for the dwell table but you can configure this as a 3D table and assign any of the ECU channels as the axis. Load point could be used butr what duty cycle were you wanting to use?

I am just making sure the poster realizes that the "A" key calls up the axis configuration. That one took me a bit to find.

Electron Speed: Sadly I was not aware of A key function. Thank You

A post on EFI 101 prompted me to pose this question (mostly because I did not fully understand the response in the post). I'd appreciate any insight as to what was being suggested and more importantly how to implement it using the M800. The post is http://efi101.com/forum/viewtopic.php?t=3558&start=20 and specifically is:

We were in EMS row at the PRI Show, one booth from Motec.
I asked the brillant Shane T. how the ADD the correct calibration for coil control.
His method was to use Battery comp. as one of the Axis, the other was
a created AUX channel, the other Axis.
The AUX #8 is now a combination of two objects (RPM AND MAP).
Thus coil charge is based on 3 axis control.
Items are supported to include, Voltage, Load, Duty Cycle.
Quite clever, Shane.

Lance

What is being suggested here is using the result of one table as the axis for another. The Axis setup in M800 allows you to do this. You could set up an Auxiliary Table on an output (even if the output is not connected to anything). In the example described on EFI101 the auxiliary table is used to apply a value (in duty cycle)based on Engine RPM and load with RPM being the X Axis and Load being the Y axis. The result of this table is then used as an axis for the Dwell table. So the Dwell table has an X Axis of Battery Voltage and a Y Axis of Aux8 Out Duty Cycle.

This means that the ECU can calculate Dwell as a function of Battery Voltage, Engine RPM and Engine Load instead of just Battery Voltage and RPM.