I’ve noticed both a high lag and an inconsistent lag between requested cylinder cut and actual cylinder cut (at least when going through the Vehicle Speed Limiter). First, my settings are pretty basic, a 1:1 mapping from “Trial Cut” to cylinder cut, with a 50% ramp per revolution:
But here’s a sample of it in action (I’m using cylinder cut for upshifts with a DCT; yes I should use more ignition retard and less cut, but this should work too):
- The first peak seems 30ms delayed, ok not terrible but not great either. Not sure whether it’s relevant but RPM is around 5700, so let’s say 10ms per crank revolution or 20ms per cam revolution. Maybe the delay is related to that? Can we get cut updated more than once per cam revolution?
- The second peak is less consistent. The rise is delayed about 8ms but the decay is delayed about 30ms. Is this related to where in the cam rotation it is?
- If I utilize ignition timing instead, will it react more quickly / more consistently?
Maybe I can hone in on this if I up the logging frequency of Trigger/Primary tooth cycle.