The whole reason for starting this thread was to see if someone had any ideas about the "blip",
I'm fairly new to Compression waveforms too, hence I am showing an interest in this thread. Reasonably up to speed with pressures which I hope will help me, in time, to understand them.
Your Piston Slack / Rock theory , I questioned at first, for the same reasons you did.
I'm thinking that the rocking piston would cause the Seal around the Rings to break momentarily and we would get an attempt at equalisation of pressure between the Combustion Chamber and the Crankcase. Assuming crankcase pressure to be near atmospheric (it is a non runner) so that would cause a rapid drop, not an increase ?
Fact is that at the start of the Blip your Cylinder Pressure is 9.3 bar and rises to 9.6 bar. A Ludicrous scenario, I know, but for a momentary break in the Piston Ring Seal to cause that you would first have to have at least 9.6 bar in the Crankcase ?
It gets from 9.3 bar to 9.6 bar in just 1.1ms & then maintains that increased pressure for a further 1ms - That is no walk in the park !! and an excellent achievement without a bang ?
Common sense & the lack of an alternative makes me think that there must be a gaping hole in my knowledge or I am working with a myth that needs to be burst. Eager to learn from this.
I wonder what the pressure transducer in the dipstick tube, synced to the same cylinder as in the original capture will show?