Well I read that one, and the one by Hoople. Both were very interesting. I get the jest that biased dc voltage across the ionization is measured and sent back to the ECM for it to compare to calibration tables. As to it being measured "after" detonation I can only wonder, if that means after the ECM (or ignition module or pickup coil trigger) has told the coil (by cutting it's primary field causing collapse) to fire the plug OR it measures ionization during a period prior to firing the plug so as to actually tell if it's pre-ignition or ignition. That part escapes me as to how it can decipher pre-ignition ionization as opposed to ignition ionization. Albeit the term "after detonation" seems to imply the former. I understand I am told that ionization is affected by pre-ignition, I can only take it by faith that the effect is still showing up after plug firing, i.e. possibly more ionization registering than if no pre-ignition had occurred (?). That's getting a lot from those pre determined calibration tables.
I emailed the plug manufactures and only 2 have replied thus far. It appears that pretty much "ALL" ECM/PCM engines now days must have "some" resistance built into the plug and/or wires or the interference will affect the ECM and cause poor idle and erratic running. Most of them say the resistance is about 1K ohms. I would guessitmate the voltage coming off the collapsing coil at trigger is somewhere around 120,000 volts, but that last figure is purely my own guess based on 12 volts times 1 to 10,000 primary to secondary ratio.
I still don't really see how a spark plug could make all that much difference in the resultant voltage spike. Nor have they been proven to increase or decrease performance to any real degree. If some are saying it does, then far be from me to say they are wrong, I'm only saying I ain't convinced yet. However from what I have read I am pretty much convinced that other factors (that have been proven to affect performance more than plugs or wires) such as stage one AC, more air flow exhaust pipes and higher compression setups.
So then it would appear that everyone that has a stage one (or stage 2) setup that does not have a "corrected" ion calibration table in the ECM is definitely not utilizing the ion data. Even if you have a tuner (regardless of it's sophistication) if it's pre-determined calibration tables have not been compenstated then (from what I've read) the ion data returned is useless.
If I might say so, (which is a bit presumptious for an old redneck like me) I find it somewhat incredulous that such a system would be designed to base it's reactions on a pre-determined calibrations given the many tempature and atmospheric conditions that any given engine can be exposed to depending on it's location of operation environment. Notwithstanding that a large percentage of us have nulled that effect with many more items than spark plugs.
I thank you for the information though, it was good reading.