Keep in mind you can NOT see a magnetic field with the naked eye,
Science deniers won't understand this because they can't see it in operation,
But study the electro-magnetic link...
EVERY electrical current produces a magnetic field.
That magnetic field spins around the wire (conductor).
That magnetic field is lost energy as it's spun off into space.
(And creates Electro Magnetic 'Noise', all energy goes somewhere, not necessarily where you want it to go)
Using a spiral wound wire (see the pictures of spiral wound wire cores in OP's picture) spins some of its magnetic field back into the wire next to it in the spiral, so it preserves more of your spark energy without creating so much EM noise.
It's not a 'Super Conductor', but it's also not a million dollars an inch or has to be super cooled...
Now, the other half of the electro-magnetic link is,
When you pass a magnetic field through an electrical conductor, it creates ('Induces', Induction) an electrical current.
This is the way your generator/alternator/ignition coil works (and every transformer).
The 12 volts from the battery passes through the PRIMARY winding in the ignition transformer (coil) and builds a magnetic field...
When that circuit is opened, the magnetic field collapses onto the ferrous iron core, passing through the SECONDARY (high voltage) coil/winding...
The magnetic field moves, passes through the copper winding, and that INDUCES the high voltage discharge.
You only make high voltage for the milliseconds it takes the magnetic field to collapse, so TIME is very
Limited .
You can drive the voltage up with a wide plug gap, which robs you of Amperage & Duration (time),
This results in a weak, 'Thready'/thin, short duration spark,
Or you can close up the plug gap some, and put some of the spark energy into amperage, making the plasma spark kernel much hotter in temperature.
When you see the difference visually, it's the difference between a 'White' thread in the gap that makes a quick 'Snap', sometimes the spark is so weak & fast you can't actually see the spark, just hear it...
And a blue spark kernel that makes more of a protracted, sizzling 'Pop'.
This is of course a line voltage ignition, usually around 12 volts, with a single discharge...
We aren't talking a CDI that will charge the coil with 600 volts, and recover fast enough to fire the plug 5 or 6 times.
CDI units give you an automatic 500-600% increase in spark energy applied to the fuel/air mixture simply because it is fast enough to fire the plug 5-6 times (at lower RPM, usually under 2,500 rpm).
Since most of us crawl at under 2,500 rpm, a CDI unit is particularly useful, getting the cylinder fired under load at low RPM which is difficult....
Capacitive Discharge Ignition (modules) are an entirely different animal from line voltage/single fire ignitions,
While VERY useful, not entirely necessary if you get your 12 volt ignition firing correctly.
One good thing about 12 volt ignitions, they have been used by every manufacturer since 1975, and a ton of the different components work together, so you are never really 'Stuck' once you learn how to mix & match parts.
Any salvage yard or parts store will have something that will get you on the road...
I have two (dual) ignitions, and the secondary/backup will always be off the shel, common parts for this very reason....
In fact, if you have read my write ups, you know I go with direct replacement parts, things that swap directly on.
Some minor connectors might need to be changed, but a few twisted wires will get you out of a 'Stuck/broke' and back on the trail...
Every junk yard is full of Ford caps, rotors, coils, modules, same with GM stuff, and in a pinch I'll go with Chrysler,
Just what ever fits the application best...
Every parts store carries the aluminum terminal stuff if you need it, and it will get you home, if not 'Optimum'.
I don't need a 20,000 RPM roller bearing distributor in a 4,500 RPM Jeep,
What I need is something that is efficient, easy to work on, and lives a LONG time so it doesn't cause problems.
And we are back to... APPLICATION...
