Capacitive Discharge Ignition GONE!

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68 CUDA FORMULA S

68 CUDA FORMULA S

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Does anyone know what this does and what it would have been used for? It was in the trunk of my 68 barracuda that at one time in it's life was a 1/4 mile car. Not that I am going to use it but I would like to be able to understand what it did.
Thanks
Bob

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usually a CDI ignition precharges the coil with not 12, but 300V (!) of power by a large capacitor. Allows a much hotter spark, a larger plug gap for a larger kernal, and the ability to do multi strike or electronic delay (retard)

Here is a summary:
Advantages of CDI
  • The major advantage of CDI is that the capacitor can be fully charged in a very short time (typically 1ms). So the CDI is suited to an application where the insufficient dwell time is available.
  • The capacitor discharge ignition system has a short transient response, a fast voltage rise (between 3 to 10 kV/ µs) compared to inductive systems (300 to 500 V/ µs) and shorter spark duration (about 50-80 µs).
  • The fast voltage rising makes CDI systems unaffected to shunt resistance.
Disadvantages of CDI
  • The capacitor discharge ignition system generates huge electromagnetic noise and this is the main reason why CDIs are rarely used by automobile manufacturers.
  • The short spark duration is not good for lighting relatively lean mixtures as used at low power levels. To solve this problem many CDI ignitions release multiple sparks at low engine speeds.
 
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Is that like a Delta Mark Ten? If so... That’s the earliest CR ignition I can think of. They worked very good. Not for high turn ratio coils.

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I know exactly what that is. "back in the day" early 70's there were a number of aftermarket, add-on electronic ignition systems, often triggered by breaker points

The two which stick out in my mind is this one here, and another called Delta Mk 10. Both were similar.

MSD is a CD ignition, but a bit different and more modern, as MSD generates multiple spark discharges (why it's called MSD LOL) at some RPMs

The way a CD works is similar to an electronic camera flash /strobe. A high voltage inverter charges up a capacitor, and when triggered, the cap disharges it's energy into the ignition coil. This causes a tremendous high voltage pulse. There is NO DC current going through the coil as there is with breaker points, or Mopar breakerless, or GM HEI, or similar systems known commonly as "switched." Kettering is a more proper name.

BECAUSE there is no DC through the coil, the core never reaches what is called (magnetic) saturation, and can be more efficient because of.

Also because there is no DC, the coil electrical characteristics can be optimized more for CD operation and deliver higher performance.

CAB (California Air Resources Board) evaluation of the SST towards the bottom:

https://ww3.arb.ca.gov/msprog/aftermkt/devices/eo/d-20-1.pdf
 
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I have a capacitive discharge unit to power electric turnouts on my soon to be model railroad. Rather than rely on low 12V to power the turnouts, the CDI unit zaps them with 25V. This assures they SNAP completely one way or the other. Works really well.
 
Thanks guys. I had never seen one before, we were just poor racing kids back in the day and could not afford this kind of stuff on our racing budget's. Anyone want it? it's just going to get tossed.
Thanks again
Bob
 
I will take it just to have it, will go along with some of the odd ball ignition stuff I have. PM me what you want.
Ray
 
Oops, I didn't know this was a sale thread.
 
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