Capacitor discharge ignition

[shed_dweller]

I have built a very basic capacitor discharge ignition that actually runs my motocycle.

I am wondering about matching the ignition coil to the discharge capacitor. I can not find any info or rule of thumb to follow. looking at commerial units there does not seem to be any rule regarding the voltagle/cap size/ coil resistance or reactance in mili henries.

Any clever chaps able to give me a few pointers so i can work out if I'm getting the most power transfer possible?

 

[crutschow]

A capacitive discharge unit uses the coil as a transformer so coil resistance and reactance are not critical. The turns ratio is selected to give the desired output voltage for the charged capacitor voltage (a typical coil has about a 100:1 ratio). See **broken link removed** or Google "Capacitive Discharge Ignition" for more info.