Specifically, How does a D/C CDI box work?

Fuel Supply & Ignition Systems
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theKbStockpiler
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Joined: Sun Jul 15, 2012 10:25 am

Specifically, How does a D/C CDI box work?

Post by theKbStockpiler »

Hello fellow enthusiast.
This is a topic that is close to non existent on the internet. I found this video on A/C CDI's but it does not really go into much detail. I'm interested in both A/C and D/C but will be working with a D/C. https://www.youtube.com/watch?v=0yK3Opq_i0M

Only info I could find on D/C's is that it has a step up coil before the capacitor.
The only info I can really find on either is that they 'discharge' faster than an inductive system.

So here is my logic on the A/C system.
Stator is going to have a peak voltage that the capacitor is capable of charging up to eventually. It's rectified and isolated from the other polarity swing with a diode. Capacitor eventually fully charges up to peak stator voltage but with a higher amp capacity. Spark would not be needed until multiple cycles of the stator so the stator would have to be moving much faster than the tdc of the piston. I'm thinking engergy storage is the main princlple here.
Any insight is appreiated!
Super beetle with attitude
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Piledriver
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Re: Specifically, How does a D/C CDI box work?

Post by Piledriver »

CD ignitions were great in the 70s and 80s.
It was a good idea at the time.

Modern high performance coils like the Mercury outboard ones (IGN1/1A)or even a good VW 4 post have far more energy available to put into the spark, and a much longer spark at that.(duration).
Even run of the mill LS2 truck coils curb stomp a CD ignition energy output wise.

I recall one video of the Boba turbo/AWD with what looked just like the stock VW 4 tower (logic coil w/built in driver) firing that ~1600HP 2L.

Its easy to overthink things. Best move: Ditch the distributor, at least for spark distribution. It is the biggest problem they made go away on any modern vehicle, huge reliability win.

A 72 tooth steel rc truck spur gear fits in a VW 009 or equivalent distributor...
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
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