Winterburn Ignition

[MikeD]

Does anyone have any experience with this? Seems to combine aspects of both CD and inductive...

http://www.capacitordischargeignition.com/

[Circlotron]

I didn't read the entire patent #3564581 yet but the diagram in it is fundamentally no different to any CDI I have worked on in the last forty years. If you are looking for a system that combines CDI and inductive, ICE has one that piggy backs onto an existing CDI. Uses an additional coil that combines its inductive output with the CDI coil using an MSD automatic coil selector. (Two sets of high voltage diodes)

[MikeD]

What about the claim about increased spark duration?? After much reading it seems this ignition was the basis for the Delta Mk10.

[Circlotron]

The business end has some similarities with the Delta 10 and older (non digital) MSD7s. The capacitor dumps into the coil primary and once the cap voltage hits zero the coil continues to pump up the capacitor in the reverse direction. Think pendulum swinging from a height to the lowest point then continuing on upward again by to not as high as before. The reverse charged cap will now discharge into the coil a second time but with only about 1/2 the voltage and 1/4 the energy as before. This second dump will extend the total spark duration a little but it's not a lot to get excited about.

The dump capacitor, SCR and coil primary is like a piston, connecting rod and crankshaft - there is only so much you can do with three parts. The thing is not so terribly different from many others.

[modok]

Yeah If you use a fairly large Capacitor and a big olde fashoned coil it will have "long duration" from the swings.

I don't think anybody ever proved letting it swing is actually better, but it isn't really worse either, a lot of it has to do with the coil. Transformer coil will give you a shorter stronger spark with pretty much no swings so you can swap and see for yourself.
I built a mark 10 box with the capacitor on the outside so i could change it. I messed with that and different coils.
Larger cap didn't work worse, not sure if it was better, but I can say it is true the power supply had a hard time keeping up as RPMS rose.
It's quite -plausible- the use of a smaller value cap, and MSD's choice of not letting it swing reverse, were both for the sake of making the most of the power supply.

His claim that a larger value capacitor charged to a lower voltage works well with many older "stock ingition parts", that would be crosfiring with an MSD, might be true. Seems reasonable. My fooling with it I decided I liked inductive ignition better, but if I had gone the other way I probably would have bought one of his boxes, and I still may, just for the sake of it.
Always a fan of a no baloney solid engineered unit, and it does appear to be so.

[Fred Winterburn]

CD Ignition and its Superiority in Overcoming Shunt Resistances.This might be of interest to some of you folks. Might not be an easy read but it is explained as simply as I know how without going into great detail. This dispels the myth that it is a fast voltage rate of rise that makes CDI superior to inductive ignitions in overcoming a shunt resistance. I've had a couple of electrical engineering reviews, and they are in agreement with what I have found. Fred [attachment=0]CD Ignition and its Superiority in Overcoming Shunt Resistances.pdf

[Geoff2]

What do you guys think about Pertronix's claim that their small Pert III module multi sparks throughout the entire rpm range. I would think this would require CD ign, which usually have a bulky transformer.

[modok]

What do you guys think about Pertronix

I think they ought to fall in a hole.

[Circlotron]

If some ignition needs to multi-spark to get enough duration that almost certainly means that it spends some time between sparks charging up to get ready for the next spark. That means there is nothing happening between sparks. MSD6 for example arcs only 12% of the time for it's 20 deg "duration" of sparks despite advertised claims in the black trace as per the left side of the pic. 88% of that time it is doing nothing to light the fuel. Even at 6000rpm the single spark at that speed is only 6 deg duration. One long uninterrupted spark should have a much better chance.

[Fred Winterburn]

I haven't tested a Pertronix 3, but haven't read much good about them (misfiring and timing issues mostly). They won't work for triggering my CDI so I never bothered to buy one for testing. It is still an inductive ignition so if it is multi-sparking the lull between sparks is likely far too long given the time required to flux the coil between sparks, even if each spark is purposely truncated (glow stage chopped off) to give more dwell time. In my opinion the interval between sparks should be no longer than 200 µS. The old MSD 6 had a full 1 millisecond and that is far too long to wait. That's why the MSD makes a squeaky sound. Fred

What do you guys think about Pertronix's claim that their small Pert III module multi sparks throughout the entire rpm range. I would think this would require CD ign, which usually have a bulky transformer.