Dyna ignition booster

[Burkey]

What can you guys tell me about it. I was thinking of one to add to my points. I was told sparkvoltage rise time 50% faster for more efficient combustion. has some one tried this Dyna booster out is it good or bad.

[kell]

I can make a unit that you can install at the coil, which is how I have been making them. But like I mentioned in the classifieds posting you can also install it underneath the breaker plate -- assuming you have a separate breaker, not a cone-side engine -- this is the better choice; the circuit will have protection from the weather and be hidden. Send me a message letting me know which kind of installation you will do and your address so I can send you one with full instructions.

[2dogs]

kell: I have converted this '63 basket case to 12V running a 1965 auto advance circuit breaker and a 4.2ohm Thunderbolt coil from CCI. I've started the engine but not ridden it as it still needs wheels and more work.

Would your spark amplifier be appropriate here if I stay with the points type breaker? Did I read that you are also building and selling solid state breakers?

moses@frontier.net

[kell]

If you want to stay with points but add a "spark amplifier," my circuit should fit the bill. I've just got a couple of things to say about it.
* The circuit, while it saves the points, won't really do anything to boost performance unless you change to a three ohm coil.
* I was offering two options: installing it at the coil or installing inside the breaker; however, during recent testing some transistors in the breaker installation have failed, probably because of engine heat. So I'm dropping the in-breaker installation option.

As for your question about building breakers,
I don't build new breakers but I have developed a mod for the manual advance breaker that replaces the points with magnetic sensing: a true electronic ignition. I haven't done this mod on an auto-advance breaker because I haven't got my hands on one yet.

[2dogs]

kell: "It's a switched transistor that runs the coil. The points are only there to tell the transistor when to turn on and off, and the transistor deals with the heavy current and voltage from the coil."

This statement of yours, quoted from the Forum 2 board, is the part that sounded good to me. And we've already exchanged a couple of emails to establish that you've agreed to build one for me so everything is good.
Perhaps later I'll change from my 4.2 ohm coil to a 3 ohm coil and see about that performance increase. Why does that help, anyway?

[kell]

The resistance of the coil determines how much current goes through it during dwell. Current = voltage divided by resistance. In round figures, compare:

12 volts divided by 4 ohms = 3 amps
12 volts divided by 3 ohms = 4 amps

The energy stored in a coil is proportional to the square of the current. So the energy in the two coils compares as 4 squared versus 3 squared. 16 divided by 9 is about 1.78. Which means that a three ohm coil has about 78% more energy stored in it when it finally comes time to deliver the spark, if the two coils have the same inductance. If you find out the inductance of each coil you could calculate the energy comparison exactly. (The formula for energy stored in a coil is current squared times inductance divided by two.)
Sounds good, but whether it's worth spending the money on a new coil is up to you. I would say if your present coil performs satisfactory, use it. I didn't like the way my bike ran with the old 5 ohm coil and I had another coil on hand so I switched. Actually a 1.2 ohm coil and a ballast resistor of about 1.4 ohms. 2.6 ohms primary resistance is a little low for the spark improver, as the power transistor I use now in my kit gets a little hot on its wimpy heat sink that has just a couple square inches surface area. How much current a particular setup can handle depends on the power transistor it uses, the surface area of the heatsink, how much air flows around the heat sink and how close it is to heat sources. This is why I ditched the idea of installing transistors in the breaker; the metal of the breaker gets real hot sometimes.

[2dogs]

kell: Ok, Ohm's law at work on the current product. I should have guessed that from 25 years as an amateur radio op but didn't even give it a thought.

Since I can't think of a way to calculate the actual inductance or use a chart without disassembling (destroying) this new Thunderbolt coil to measure the wire size, length, radius and number of turns I will probably never know the actual inductance. Now if I had one of the old grid-dip oscillators...but do I need to know this info that much? No.

Very interesting answer you provided...thanks for the brief refresher on basic electronics! I may look for a way to mount your device with some additional heat sinking to help it run cooler, it possible, and later a used but working 3 ohm coil.

With Respects,

2mutts