SpudFiles

Ok, before I go and fry something or shock myself, I want to know if anyone with more electrical experience has tried this before, or if it will work at all.

What I was thinking is if you could wire a stungun in series with an ignition coil, you could probably create enough HV to arc from one end of the chamber to the other, provided everything was insulated properly.

I dont know how much of a preformance boost you would get from a "linear ignition"(meaning, the flame front would propagate outward from an axis, rather than a single point/gap), but having a clear pvc chamber with such an arc in it would be really cool to see.

Wow, that'd be pretty sweet. I'm not sure if it would work though.

Bad news: It will probably arc around the casing of the ignition coil before it bridges the length of your chamber. Electricity takes path of least resistance, so unless you completely insulate the coil, stun gun, wires, and the contacts on the outside of your barrel, it probably won't work.

You might have luck submersing the coil and stun gun in mineral oil, as it does not conduct electricity. I seriously hope you can get it to work because I believe the benefits you stated would provide measurable performance gains.

provided everything was insulated properly.

Yeah, I thought about that. If I try it I know I'll have to incase it in something extremely resistant.
Having a clear case full of electronics immersed in liquid would be anoying(weight), but it would also look cool to the casual observer.

Well conceivably, you could make some sort of watertight flexible polyurethane case to go around the electronics. Not lieka box, but something that fits rather close to them and allows you to fill it with mineral oil or something. You see what I'm saying?

An arc over a foot long would look incredible but voltages that can do that can go through quite a bit of insulation too.

I suspect it will go through the coil insulation on the ignition coil if the voltage increase is actually that high.

I'm not too sure the current from a stungun will be enough either.

I think hotwired is right, the current from the stun gun probably wouldn't be enough and the stun gun would burn out from to much strain being put on it.

Also the insulation would be a major problem, seeing as a spark over a foot long would be roughly 250,000 volts and if you notice, there's like 2 feet of ceramic disks for insulation on major power lines. Maybe If you used 3/4" copper pipe as the conducter and put it in sch 80 1.5" pvc pipe filled with oil, that might provide enough insulation.

Another thing is the ignition coil will burn out because most already are filled with oil and too much electricty through them will boil the oil and let them short out, ruining them.

So, it sounds like it would only work if you make your own coils/flyback circuit, which, I guess, wouldnt be too extremely hard

I dont think It'll take sch80 filled with oil to insulate, as long as its a little more resistant than x amount of air. I cant even get my stungun(says 150kv, probably lower though) to arc through realatively thin amounts of electrical tape

Killjoy: Would there really be enough power going through the coil to boil the oil?(edit: oh yeah I got mad rhymez)
We're only talking about a skimpy stun ciruit and a 9v here.

With so many variables to take into account, it sounds like the only way this will be proven/disproven is if someone actually tries it. I dont have a stungun I want to ruin right now, so some other brave soul with money should try it in thier free time

You'd be suprised, ive seen ignition coils cook with a lot less voltage, but maybe there was something wrong with them, i don't know. anyways it may just be easier to make you own trasnformer and flyback circuit.
(nice rhyming skills by the way.)

And this i has been discussed before, but the advertied voltage on a stungun is very exagerated, usually they don't put out more then 50,000volts. This is mainly for safety but also if you think about it, it would be extemly hard to make something that could produce 150kv in a package that size, and also prvent it from shorting out. and you prbably right, the sch 80 with oil was probably over kill.

I don't think there is much chance of a stun-gun + auto ignition coil working.

High voltage coils are designed for a maximum voltage. In particular, the insulation inside the coil is designed is withstand the max voltage plus a bit extra as a safety factor. If the auto coil was designed for a 12V input and a 20KV (?) output but you put 50KV in expecting to get 1MV out, then you have greatly exceeded the voltage rating of the insulation inside the coil. The coil will spark internally and nothing much will show up on its output terminals. So it seems pretty unlikely that it will work.

I would worry about the coil frying the stun gun. The current draw from the stun gun shouldn't be a problem since the coil probably has more resistance than does the spark gap once a spark actually jumps. But, the ignition coil is going to give a pretty significant kickback voltage when the stun gun turns off. Can a 50KV stun gun tolerate a back voltage of -50KV without toasting something (like the storage cap) in the stun gun?

Normally, a large inductive load (like a coil, motor, relay ...) has a diode wired across its input terminals to provide a path for the kickback voltage. In this case, you would need a diode rated at 10's of KV (whatever the voltage rating of the stun gun is), which are not very common.

This is one of those "it would be cool, and entirely logical" ideas that just won't work. If it did, you would be able to take a couple 5V transformers (from wall warts for example), wire them in series using the secondaries as the primaries. The 5V transformer is supposed to convert 120V to 5V (a 1:24 transformer action). Wired backwards it'll take 120V to 2880V (using simple minded ideas of transformer action). Send the output to a second transformer to get 69KV. Send the output to another transformer to get 1.6MV etc. Pretty simple. Pretty cheap, darn near free in fact if you use some of the old wall warts you have laying around the house.

Nope, won't work. What will happen is the first transformer will actually give something close to 3KV though it'll get hot and may melt its insulation if run too long. The second transformer will either spark internally across the windings or across its contacts since its insulation was not designed for voltages much above a couple hundred volts let alone ~70KV. Simple idea, apparently logical, but it won't work.