Plasma Ignition | Plasma Jet Ignition

[Floris]

Yes Aaron, single discharge will happen if you use a high enough trigger frequency. As far as I know it it not an option to be set. I use a reed switch and a monopole to trigger the MSD unit. Once you get it running fast, discharge will drop to a single one.

Are there any plugs with tungsten electrodes out there? Would like to hear some suggestions to try.

Good luck.

The plugs have always been an issue - needs to be tungsten on both electrodes.

Some plugs last longer than others but can last a lot longer than 2 hours. One partner tested some that lasted a several thousand miles.

You say "single discharge" - can you set your MSD to single discharge instead of multi? I need that option for something else and am having a hard time finding a regular CDI with single discharge.

[Aaron Murakami]

Yes Aaron, single discharge will happen if you use a high enough trigger frequency. As far as I know it it not an option to be set. I use a reed switch and a monopole to trigger the MSD unit. Once you get it running fast, discharge will drop to a single one.

Are there any plugs with tungsten electrodes out there? Would like to hear some suggestions to try.

Good luck.

Thanks - ok, that is the same with all the MSD's just because the charger can't keep up at those speeds.

No off the shelf ones that I know of but a few people do put some custom tungsten plugs on ebay once in a while. Way overpriced, but they are sometimes avail.

[nte]

On MSD switching to single discharge

MSD has been around for a long time, and their trademark and name come from an ingenious and straightforward technology, Multiple Spark Discharge.

MSD's technology does 3 very important things different than your stock ignition:

First, it will fire up to 12 individual sparks over a 20 degree crankshaft rotation below 3000RPM. This is much more and much longer duration than any stock system i'm aware of. What it does is burn more of the fuel injected into the cylinder. This in turn creates more horsepower, better gas mileage and reduced emissions.

Second, above 3000rpm it's hard to discharge more than one spark per rev, so instead, it keeps one long, hot spark burning for that same 20 degrees.

Third, with a "diamond" coilpack from a newer Subaru, the extra spark power the ignition serves can be enhanced by the better coil. The DIS increases the spark energy much more than the stock system so that the spark is much hotter and can burn the air-fuel mixture much more completely. Note: A 2.5RS coilpack is NOT necessary, any pack with the "Diamond" logo on it will work better than the earier ones. Any 95+ 2.2 or 2.5 should have these.

http://user.xmission.com/~dac/library/DIS.htm

MSD makes a multiple spark capacitor discharge ignition system widely used by Mazda rotary engine racers but it only works up to 3000 RPM. After that it is "one strong spark" says MSD. Not enough IMHO."

there is another company called AEM that make MSD systems. I called them it too does not fire more than once past 3000 RPM according to the electronic tech guy. He kept saying there was not enough time

http://www.rotaryeng.net/Why-CDI.html

[Floris]

Are there any plugs with tungsten electrodes out there?

To answer my own question, actually NGK has tungsten electrode sparkplugs! The surface gap type like the BUHW are the ones I found but there are more, might be just what I need

[Aaron Murakami]

To answer my own question, actually NGK has tungsten electrode sparkplugs! The surface gap type like the BUHW are the ones I found but there are more, might be just what I need

What is the plug part number?

[nte]

NGK 2622 BUHW Tungsten Spark Plug

http://www.ngk.com/product.aspx?zpid=9590

[Aaron Murakami]

Would just have to test them. If they're non resistor - then looks like a good deal!

But it also depends on the polarity of the HV ignition coil.

[nte]

The BUHW plugs don't have a resistor but do have a short reach.

[serendipitor]

I'm late to the party. It seems like things have calmed down.

I wanted to add a comment about this effect which has not been mentioned. That is, it has a very sharp threshold with respect to the voltage on the capacitor. Very much all or nothing. In my setup, using a standard 10K ohm spark coil, 40uF cap, and 15 1N4007 diodes in series, I need to be above 130V on the cap to get a plasma discharge. Below that it is just a simple spark. Above that, it is like an avalanche conduction.

Quite interesting, negative resistance. I would like to know what changes so dramatically to initiate the effect, with such a small increment of voltage. Since there is already a simple spark well below that 130V threshold, it is not about the air being ionized.

Here are a couple of scope shots of the voltage across the capacitor, that show first the subplasma threshold, and second the plasma effect. The first shows that there is still some flux left after the spark has ceased, which oscillates a bit until the energy dissipates. The second shows a steeper fall time, and very little flux left over at the end of the spark.

[1w9m8b9]

Hi there! New to this forum, and having some trouble getting the plasma effect. Have an MSD Street fire CDI, the same one Aaron used, and coil of the same brand. Hooked up to a 12V battery with no switch or anything- I'm just touching the wires to trigger the spark.

Got lots of pretty purple sparks but as soon as I hook up the diode I stop getting sparks and I hear a soft kind of buzz/click coming from somewhere. Not sure if its coming from in the CDI or from somewhere else.

The diode is a microwave oven diode, silicon rated up to 15kV, 50A surge. Even tried hooking 5 of those diodes up in series and the same thing happens. Also tried reversing the diodes and hooking them from negative to negative in case the coil was making a negative spark, but didn't work either.

Plug is non-resistor, solid copper core.

Anyone have any idea what might be happening? Any advice would be much appreciated.

[Aaron Murakami]

Hi there! New to this forum, and having some trouble getting the plasma effect. Have an MSD Street fire CDI, the same one Aaron used, and coil of the same brand. Hooked up to a 12V battery with no switch or anything- I'm just touching the wires to trigger the spark.

Got lots of pretty purple sparks but as soon as I hook up the diode I stop getting sparks and I hear a soft kind of buzz/click coming from somewhere. Not sure if its coming from in the CDI or from somewhere else.

The diode is a microwave oven diode, silicon rated up to 15kV, 50A surge. Even tried hooking 5 of those diodes up in series and the same thing happens. Also tried reversing the diodes and hooking them from negative to negative in case the coil was making a negative spark, but didn't work either.

Plug is non-resistor, solid copper core.

Anyone have any idea what might be happening? Any advice would be much appreciated.

Can you post some pics and exact diagram of what your setup is?

You definitely should only have to use 1 of those diodes.

[1w9m8b9]

Wow thanks for the prompt reply. Sorry, should have posted pics to begin with. Having trouble getting some of them to upload through this forum, so I'll post a link to my photobucket in case that doesn't work either.

http://s1368.photobucket.com/user/wh...tion%20Project


Really excited to get this working and see what kind of mileage I get get by combining the plasma with a gasoline fume intake system. If you haven't heard of running on fumes, you should check it out. Guys are claiming 200mpg or more by routing gas fumes straight to the carb. Here's a video of it some guy made: https://www.youtube.com/watch?v=ZFxwJ8mIDtA

[Aaron Murakami]

Wow thanks for the prompt reply. Sorry, should have posted pics to begin with. Having trouble getting some of them to upload through this forum, so I'll post a link to my photobucket in case that doesn't work either.

http://s1368.photobucket.com/user/wh...%20Project


Really excited to get this working and see what kind of mileage I get get by combining the plasma with a gasoline fume intake system. If you haven't heard of running on fumes, you should check it out. Guys are claiming 200mpg or more by routing gas fumes straight to the carb. Here's a video of it some guy made: https://www.youtube.com/watch?v=ZFxwJ8mIDtA

Ok, looks like they changed a red to orange.

Looks like you have it setup right.

Big red and black to battery.

Little red (orange) and black to coil.

Ignition red to battery +

White wire just needs to be dropped to ground of battery and of course the ignition coil neg needs to be connected to the battery negative - I would make sure it is not just going back to the negative of the wire on the negative of the coil.

Does it work without the diode in normal MSD mode?

[1w9m8b9]

Just checked the wiring and ran it again. Ignition coil negative is going back to bat negative. CDI is still fully functional when the diode is not hooked up. With diode in place there is no spark just a buzz/click that I'm now pretty sure is coming from inside the CDI. I'm thinking there might be a short going on somewhere inside from the increased current; got this off ebay and it might be refurbished - going to take it apart once I can find the right bit, but not exactly sure what to look for once it's open.

In case I can't get it working, would you mind sending me or pointing me towards a schematic for a simple CDI that would work for this purpose that I can take down to the electronics store and build myself?

[Aaron Murakami]

Just checked the wiring and ran it again. Ignition coil negative is going back to bat negative. CDI is still fully functional when the diode is not hooked up. With diode in place there is no spark just a buzz/click that I'm now pretty sure is coming from inside the CDI. I'm thinking there might be a short going on somewhere inside from the increased current; got this off ebay and it might be refurbished - going to take it apart once I can find the right bit, but not exactly sure what to look for once it's open.

In case I can't get it working, would you mind sending me or pointing me towards a schematic for a simple CDI that would work for this purpose that I can take down to the electronics store and build myself?

If it works in normal mode without the diode, it should be fine.

It is possible the diode is blown. If the diode is good, the ignition coil might have a negative hv polarity. I actually am not using a stock black ignition coil for anything - been a long time anyway.

You mentioned hooking diode from neg to neg but if the HV is neg, you actually want to keep the diode in the same location between ignition coil + and HV, but just reverse it in the opposite direction. Try that and let me know what happens.