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#15: 02-16-2013, 05:18 PM
spark efficiency
 
 qiman
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Quote:
Originally Posted by DOHCEJ22E1 View Post
This thread now has my attention.
$15 & a more complete burn can be had?

I have one of those "fancy MSD coils" so I'm wondering how that would affect these non resistance plugs that you speak of (coil puts out 40k volts but amps I am not sure).

So what is the type of metal that these plugs have so that the electrode at the ends do not get eaten away? I have copper plugs & my MSD is chewing on them like you wouldn't believe.

Also, if there is too much of a spark, I would think that would mean an increase in octane so that the combustion chamber would stay cooler to avoid detonation but if anything I am saying is not making any sense, please let me know.

I'm just working off my basic understanding of how spark, air, & fuel come together for combustion.
Yes, more complete burn.

40kv is more than that MSD 33000v one some people are putting on their Subaru's that are meant for the Neon and Eclipses. What is the coil you're using? Is your engine similar to a EJ25 wasted spark ignition?

The outcome of coupling that non-resistor plugs and your higher voltage ignition is that the spark will be stronger at the plug.

With the plasma, the plug material is much more important. Ideally, it would have tunsten at BOTH the center electrode and the ground. Tungsten was common back in the early 1900's - search ebay and you'll see that. Plug manufacturers won't make them anymore because the plugs will outlast your engine and they won't sell very many. Most of the exotic metal plugs are just distracting people from going back to the basics of what always works best. Tungsten is inert and is a great catalyst for chemical reactions - doesn't add to or take away from the chemistry and it won't corrode.

But for performance ignition coils, cdi's or msd's, most normal racing plugs metals work fine. They won't have as long of a life compared to stock ignition coils and resistive wires/plugs. Beryllium/copper is a good alloy that we've tested and some places make them avail. They brisk yttrium a-line non-resistors with the 4 ground electrodes last pretty good. The "torquemaster" plugs now know as Extreme Spark last a long time. I don't have specific experience with those and Subaru's so I'm on a learning curve here and am just starting with the v groove racing plugs from NGK.

This isn't the exact numbers, but or example, if you put in 12v and 1 amp into your ignition coil, it will fire at HV when the switch is turned off (inductive collapse or radiant spike). 12v at 1 amp is 12 watts input - I don't know how much a stock subaru coil draws per spark. But this is the idea. If there is 10% loss in the autotransfomer windings (the coil is a small Tesla coil) - you have 12 watts minus 10% loss = 10.8 watts available.

10.8 watts divided by your 40,000 volts output = 0.00027 watts. You traded low voltage and high current for high voltage and low current. If you find how much current your coil draws per pulse, you can then use the above math to figure out the current. Imagine that small of current most of it destroyed in cable and plug resistance. It is no wonder a stock spark is like a fine spider web at the gap of a plug.

Here are some comparisons.

As you can see, the standard Kettering Spark Ignition can be as low as 0.01% efficient in converting power to a spark at the gap, which runs almost every gasoline powered engine in the world. Peaking Capacitors are MASSIVELY more efficient at converting the standard spark ignition power to a spark - upwards to 50% efficient! Notice that is 50% and NOT one-hundredths of one percent. That is quite a difference, but is all the hype justified? Capacitive Discharge Ignition systems have a separate power supply and are the prime choice for serious results. The dense blue ball at the gap is substantially more powerful than the peaking cap but it is hard to tell from the picture. __________ IGNITION method uses the SAME amount of power as the CDI system but is so much brighter and more powerful that it is beyond words. It isn't even a spark or an enhanced spark - it is in a category all by itself - it is a bright white ball of wonder!
I deleted my name because I'm not here to plug my stuff - pun intended. lol

Kettering is normal spark ignition. Peaking caps are a capacitor in parallel across the gap of a plug. For example, Pulstar plugs are nothing more than peaking caps built into the plug and the Nology wires are just capacitance built into the wire to do the same thing - they're just discharges slower so the spark lasts longer. CDI is normal capacitance discharge like any CDI or MSD - MSD of course just being more CDI discharges per cycle.

Now, for the EXACT same energy that the CDI takes and you can see the CDI is really not that much different than peaking caps, I get that supernova at the spark plug gap - SAME ENERGY! I just know how to manipulate electricity to do what I want. But that effect won't happen if there is any significant resistance in the plugs and cables.

Anyway, you say your MSD is chewing up your plugs, but it is an actual MSD or is just an MSD manufactured coil? If it is just the coil and it is 40kv output and your plugs are getting chewed up, I'd say the plugs are junk. With plugs I've used throughout thousands and thousands of hours of bench testing ignitions, I've never seen an ignition coil chew up plugs and I'm used to using a Mallory Promaster that is about 70-80kv!

With octane, actually if you have a more efficient ignition, you can use a lower octane. A better ignition doesn't necessarily mean hotter temperature either. For example, with the plasma ignition, (real plasma like I show above and not just bigger normal sparks), the engine temperatures have shown to drop up to 100F or more! AND, that is even with leaning out the mixture.

There is a huge misconception about lean burn and engine temps. If you lean it out a little and haven't compensated for a way to burn that lean mixture more efficiently, then yes, you can get hotter temps. However, you can take it so lean and with plasma for example, the engine runs cooler and cooler.

Just look at the famous story about Charles Lindbergh -

http://www.charleslindbergh.com/wwii/

You can read the whole story if you want, it is a fascinating bit of history about a famous lean burn method.

-------------------

Nervously the pilot told Lindbergh that he had only 175 gallons of fuel left. The civilian told him to reduce engine rpms, lean out his fuel mixture, and throttle back. When they landed, the 431st driver had seventy gallons left, Lindbergh had 260. They had started the mission with equal amounts of gas.

Lindbergh talked with MacDonald. The colonel then asked the group's pilots to assemble at the recreation hall that evening. The hall was that in name only, packed dirt floors staring up at a palm thatched roof, one ping pong table and some decks of cards completing the decor. Under the glare of unshaded bulbs, MacDonald got down to business. "Mr. Lindbergh" wanted to explain how to gain more range from the P-38s. In a pleasant manner Lindbergh explained cruise control techniques he had worked out for the Lightnings: reduce the standard 2,200 rpm to 1,600, set fuel mixtures to "auto-lean," and slightly increase manifold pressures. This, Lindbergh predicted, would stretch the Lightning's radius by 400 hundred miles, a nine-hour flight. When he concluded his talk half an hour later, the room was silent.

The men mulled over several thoughts in the wake of their guest's presentation. The notion of a nine-hour flight literally did not sit well with them, "bum-busters" thought some. Seven hours in a cramped Lightning cockpit, sitting on a parachute, an emergency raft, and an oar was bad, nine hours was inconceivable. They were right. Later, on 14 October 1944, a 432nd pilot celebrated his twenty-fourth birthday with an eight-hour escort to Balikpapan, Borneo. On touching down, he was so cramped his crew chief had to climb up and help him get out of the cockpit.


The groupís chief concern surfaced quickly, that such procedures would foul sparkplugs and scorch cylinders. Lindbergh methodically gave the answer. The Lightning's technical manual provided all the figures necessary to prove his point; they had been there all along. Nonetheless the 475th remained skeptical. A single factor scotched their reticence.

--------------------------------------

Anyway, despite their skepticism, the engines actually ran cooler, they used less fuel and there was no fouling of the plugs. A historical fact.

I know someone that ran an engine with an air fuel ratio of 100:1 on a bench test (not pulling a load) using a form of plasma ignition and the engine ran just fine to prove the point. For practical use, an AF ratio of 25:1 on a V8 with plasma worked just fine. That completely rips to shreds everything anyone thinks they know about the possibilities of a lean burn engine.

For example, most cars are about 20% efficient. That means 80% is wasted in transmission losses, etc... and bad combustion. Because of that, that means there is HUGE room for improvement in the combustion chamber. If we were all getting the energy in the fuel that we pay for, then cars wouldn't need a catalytic converter. With lean burn past 14.7:1, conventional wisdom is 100% wrong that you can't burn it. You can. It is a matter of using the right kind of ignition to release the energy from the fuel. That plasma instantly disassociates the hydrocarbon molecules on contact so it is almost like cracking heptane into propane, methane, etc... and suddenly you get more BTU out of the fuel. It isn't magic.

Anyway, I'm waiting for my custom cables and will look at upgrading my coil and adding a CDI that I can then modify to give me plasma. The NGK's won't last incredibly long but it is a test until I have some custom tungsten's modified.

Then, the path is to lean out the EJ25.

40MPG in the EJ25 on the highway with my 5speed should be a no brainer all the while, the engine runs cooler, no plug fouling, etc... I get 29MPG on the hwy with this 160,000 mile engine right now with a few simple things so 33% increase above that should be easy.

Mine is a 98 so is the last year with a MAF before they went to MAP. Does anyone know of a MAF modification to lean it out that doesn't including putting tape over the wire sensor or using a potmeter? Or, does anyone have the actual schematic so I can just build a new circuit?