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Spark Pug help for Supercharged motor

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Which one is better out of these and what gap should I use? I don't know if 3 and 4 are the same since one say's copper ?





1.......... NGK TR6-IX Iridium Spark Plugs, One heat range colder than stock, gapped at .035 (Works well in extreme conditions, such as Nitrous, Supercharger, or High-compression motors)


2...........NGK Racing R5724-9 Spark Plugs, four heat ranges colder than stock, gapped at .036


3............NGK TR6 Spark Plugs, One heat range colder than stock, gapped at .035 (Works well in Nitrous, Supercharger, or High-compression motors)


4............NGK TR6 Copper One Heat Range Colder than stock - Recommended Gap for Nitrous or Supercharged is .035"

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i run the non iridum tr6 gapped to .035 ive been thinking about changing it to .030 and see if it helps at all since i upped my dwell . i think 3 and 4 are the same though. the iridiums are not needed but will last a bit longer, i just dont mind changing the plugs every other oil change. so i went with the regular tr6 plugs.

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man i just did alot of reading here was one of the best explinations i found


Electricity is simply the movement of electrons. In order for electrons to pass from 1 atom or molecule to another, the particle must be ionized, or give up or accept 1 or more electrons leaving the particle with a positive or negative charge and NOT neutral like they prefer to be. It takes a finite amount of energy to be able to ionize any particle.


If you have a 0.060" gap there are more actual molecules between the positive and negative parts of the plug (anode, cathode) that there is in a 0.030" gap. Having more molecules between the electrodes means you will need more electricity to be able to ionize enough molcules for the spark to jump the gap.

The more compression, be it by static compression(ie 9.0:1), or boost(turbo supercharger) or chemically(ie NO2) an engine has the harder it is for a spark to jump the spark gap. All of the things listed above are means of raising combustion pressure, (therefore pushing harder on thepiston for more power), increase the number of air/fuel atoms and molecules that are present between the 2 electrodes.

Since it takes a certain amount of electrical energy to excite these particles enough for them to give off their electrons, the gap cannot be too large. Or in other words there cannot be TOO many particles in between the electrodes or the spark cannot jump the gap. This explain why when using power adders on an engine requires either smaller plug gaps and/or a higher output coil.

So TOO many particles between the electrodes with not enough voltage and the spark wont jump the gap.

You apply the power from the coil to the plug gaps, as the electricity travels from the cathode to the anode(or vice-versa?) it must pass thru the a/f particles, each particles energy level or level of excitation rises, when its at its highest it kicks off an electron to the next particle, this electron makes the next particle excited as well so it kicks off an electron to regain stability, this goes on until the spark reaches the other electrode. As the particles regain their stability after kicking its extra electron to its neighbour, the particle relases energy in the form of heat and light(thermal,& radiation). It is this heat which starts the burning of the fuel and air mix and forms a kernel around the spark gap and then the flame front travels outwards combusting fuel along the way. The more complete and hotter the burn, the higher the cylinder pressure spike and the less unburned fuel is left over then gives you the most power with the least amount of polluntants possible.


If you have TOO small of a gap, not enough molecules of air and fuel will be exposed to the spark to continue the flame front to all parts of the chamber and an incomplete combustion of the a/f charge will result. I beleive the area around the sparkgap which is ignited first by the spark is called the flame kernel, the flame kernel then ignites other a/f particles and the burn continues to the rest of the chamber. As the flame front covers the entire chamber, the cylinder pressure rises quickly and pushes the piston down.


Its a balancing act with plug gaps, too large, the spark wont jump, too small, you get a poor flame kernel then a poor flame front and then poor rise in cylinder pressure which means poor power.


I think that if you could measure the actual temperature of the spark and compared a plug gap of 0.060" and 0.030", you would find that the large gap would be highest simply because there are more particles being excited into instability, then releasing heat and light as the particles return to their stable original forms.


but running them at .035 you still have the possibilty of blowing the spark out, which is why the reason th go to a smaller gap the fix for that is to increase the dwell time of the coils. you just start charging them sooner and longer and the spark gets hotter and will prevent spark blow out. the down side is reduced coil life so you dont want to go too much dwell, just enough to prevent blow out.

Edited by 04CHASE (see edit history)
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