[dsn_klr650] spark plugs, resistor/nonresistor

[Chuck Tanner]

Now I am definitely no expert in this area so the rambling that follows is just so I can see my text on the list. I realize that resistor type plugs cut spark intensity but how does this equate to inefficiency? I have often looked at it this way. I could hook up a haphazard voltage source (that you might find on a KLR) to a circuit with no inline resistance to perform some function say light a bulb. Now the bulb in this case is obviously a type of resistor but lets ignore that point! SO I turn on the power and the bulb lights very brightly but I notice that it is not regulated well in that it seems to dim and flicker but is still quite intense overall (intense but inefficient). I decide that while this bulb burns brightly it is annoying to have the inconsistency of a brightly flickering light (I cannot rely on a reproducible effect). Something in the circuit (be it power supply or wiring) is allowing these surges in energy and if I found just the right inline resistor to hold the bottom end (or a compromising middle end) of those surges I might get a more consistent lighting effect thus extending the life of the bulb and decreasing the inefficiency of the circuit's primary function. Given that, I can now always perform my job under a "constant" (light source in this case but how about spark for a plug) so that any thing I do (or anything I do to my KLR) is unrelated to the prior inefficiency. To extend the analogy, I would now have a plug (the resistor plug) that fires a slightly less intense spark but with much less variable magnitude. Now, I don't know how well voltage is regulated to the plug in the KLR but the resistor type plug could even things out in terms of the reproducibility of the sparks intensity. This would lend itself to easier fine tuning else where when considering the overall inefficiency of the engine. But, in a thumper spark variability may not be a big deal in overall tuning. What do I know? I deal with human performance not engine performance! Chuck A14 i read the following in an article by some SandiaLabs scientists (full article available on http://www.directhits.com/AdvAutoIgnSys.asp ********************************************************************** It is useful to model the circuits and compare the energy transferred to the spark with varying amounts of resistance in the high voltage section of the circuit. Figure 1 shows a schematic of a typical capacitor discharge ignition system. Representative parameters for conventional and three different power enhanced ignitions are shown in TABLE 1. Note that Conventional ignition circuits have high resistance in the secondary side, often as much as 25 K ohms, which limits transfer efficiency to the spark to around 0.2%.