No Subject

[Jim Cook]

>Excuse my ignorance, but do 'Splitfire' sparkplugs fall under the
>heading of being multiple-spark devices? Do they spark twice at the same
>time, or sequentially (as MSD systems appear to do). And do they
>actually have any benefit? (obviously, racing rpm's are going to be
>well in excess of 3500, but I assume multiple-sparks enhance fuel
>economy at the lower RPMs).

>William

As I understand it, the Splitfire does not fire multiple times. It is not a 
multiple spark device in itself. However, its key advantage is supposed to
be its multiple targets. As a normal spark plug "wears" the electrode edges
become rounded and/or contaminated. The rounded edge increases the gap and 
contamination from combustion increases the resistance, both of which can
lead to a misfire. A side note to this is that is a natural phenomena that
the spark likes to jump from an edge. This can be seen on a new spark plug.
The spark will source from the edge of the source electrode rather than the
center even though the surfaces are paralell. This has been referred to as
"skin effect" the theory that electrons travel on outer surface of a wire
more so than the center. I suppose it is possible for the spark to change
which target electrode it is using in a single firing as the spark does have
a finite length. However, it would still be a single uninterrupted spark.

Additionally, I would like to thank Bruce Bowling for turning me on to the
EFI mailings. I have been on this list for about a month. I am an EE that
worked 10 years as a mechanic. I have the same list of questions that I 
posted directly to Bruce coming this way soon.


Jim Cook