plugs & hp increases

[Thomas Wright]

Andrew Rabbitt wrote:
> 
> > if the platinums run hotter then, if the system were at it's
> > limit, it'd start to detonate or pre-ignite (can't get that
> > straight  8^)  ....
> >

supposedly, bosch platinum plugs have a more broad heat range than most
other plugs.  For example, the platinums in my car (I can't remember the
part #) were a replacement for Champion NY 10 through NY 12.  I wouldn't
think that there would be a heat range problem with platinums.

> If you get pre-ignition, it doesn't matter what spark-plug you have,
> 'cos it's not doing much for you! :)

a plug that is in too high high of a heat range will *cause*
preignition.

> 
> > and combustion chamber design affects
> > things like that, so different types of engines could
> > conceivably not like platinum plugs ..... just a thought
> >
> I suspect what's happening is you're changing the burn rate, which
> effectively changes the ignition angle (sort of).  Since most cars run
> retarded at idle (to maintain catalyst temps and reduce combustion
> noise), if you slow the burn rate down further (by changing plugs), you
> could fall off the ragged edge, hence the unstable idle control.
> 
> This is just a theory, of course.
> 
> Andrew Rabbitt