Ideas on stoppin some pingin?

[Bruce.Hearn@cd-tech.com]

Long-time lurker Zak wrote:
>The cooler and denser the intake charge,
>the cooler the in-cylinder temperature.

Cooler is better, denser is not as regards detonation tendency.

>The reason you'll sometimes hear detonation at
>low RPM in a high gear when the car is lugging,
>but not at higher RPM is the speed of the combustion cycle...
>If your combustion cycle increases speed,there
>isn't enough time for the unburned end gases to ignite
>before another cycle starts.

Oddly enough, combustion coompleteness is not related to engine speed.
Until you reach stratospheric engine speeds (20k+ rpm), combustion always
has time run its course.  Why?  As rpm increases, intake velocity increases
and causes greater turbulence in the combustion chamber.  As turbulence
goes up, so does air and fuel mixing.  Better mixing allows for faster
CONTROLLED burn.  Counter-intuitive, but that's what Charles Taylor ("The
Internal Combustion Engine in Theory and Practice") found.  In the end,
though, Zak is correct in that raising rpm will reduce detonation.

If possible, avoid aromatics like benzene, toluene and xylene as they are
biologically nasty and form soot and subsequent carbon in the combustion
chamber, aggravating any knocking tendencies.  The EPA is working towards
removing aromatics from gasoline.

Bruce in Houston