list:

not so fast. first, in reality, plug is unlikely to spark to more than one
ground electrode at a time. but if did spark to all 4 ground electrodes
simultaneously, the resulting resistance of the plug might actually be
higher! whereas the resistance might drop from essentially infinity to say
a thousand ohms as a single spark intensifies, dividing the spark energy
between 4 simultaneous sparks would lead to reduced ionization, and
perhaps a much greater resistance(s) per gap because of the lower peak
spark currents. the coil is not a power supply, and the problem is a
complicated transient phenomena. initially spark current is limited by gap
resistance. at its peak spark current is usually limited by secondary
circuit resistances.

in any case, there is flat out no mechanism to damage a coil by using
multi electrode vs single electrode spark plugs. and, there is no obvious
desgn change even for the purpose of optimizing a coil for one or the
other plug type.

dan

On Sat, 12 Jun 2004 11:48:44 -0400, David Brodbeck <gull@GULL.US> wrote:

>On Sat, 12 Jun 2004, Ken Lewis wrote:
>
>> Scenario 2(quad tip).
>> To me, if you provide four paths to ground then the impedance of the
plug
>> becomes R/4 since said paths are in parallel. Substituting into above
>> formula you get Power=4*V^2/R or four times the power is required from
the
>> coil.