One point that is often left out of these "bigger gap in the circuit" discussions is that most of the *energy* delivered by the ignition system gets released in the spark that is jumping the biggest gap. So... while an extra gap may force the coil secondary voltage high enough to fire a terribly fouled spark plug, the *energy* (and thus the ability to reliably fire a the mixture) delivered to the plug is far less than a CLEAN plug with with absolutely NO other gap in the secondary circuit, and most of the energy is being wasted in that extra gap. IOW- adding spark gaps to the secondary side is a half-assed band-aid for a problem that should be fixed instead of patched. That is also why DIS systems are superior to distributors, even though distributor systems (artificially) force a higher peak voltage in the secondary, all other things being equal.
Daniel J. Stern wrote: