Re: whats the effect of running poorly gaped plugs?
"Copy and paste from NGK"
Gap size has a direct affect on the spark plug's tip temperature
and on the voltage necessary to ionize (light) the air/fuel mixture. While it is a popular misconception that plugs are pre-gapped from the factory, the fact remains that the gap must be adjusted for the vehicle/engine that the spark plug is intended for. Modified engines with higher compression or forced induction will typically require a smaller gap settings (to ensure ignitability in the denser air/fuel mixtures). As a rule, the more power you are making, the smaller the gap you will need.
A spark plug's voltage requirement is directly proportionate to the gap size. The larger the gap, the more voltage is needed to bridge the gap. Most experienced tuners know that opening gaps up to present a larger spark to the air/fuel mixture maximizes burn efficiency. It is for this reason that most racers add high power ignition systems. The added power allows them to open the gap yet still provide a strong spark.
