Which glow plugs for which engines and applications?

A cold plug should be installed in engines with high displacement, during full throttle operation, when using fuels with a high nitromethane content, in high ambient temperatures, or with poor cooling.

Medium "standard" plugs are recommended for low fuel nitration, in engines with low compression and power, etc. The medium glow plug type is usually the most cost-effective all-round plug and should be the first choice when tuning for the specific engine type.

Hot glow plugs are advisable if the engine has poor idle characteristics, when little nitromethane is used, in engines with low displacement, in very low ambient temperatures, or when the engine is predominantly operated in partial load conditions.