Getting the best engine performance means choosing the right glow plug, which depends on a number of different factors - the engine type, air-fuel mix, nitro percentage, and even air temperature. What's more, the right glow plug will change as conditions change. Keeping a range of glow plugs on hand will help you fine-tune glow heat and enjoy Maximum performance under all conditions.
Generally, hot plugs provide better idle and acceleration than cold plugs. Cold plugs will produce more power but may idle more roughly and be harder to tune.
The "right" glow plug for your engine is the one that gives you the best performance. And you can choose the right plug for any situation, just by following the guidelines below.
1. Engine Type
Standard engines (engines with a 1-piece head) are most common. Standard plugs are easily available, inexpensive and fit almost all standard engines. Standard plugs are installed with a washer, which creates a compression seal with the head.
Many new engines are turbo engines, which feature a special 2-piece turbo head. The biggest benefit of turbo plugs is superior performance. Unlike standard plugs, turbo plugs feature a tapered "seat" that matches perfectly with the head. That creates a superior compression seal and with it, Maximum efficiency and power. Turbo plugs are the choice for racers who want - and need - top performance.
Guideline 1: Know what type of engine you have. Is it a standard - or a turbo? 2. Displacement
Size matters to glow plugs. What size is your engine? A .12? .15? .21? Big engines have more mass and retain heat better. Smaller, lighter engines don't, and need the help a hotter plug can offer.
Guideline 2: The smaller the engine, the hotter the plug. 3. Fuel Nitromethane Content
What's the nitro percentage in your fuel? High-nitro fuels produce more power than low-nitro fuels, but also produce more heat.
Guideline 3: The higher the nitro content, the colder the plug. 4. Temperature
Smart modelers tend to keep a variety of glow plugs on hand. The reason? Because the "right" plug for your engine can change with the temperature. To achieve top performance, your choice of plug needs to change, too.
Guideline 4: The hotter the day, the colder the plug."