Selecting the right glow plug depends of several different factors, from your engine to the environment. Be sure that you fit the correct plug or you may damage your engine.

Standard or Turbo Glow Plug?

The most common engines are the one piece head engines, these use standard glow plugs, which use a washer to keep the engine air tight.

There are a few engines which take the turbo glow plug, the only difference is that the plug is tapered at the end, this is called the seat. This tapered glow plug matches perfectly with the head and gives superior compression and hence a little more power. The turbo glow plug doesn't have anything to do with a turbo from a real car, it's just the name they share.

The size of your Engine

Displacement plays a big part in selecting the correct plug, the larger the engine the more heat it retains due to it's size, because of this big engines need cooler glow plugs. A smaller engine on the other hand needs a slightly hotter glow plug to run at it's optimal.

The % of Nitro in your Fuel.

More nitro will give you more power, which in turn delivers more heat, the higher the percentage of nitro in your fuel the cooler the glow plug needs to be.

The Track and Air Temperature

Same as the above, your radio controlled nitro car will run hotter on a hot day, use a cooler glow plug to keep the timing or your two stroke in line.

So what's the Difference between Hot and Cold?

Hot plugs tend to give better idling and the acceleration is also improved slightly, if you have a sluggish car that struggles to idle then you might want to try using a hotter glow plug in your 2-stroke.

Cold plugs are more difficult to tune and tend not to idle as well as hotter glow plugs, but over all performance once the car it in tune can be slightly better than when you use a hot plug.

What about the track?

If the track has a lot of long straights then a colder glow plug will work best as you'll be reaching max RPM often, if you find your not reaching your max RPM then a hot glow plug will help get a little extra performance mid-range.

The mixture

If you run too lean the glow plug will burn out, if you run to rich the glow plug will get coated with oil and not perform correctly, while it's always better to run a little on the rich side, a glow plug needs a good tune to perform correctly.

Your glow plug can tell you a lot about how your radio controlled car is tuned, although this only works for the first few runs, see the glow plug reading guide for more information.

Conclusion

Selecting the right glow plug can only come from experience, use this guide as a starting point and if your not sure find out what the other racers at your local track use and start there.

If you select the wrong plug you can damage both the glow plug and the engine, your first sign is that the car won't be running correctly, if this is the case pull her off the track and check for problems, don't keep her out and hope the problem goes away, it never will.

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