General question regarding tuning

[CaptainMTM]

So I'm new to RC nitro and have a general question regarding tuning. Let's assume I come up with a good tune/adjustment for the buggy (needles are set just right) and then I start bashing it around in different temperatures (when it gets colder). Will this require a readjustment of needles? How much does change of temperature affect the performance of the engine and how much of an adjustment will be required? Typically speaking, will the engine have a tendency to start running richer or leaner when temperatures drop significantly? Basically I'm just trying to figure out what to watch out for as the seasons change and I definately don't want to run my car too lean and hot.

Lastly, I read everywhere how it's a good idea to insulate the cylinder and avoid breaking in your engine when it's cold outside but I never got a definition of what's cold. Does it refer to when the temperatures drop below 0 C (32F)? I guess my question is at what specific temperature do I have to start worrying about protecting the cylinder and taking other measures for break in? It's going to be around 13-14C (57F) this weekend and I want to know if to take any measures.

Thanks in advance for the help!

 

[Lessen]

Alrighty...

Air becomes more dense with decrease in temperature, that means the air has more oxygen per volume of air when it is cold than when the same volume is warm. When the temp goes down and the oxygen levels (per a given volume)go up you will get a "lean" condition (Lean= too much oxygen per a given volume of fuel). The opposite is true of a "rich" condition. So basically when the temperature gets colder you need to compensate by creating a slightly more rich fuel/air mixture. Likewise, when the temperature gets warmer you need to compensate by creating a slightly more lean mixture. As far as how much you need to adjust.. that depends on your engine. Every engine and carb combination reacts differently to changes. Just do them a little bit at a time (1/16 or 1/8 turn on the HSN).

I think as long as you keep the engine's running temperature up around 200 or slightly more you will be ok. However, you must consider that the colder the air is the richer the mix will need to be just to run. Of course you want to be somewhat rich anyways when you are breaking in a new mill but if you adjust too rich because you are attempting to compensate for extremely cold air you run a higher risk of over-stressing engine components because of the excess fuel additives. Nitro fuel contains a lot of oils for lubrication and cooling purposes. The more fuel you introduce into the combustion chamber the more oil will be there as well. An excessive amount of oil will not compress as well and if there is too much it stands to put too much stress on the engine possibly aiding in a part failure such as the connecting rod.

 

[Monkey Wrench]

Well, I'm not "Bill Nye the Science Guy" like Lessen is (though he is dead on accurate) but when I run in the winter, I wrap the cooling head in a piece of bicycle inner tube to keep the temp's up. No, it won't melt onto the head at all, so no need to worry. Usually I use the tube when the temperature is around 40-45 degrees or lower. I also richen my HSN a tad or so as well, just to be safe.

Hope this helps!

 

[CaptainMTM]

Thanks for the tips guys

 

[Metalhead Matt]

Start your engine warm. Heat it with a hair drier if it hasn't been sitting in a heated space. Nitros HATE the cold.