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Old 03-30-2010, 01:25 PM   #1
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Default Explanation: Temp and Humidity Effect On Tune

I know muchmore and other companys have come out with basic weather stations for pits... can someone explain the changes in temp and humidity and how they correlate to changes on your tune? i.e. high humidity change this , high temp low humidity change this etc.

thanks
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Old 03-30-2010, 01:46 PM   #2
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I'm sure there guys out there more versed in this but this is what I know

cold weather will make the engine run leaner. Hot weather will be the opposite. These are in a given humidity.

wet air also makes for a rich tune

Hope that helps
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Old 03-30-2010, 01:57 PM   #3
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I don't know too much about humidity, but as Casey said...

Colder air is more dense, meaning it contains more oxygen. What this means is for the same amount of air you need more fuel achieve the ideal fuel/oxygen mixture.

The opposite applies for hotter air. Hotter air is less dense and contains less oxygen. What this means is for the same amount of air you need less fuel to achieve the ideal fuel/oxygen mixture.

We can assume that the air flow into the engine is the same in either condition, because that is limited by the carburetor.

In other words cold air makes your tune leaner and you must richen your tune to compensate. Hot air makes your tune richer and you must lean your tune to compensate.

Humidity adds another factor to the equation, and I don't know enough about that to go into detail.
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Old 03-30-2010, 02:27 PM   #4
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Another factor to take into with tuning is elevation.
The more the track is above sea level,the thinner the air.
Thinner air,less oxygen,less fuel required to keep the ratio correct and
vice-versa.
How much depends on engine etc?

Hope this helps.
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Old 03-30-2010, 02:36 PM   #5
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Found it, an absolute gem IMO.

http://www.rchobbies.org/cars_eng-tuning.htm
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Old 03-30-2010, 04:04 PM   #6
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Thanks everyone for all the responses... Special thanks to Neobart, that website was exactly waht i was looking for.

Joe G.
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