New guy, quick ?
#11
Sorry I know that Neil I was just trying to explain the oxegen so I just disregarded the Hydrogen as not to confuse jason and help him understand what water in the air does. and niel the humidity thing is just common sense, expecially when you spend 10-15 years tuning nitro engines in R/C cars and helicopters these engines are very touchy and you can retune once a week or 5 times a day depending on the weather
Ken
Ken
Last edited by SavageKen; 08-16-2009 at 09:09 AM.
#12
Sorry I know that Neil I was just trying to explain the oxegen so I just disregarded the Hydrogen as not to confuse jason and help him understand what water in the air does. and niel the humidity thing is just common sense, expecially when you spend 10-15 years tuning nitro engines in R/C cars and helicopters these engines are very touchy and you can retune once a week or 5 times a day depending on the weather
Ken
Ken
That would mean it was being stripped from the hydrogen and I can't imagine that happening.
I though that it was the opposite.
In that some hydrogen from the fuel combines with some oxygen in the air to produce some water vapor that goes out the exhaust.
#13
OK,,, now I am confused. I followed what you said but it contradicts everything I know. I am running on the theory that water is not oxygen and hydrogen, its water. Therefore, it displaces the oxgyen. And even though the air itself is more dense, there is less oxygen.
I just did a quick search on the net and here is something I found. At first it seems to confirm what I said, then when you continue to read, it confirms what you said..........maybe I'll have to read it a few more times. I'm working now and my mind isn't 100% on this now, but I onced over it real quick and thats what it looked like to me
I just did a quick search on the net and here is something I found. At first it seems to confirm what I said, then when you continue to read, it confirms what you said..........maybe I'll have to read it a few more times. I'm working now and my mind isn't 100% on this now, but I onced over it real quick and thats what it looked like to me
The effects of humidty tend to vary with temperature. High humidity with low to moderate temperatures (say below about 50) will tend to make the engine run a bit rich, but the effect is pretty minimal. While high humidity at high temperatures will cause rich running and a loss of power.
Why a difference? It has to do with the saturation pressure associated with specific temperatures. Basically when water is a vapor in the air it exerts a pressure that becomes part of the total atmospheric pressure. So lets say it's your basic Chicago day in July it's 100 degrees (F) and it's 100% relative humidity . Because we are at 100% humidity it means we've reached the point where no more water will evaporate into the surrounding air (i.e the saturation point. That water vapor in the air will exert pressure (it's a gas now) of 1.93" hg. So if we have a barometric pressue reading of 29.00, only 27.07" hg will be exerted as AIR pressure. The lower density air would require less fuel to hold our air/fuel ratio at best power 12.5:1
If we left every thing else the same but dropped the temperature to 60 degrees, the water vapor would only exert a pressure of about 0.5" hg, so our actual air pressure would be 28.5" hg. The available air density would be MUCH higher at this temp. Higher density air means we need more fuel to hold our air/fuel ratio at best power 12.5:1
For a given temperature, as the relative humidty goes up the air pressure we can use to make horsepower goes down.
Basic rules HOT and HUMID lean it out a lot, Cool and humid MAYBE lean it a little. But keep in mind as the air temp goes up the ignition delay period is reduced and engines become more knock prone, so tread lightly.
Why a difference? It has to do with the saturation pressure associated with specific temperatures. Basically when water is a vapor in the air it exerts a pressure that becomes part of the total atmospheric pressure. So lets say it's your basic Chicago day in July it's 100 degrees (F) and it's 100% relative humidity . Because we are at 100% humidity it means we've reached the point where no more water will evaporate into the surrounding air (i.e the saturation point. That water vapor in the air will exert pressure (it's a gas now) of 1.93" hg. So if we have a barometric pressue reading of 29.00, only 27.07" hg will be exerted as AIR pressure. The lower density air would require less fuel to hold our air/fuel ratio at best power 12.5:1
If we left every thing else the same but dropped the temperature to 60 degrees, the water vapor would only exert a pressure of about 0.5" hg, so our actual air pressure would be 28.5" hg. The available air density would be MUCH higher at this temp. Higher density air means we need more fuel to hold our air/fuel ratio at best power 12.5:1
For a given temperature, as the relative humidty goes up the air pressure we can use to make horsepower goes down.
Basic rules HOT and HUMID lean it out a lot, Cool and humid MAYBE lean it a little. But keep in mind as the air temp goes up the ignition delay period is reduced and engines become more knock prone, so tread lightly.
#15
Hi everyone, Im new to the KLX 250 and dual sports. I live near Greenville, SC and cant wait to ride in the mountains just as soon as I can get my tag. I have a ?, how can I determine if my bike is a California spec bike or not, I bought it in NE Georgia. I pulled the airbox lid off and now it bogs down when giving fuel quickly.
Thanks for the invite Deej.
Jimntr.......
Thanks for the invite Deej.
Jimntr.......