Optimum Ambient Temperature For Motor When Riding

Sparks66 · Dec 12, 2009

Hi,
I see these posts where people talk about performance issues dictated by the air temperature.
So, what is the ideal air temperature for the motor when riding, and happens to engine performance when the air temperature is too hot or too cold?
Sparks

Venice Motor Bikes · Dec 12, 2009

These bikes run the best when the air is cold & dry!!

Terry Blow · Dec 13, 2009

Cold air makes horse power the quest for more power has been going on since the day gas powered engines where invented. Over the years one of the way they have found to make more horse power is with cold air. In the 60's they found all kinds of creative ways to get more cold air to car engines and hood scoopes where borne. Many years later technology stepped in and now they use after coolers and intercoolers I beleve that it gose like this cold air is more dense and containes more oxygen and an extreme version of more oxygen is nitrous oxide witch is just that more oxygen = more power hope I'm not too far off and I hope this helped

Terry

bairdco · Dec 13, 2009

the ideal temperature for my chinee motor is precisely 298.555 degrees Kelvin, with an absolute humidity of 16.6 grams per meter cubed, with an optimum sea-level pressure of 101.325 kPa (1013.25 mbar, or hPa) or 29.921 inches of mercury (inHg) or 760 millimeters (mmHg).

i'd prefer better than the average 0.9 drag coefficient, and the adhesion coefficient with my front drum brake and rear coasterbrake is 0.85 on dry ground which calculates to a stopping distance of 76.83 feet from 45mph (obviously.)

now, i'm sure my engine would run better if i could lower the drag coefficient, perhaps by half, which would put the drag at 43.118701 Newtons, and my Relative Velocity at 40.5 mph (based on a 0% grade and a 45mph measured velocity,) but unfortunately, my engine can't control the environment it functions in.

to simplify, 75 degrees, sunny and dry, no wind, flat ground, near the beach.

Terry Blow · Dec 13, 2009

At 50cc's or even 80cc's you will never feel the difference period just ride and enjoy forget all the rest Cheer's

Terry :0)

xlite · Dec 13, 2009

"shaved rabbit panther hybrid with a turbine engine attached on ice with a tailwind, driven by an over caffeinated fighter pilot, down a ski jump in Switzerland in better than ideal conditions."

Sparks66 · Dec 13, 2009

bairdco said:
the ideal temperature for my chinee motor is precisely 298.555 degrees Kelvin, with an absolute humidity of 16.6 grams per meter cubed, with an optimum sea-level pressure of 101.325 kPa (1013.25 mbar, or hPa) or 29.921 inches of mercury (inHg) or 760 millimeters (mmHg).

i'd prefer better than the average 0.9 drag coefficient, and the adhesion coefficient with my front drum brake and rear coasterbrake is 0.85 on dry ground which calculates to a stopping distance of 76.83 feet from 45mph (obviously.)

now, i'm sure my engine would run better if i could lower the drag coefficient, perhaps by half, which would put the drag at 43.118701 Newtons, and my Relative Velocity at 40.5 mph (based on a 0% grade and a 45mph measured velocity,) but unfortunately, my engine can't control the environment it functions in.

to simplify, 75 degrees, sunny and dry, no wind, flat ground, near the beach.

Hey thanks. What is your calculated r-square value when determining the coefficient? That would help a lot.
Sparks

Dan · Dec 13, 2009

bairdco said:
the ideal temperature for my chinee motor is precisely 298.555 degrees Kelvin, with an absolute humidity of 16.6 grams per meter cubed, with an optimum sea-level pressure of 101.325 kPa (1013.25 mbar, or hPa) or 29.921 inches of mercury (inHg) or 760 millimeters (mmHg).

i'd prefer better than the average 0.9 drag coefficient, and the adhesion coefficient with my front drum brake and rear coasterbrake is 0.85 on dry ground which calculates to a stopping distance of 76.83 feet from 45mph (obviously.)

now, i'm sure my engine would run better if i could lower the drag coefficient, perhaps by half, which would put the drag at 43.118701 Newtons, and my Relative Velocity at 40.5 mph (based on a 0% grade and a 45mph measured velocity,) but unfortunately, my engine can't control the environment it functions in.

to simplify, 75 degrees, sunny and dry, no wind, flat ground, near the beach.

wut? lol, kidding and am really impressed with the extent of your research. (Now if you could explain some of the larger words to me?)

I would have said a lower temp then 75 for a ChinaGirl, but would have been close to your research.

Was very surprised with the Honda and clones. They are so cleverly cooled that on a cool day, takes forever to get em hot and running optimally. 2 smokers, hot by the time I get to a stop sign in either direction.

Motorbike Wanabe · Dec 13, 2009

Does anyone know the typical temperature of the engine block right after riding? I just installed some small rubber pieces between the fins to see if it actually helps with the engine noise but I was curious if it would hinder the cooling. Right now, it's not very hot here in FL but, it'll get hotter from what I hear.

The hottest temperature that I saw with my temp pointer was 240 degrees. I didn't think that this was too bad, but like I said, it was fairly cool. Just curious if anyone else has an idea on what temp their engine typically runs. I think the rubber actually did help the engine quiet down a little. I'm keeping them in for now.

thanks for any input.

bairdco · Dec 13, 2009

it only took me a few minutes to figure it out in fancy terms. just used online conversions for the kelvin system, a stopping distance calculator from Science of Cycling: Braking & Steering: page 2 and a few random searches to find atmospheric pressure at sea level.

it's also completely biased based on my preference, not my motor. it may run better when it's 50 degrees out, but i'm friggen freezing...

xlite · Dec 14, 2009

Those of use who struggle to get off the ground with 2-strokes that are way underpowered for the wing loading know that the colder it is the better. And it's not just due to increase in lift because we get higher readings during static test too.

It is important to optimize jetting for best performance at a given temp to take advantage.

Norman · Feb 10, 2010

you guys who live near the beach?! Did some of ya ride your bike right off the end of the pier while working the slide rule!!! there some wild high powered ciphering going on there.

Stayed too long in one of the bars by the beach? I stayed too long in one of them bars got a little toasted. But it was fun! You know you've had too many when you think your 10' tall and bullet proof, think you can ride a motorized unicycle.

May I suggest if your freezing or melting riding your bike wait for a day when its not so cold or too hot.
That should be the optimum ambient temperature for the motor and you. dnut

disclaimer: I was Bull pooing all of ya. So don't get upset. Ya hear.

Prasinos · Feb 10, 2010

any chemists want to calculate the amount of water our engines would boil if they were kept at 212 degrees, cause i was thinking about the possibility of having a jug around the engine that would allow water to boil, if i could ride 10 miles on a gallon thatd be cool, obviously a radiatior would be ideal though...

Though this doesn't seem like a great solution, couldn't you also have cold water around your engine keeping everything cool for a high speed run?

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Optimum Ambient Temperature For Motor When Riding

Sparks66

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Venice Motor Bikes

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Terry Blow

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bairdco

a guy who makes cool bikes

Terry Blow

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xlite

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Sparks66

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Dan

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Motorbike Wanabe

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bairdco

a guy who makes cool bikes

xlite

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Norman

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