| ewissam |
Hi Members ,
As you may be aware of, now most of the tires are inflated using Nitrogen instead of normal Air.
I am following 36-38 PSI for normal air as per Honda ( Max is cold 40 PSI)
Any Idea what will be the PSI when using Nitrogen instead of normal Air ?
For inforamtion about Nitrogen benefits please read :
http://www.stonetires.com/nitrogen.htm
Appreciate your feedbacks
Thanks
Wissam
Kuwait |
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| nonothing |
ewissam
The pressure is the same just put in the same pressure that you normally like to run and thats it. The benefit of running N2 is the fact that it is not effected by heat as much as regular air therefore there is less fluctuation in your tire pressure. N2 has lower expansion and contraction coefficients thats why nascar and other racing leagues use it to keep the handling of the car more consistant because really your tire is just a spring that also stick you to the road so you want to keep the spring rate consistant so crew chiefs can adjust the car by changing N2 tire pressure. |
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| N_Jay |
quote:
Originally posted by nonothing
. . .N2 has lower expansion and contraction coefficients . .
WOW!!!!!!!
They repealed Boyle's Law?
What next, will the Tornado help us break the laws of thermodynamics? |
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| N_Jay |
The pressure should be exactly the same as you like to use for normal air inflation.
The less expansion is due to being a dry gas.
The less pressure loss is due to being non-oxidising so it is not consumed by oxidation of the tire or wheel.
Racers use it because it is about the easiest and cheapest non-oxidising, non-flammable, dry gas commercially available.
While pneumatic tires do have a spring like effect, the pressure is not adjusted to adjust the spring rate. It is adjusted to adjust the contact patch area, and the distortion of the contact patch under dynamic loads of cornering.
If you get nitrogen inflation, I would;
Get the tires inflated, (to anywhere between desired and max PSI)
Run them till hot, (To evaporate as much moisture as possible from inside the tire)
Bleed off the pressure till flat, (removing as much of the "wet" air/N2 mixture as practical)
Refill to well above desired pressure (but below the tire max),
Then bleed then down to the desired pressure when cold. |
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| nonothing |
quote:
Originally posted by N_Jay
WOW!!!!!!!
They repealed Boyle's Law?
First off what you had to say about contact patch is correct but your comment about the not adjusting the air pressure to adjust spring rate is wrong many times the best crew chiefs in the world have said that adjusting air pressures changes the spring rate of the car which in turn helps with the contact patch of the tire.
I think I answered ewissam question in my first sentence and I just gave another reason for using N2 I didn't feel the need to sound smart but I see you went away for 10 minutes to do an internet search for an answer that sounded smarter than mine. But you should have taken a little more time to research.
Boyle's Law gives the relationship between pressure and volume if temperature and amount are held constant. I don't know what planet you are from N_Jay but here on earth the temperature fluctuates and when we drive here on earth the tires tend to heat up therefore Boyle's Law does not apply in this case because temperature changes. If you are going to quote a law to make fun of others trying to help out you should read the laws and try to understand them first cause I do since I'm a chemical engineer. I didn't think it was necessary to go into that much detail but here you go pay close attention to number 4.
The kinetic theory of gases, Graham's law of effusion and root mean square velocity all explain how individual molecules in a gas act and their relation to pressure, volume, and temperature. Dalton's law of partial pressures, another important gas law, explains the behavior of mixtures of gases.
This law has the following important consequences:
1. If temperature and pressure are kept constant, then the volume of the gas is directly proportional to the number of molecules of gas.
2. If the temperature and volume remain constant, then the pressure of the gas changes is directly proportional to the number of molecules of gas present.
3. If the number of gas molecules and the temperature remain constant, then the pressure is inversely proportional to the volume.
4. If the temperature changes and the number of gas molecules are kept constant, then either pressure or volume (or both) will change in the direct proportion to the temperature.
You are also wrong about the fact that it is used cause it is dry if that were the fact then they would simply use bone dry air as it is called in industry and it is cheaper than N2. Once again the reason they use it is because N2 does not expand as much as air when heated as well as the fact that it is a noble gas and therefore it is very unreactive and it contains no O2 which cause oxidation or the breakdown of the rubber.
This site is great and snide comments like yours (which are frequent) just tarnish a good thing. |
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| N_Jay |
quote:
Originally posted by nonothing
First off what you had to say about contact patch is correct but your comment about the not adjusting the air pressure to adjust spring rate is wrong many times the best crew chiefs in the world have said that adjusting air pressures changes the spring rate of the car which in turn helps with the contact patch of the tire.
Can you find me a reference. All my racing friends adjust tire pressure based on the temperature measurements across the tread. This would be directly related to the amount of heating of the tread due to flexing of the tire and not the "spring rate" of the tire.
No one is going to compromise tire grip in the corners just to get a little better "spring rate" over a bump or two.
quote:
Originally posted by nonothing
I think I answered ewissam question in my first sentence and I just gave another reason for using N2 I didn't feel the need to sound smart but I see you went away for 10 minutes to do an internet search for an answer that sounded smarter than mine. But you should have taken a little more time to research.
Why do you assume I"went away for 10 minutes to do an Internet search"? Had I, I would have realized I was misusing Boyle's Law, and should have be quoting the "Ideal Gas Law". Sorry for the mistake. Chemistry was almost 30 years ago.
Yes, you answered the question, then added an almost irrelevant factoid.
quote:
Originally posted by nonothing
Boyle's Law gives the relationship between pressure and volume if temperature and amount are held constant. I don't know what planet you are from N_Jay but here on earth the temperature fluctuates and when we drive here on earth the tires tend to heat up therefore Boyle's Law does not apply in this case because temperature changes.
My mistaken memory of Boyle's Law, was that it also stated that given a fixed volume and mass, changes in pressure are linear with temperature.
Somewhere along the way, I came to the understanding that most dry gasses at or near standard temperatures and pressures followed the gas constant for expansion.
If this is mistaken belief, please point me in the right direction.
quote:
Originally posted by nonothing
If you are going to quote a law to make fun of others trying to help out you should read the laws and try to understand them first cause I do since I'm a chemical engineer. I didn't think it was necessary to go into that much detail but here you go pay close attention to number 4.
The kinetic theory of gases, Graham's law of effusion and root mean square velocity all explain how individual molecules in a gas act and their relation to pressure, volume, and temperature. Dalton's law of partial pressures, another important gas law, explains the behavior of mixtures of gases.
This law has the following important consequences:
1. If temperature and pressure are kept constant, then the volume of the gas is directly proportional to the number of molecules of gas.
2. If the temperature and volume remain constant, then the pressure of the gas changes is directly proportional to the number of molecules of gas present.
3. If the number of gas molecules and the temperature remain constant, then the pressure is inversely proportional to the volume.
4. If the temperature changes and the number of gas molecules are kept constant, then either pressure or volume (or both) will change in the direct proportion to the temperature.
Thanks,
I get all that (and only was mistaken on the name of the law, Boyle's being one specific case of the Ideal Gas Law)
So now can you point me to a table or equation that shows how to apply different coefficients of expansion of various gasses to the facts you pointed out.
quote:
Originally posted by nonothing
You are also wrong about the fact that it is used cause it is dry if that were the fact then they would simply use bone dry air as it is called in industry and it is cheaper than N2.
That would take care of one of the reasons I provided, but if you read my ENTIRE POST (as I did yours) you would see that "Bone Dry Air" would not meet all the goals.
quote:
Originally posted by nonothing
Once again the reason they use it is because N2 does not expand as much as air when heated
If you say so, but I would like a definitive reference (to help me correct my misunderstanding).
quote:
Originally posted by nonothing
. . as well as the fact that it is a noble gas and therefore it is very unreactive and it contains no O2 which cause oxidation or the breakdown of the rubber.
Yes, as I said, but you said in a much more "noble" manner (Pun intended).
quote:
Originally posted by nonothing
This site is great and snide comments like yours (which are frequent) just tarnish a good thing.
To quote the signature line a friend uses "Lighten up Francis" |
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| ewissam |
Thanks N_Jay for the useful information..I appreciate
Ewissam |
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