Nitrogen in your tires!
04-07-2007, 03:41 PM
#46
Rennlist Member
So, if there is no "molecular bond", as you are right air is made up of Co2 from us and other things, o2 from plants and nitrogen from where ever, and its all a big air stew. great. Then the point would be is it likely that a leak from a tire is just the perfect size to filter out the o2 molecules only? if you got a leak, its going to leak the air (made up of both the o2 and the Nitrogen.) it would be a long shot to think that the leak was just the perfect size to leak only the o2 and not the nitrogen, based on molecule size.
now, im wondering about NOS. if you you do have a masters in Chem, is there a difference with No2? could those molecules be larger?
an observation. it seems all my kids toys filled with NOS seem to leak. even got a new innertube for the kids bike and it still leaks. havent tried air yet, but thats next. my race tires dont leak though. (hoosiers did, due to the porus rubber from what ive been told)
Mk
now, im wondering about NOS. if you you do have a masters in Chem, is there a difference with No2? could those molecules be larger?
an observation. it seems all my kids toys filled with NOS seem to leak. even got a new innertube for the kids bike and it still leaks. havent tried air yet, but thats next. my race tires dont leak though. (hoosiers did, due to the porus rubber from what ive been told)
Mk
Originally Posted by Larry928GTS
Sometimes, but a lot of times common sense seems to be even more rare than "air molecules", and those molecular bonds that you have to break to separate the oxygen from them.
04-07-2007, 04:18 PM
#47
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Originally Posted by mark kibort
why would you care unless you are racing? even racing, its tough to get all the old air out. starting with a flat tire, you get only 2/3s Nitrogen. all for what? trying to reduce the pressure rise for a hot tire?
mK
mK
Great answer and true!
Thanks Mark!
04-07-2007, 07:20 PM
#48
Air is a mixture of the different gasses. There are no bonds holding the molecules of the different gasses that the air consists of together, and there's no such thing as air molecules. Air is basically like squirting nitrogen and oxygen into a container. The rubber of the tire is porous enough that both the oxygen and nitrogen gas molecules can get through it, but since the oxygen molecules are smaller they can get through easier and faster than the nitrogen molecules can.
Nitrous is not just a mixture of gasses like the air is, but rather consists of nitrogen atoms and oxygen atoms that have a bond holding them together to form a nitrous oxide molecule. Nitrous oxide does not burn, and does not increase combustion of anything that is burning. The bonds that hold the nitrogen and oxygen together aren't really that strong, and break when the nitrous oxide molecules are heated to somewhere in the 500-600 degrees F range. When those bonds are broken, the nitrous oxide breaks down into a mixture of nitrogen and oxygen. The separated oxygen that now exists won't burn by itself either, but will definitely contribute to increased burning of anything there that is burning already, or that will burn if ignited. Air is about 78% nitrogen and 21% oxygen. Nitrous is 64% nitrogen and 36% oxygen. That means when the nitrous oxide breaks down into the nitrogen and oxygen, there's a good bit more oxygen available for the burning process than if it were just the oxygen from air present. That's why injecting nitrous gives more power than if you were to inject just air in the same way. When you inject nitrous into an engine you're displacing some of the air that's only 21% oxygen with nitrous that's 36% oxygen. If you displaced all of the air going into the engine with 100% oxygen, you'd get even more power than with nitrous, at least until things melted and/or blew up. I wouldn't expect that to take to long at all.
If you have a tire that you've just mounted to a rim, it has only atmospheric pressure air in it. That would be around 14.7psi absolute pressure, and zero psi pressure on your tire gauge. Fill the tire with nitrogen until you've got 29.4psi pressure showing on your gauge and you've now got 29.4psi gauge pressure and 44.1psi absolute pressure in the tire. What's now in the tire is roughly 66% nitrogen that you used to inflate the tire with, and 33% air that was in there from before you inflated it. That air consists of roughly 78% nitrogen. Take 78% of the 33% air, and you get 25.7% of the gas inside the inflated tire being nitrogen from the air that was in the tire before you inflated it. Add that 25.7% to the 66% of the gas in the tire that's the nitrogen you added when you inflated it, and you end up with a total of 91.7% nitrogen in the inflated tire.
Would I spend anything extra to put nitrogen in a street car's tires? No.
Nitrous is not just a mixture of gasses like the air is, but rather consists of nitrogen atoms and oxygen atoms that have a bond holding them together to form a nitrous oxide molecule. Nitrous oxide does not burn, and does not increase combustion of anything that is burning. The bonds that hold the nitrogen and oxygen together aren't really that strong, and break when the nitrous oxide molecules are heated to somewhere in the 500-600 degrees F range. When those bonds are broken, the nitrous oxide breaks down into a mixture of nitrogen and oxygen. The separated oxygen that now exists won't burn by itself either, but will definitely contribute to increased burning of anything there that is burning already, or that will burn if ignited. Air is about 78% nitrogen and 21% oxygen. Nitrous is 64% nitrogen and 36% oxygen. That means when the nitrous oxide breaks down into the nitrogen and oxygen, there's a good bit more oxygen available for the burning process than if it were just the oxygen from air present. That's why injecting nitrous gives more power than if you were to inject just air in the same way. When you inject nitrous into an engine you're displacing some of the air that's only 21% oxygen with nitrous that's 36% oxygen. If you displaced all of the air going into the engine with 100% oxygen, you'd get even more power than with nitrous, at least until things melted and/or blew up. I wouldn't expect that to take to long at all.
If you have a tire that you've just mounted to a rim, it has only atmospheric pressure air in it. That would be around 14.7psi absolute pressure, and zero psi pressure on your tire gauge. Fill the tire with nitrogen until you've got 29.4psi pressure showing on your gauge and you've now got 29.4psi gauge pressure and 44.1psi absolute pressure in the tire. What's now in the tire is roughly 66% nitrogen that you used to inflate the tire with, and 33% air that was in there from before you inflated it. That air consists of roughly 78% nitrogen. Take 78% of the 33% air, and you get 25.7% of the gas inside the inflated tire being nitrogen from the air that was in the tire before you inflated it. Add that 25.7% to the 66% of the gas in the tire that's the nitrogen you added when you inflated it, and you end up with a total of 91.7% nitrogen in the inflated tire.
Would I spend anything extra to put nitrogen in a street car's tires? No.
04-07-2007, 08:00 PM
#49
Rennlist Member
So, thanks for the chem lesson! and it sounds like we have broken it down pretty well. so, you end up with 92% nitrogen on a tire fill up. Then, the question is if you live in texas like the guy from a shop on this thread who puts nitrogen in "all his customers tires" what is the moisture level if that 8% air still left in the tire, was drawn from 100% humidity air?
I have to imagine you could be getting close to the air that i use in california on a dry 10% humidity day.
another data point. when racing at Road america on a near 95% humdity day, 90 degrees outside, i didnt notice any unusual pressure rises in my tires for similar tire temps after the practices or races. Again, like you, i would never go through the trouble of using Nitrogen, even in my racing activities. i can achieve the pressures i need by expecting the pressure rise with my use of partially dry NOS or just the air from the tire guy. If it was so special, i think more of the world challenge pro teams would be using nitrogen, as only a few of the ones i saw did. Anderson did it during our last World challenge race, and i dont think he saw anything to write home about. imagine the effects on a street car?????
mk
I have to imagine you could be getting close to the air that i use in california on a dry 10% humidity day.
another data point. when racing at Road america on a near 95% humdity day, 90 degrees outside, i didnt notice any unusual pressure rises in my tires for similar tire temps after the practices or races. Again, like you, i would never go through the trouble of using Nitrogen, even in my racing activities. i can achieve the pressures i need by expecting the pressure rise with my use of partially dry NOS or just the air from the tire guy. If it was so special, i think more of the world challenge pro teams would be using nitrogen, as only a few of the ones i saw did. Anderson did it during our last World challenge race, and i dont think he saw anything to write home about. imagine the effects on a street car?????
mk
Originally Posted by Larry928GTS
Air is a mixture of the different gasses.
Nitrous is not just a mixture of gasses like the air is,
and you end up with a total of 91.7% nitrogen in the inflated tire.
Would I spend anything extra to put nitrogen in a street car's tires? No.
Nitrous is not just a mixture of gasses like the air is,
and you end up with a total of 91.7% nitrogen in the inflated tire.
Would I spend anything extra to put nitrogen in a street car's tires? No.
04-07-2007, 09:35 PM
#51
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Originally Posted by Bill Ball
I use 80% nitrogen. You can get it almost anywhere. 
