TmillerC5

Any advantages?

Got track tires mounted and the guy was pushing the nitrogen. It made some sense, but thought I would pose the question here.

What pressure would you run if you were to use it.
I am running Hoosier R6's

TIA
Tim

Aardwolf

I've seen some huge threads on this. I just use my air compressor at home with a water filter on it, normal air has enough nitrogen for me.

robvuk

78%

yellow01

Yep, I put nitrogen in all my tires

Yellow73SB

Plus oxygen, and many other gases

0Randy@DRM

The bottles of gas are much more pure and should be used in race cars. But for the average hpde and stuff like that it isn't as important. Just make sure you use good compressed air, which means drain the water out of the tank.

Randy

davidfarmer

simply builds less pressure due to less moisture. You need to drain and refill you tires MANY times to get all of the moisture out, that was used during mounting.

A good dry air source is just as good, although I did use Nitrogen in my racing days. Made cold pressures and hot pressure slightly closer to each other (tires ready to go sooner) and more predictable.

69427

Guys, I have two serious questions. And serious answers only, please. The consensus seems to be that nitrogen or dry air are the preferred tire inflation gasses, but is humidity in the air source really a negative thing? According to my old CRC book, nitrogen has a specific heat of .249 cal/g-K, while water vapor has a specific heat of about .480 at the temperatures and pressures seen in a tire under racing conditions. It would seem that the water vapor in the tire would soak up heat better than dry air/nitrogen, resulting in a lower pressure rise in the tire during transient loading (ie: cornering). Under constant skid pad use, the tire would eventually stabilize at some constant temperature, so it might be a non-issue there. I don't know.
Now, the other side of the coin, of which I can't find the data yet, is: What would be the pressure increase due to water vapor temperature rise (compared to nitrogen temperature/pressure rise) as it is heated up to internal tire temperatures (a couple hundred degrees F)? Chemistry class was quite a few years ago, so I'm a bit rusty here. If someone can point me to the correct information here I would greatly appreciate it.

thanks,
Mike

db2xpert

We'll see over the next two days at Pocono. I normally see a 6-8# increase in tire pressures from the cold srating pressure to the pressure
when I come off the track. Just filled with nitrogen today, and I'll see how much the gain is tomorrow. If it cuts the gain to 4# or less, I'll be happy.

Joel

danswofford

I've got a tank of 100% Argon for my MIG welder, I wonder if that would work in lieu of Nitrogen?

ghoffman

The reason I use N2 is I had to have it for the Penske shocks anyway and tanks are cheap. I put it on a small dolly with a yellow coil hose and and it is easier to take a tank to the track than a compressor and generator. I am not sure about the specific heat (good) question, but I know someone who I can get the answer from. As far as the Argon goes, I was going to do that since I had that as well, but I could not get a 0-200 PSI regulator for the Ar bottle, otherwise it would work well, although it is more expensive than N2.

ZR1 MK

Also consider the water in the lube the tire mounter uses. Plus, if you dont vac all ambient air out, your down on purity. I have been mounting my own tires dry for years now. No water, no goo build-up and they dont slip on the wheels.

danswofford

I've always wondered why road racers don't use pressure bleed-off valve stems like the circle track guys do. With them you just inflate the tires and the valves bleed off excess pressure as they warm up. Bingo you always have the correct pressure regardless of temperature, well unless the tire gets cold during a yellow.

AZ FASTEST

I get my tires filled with nitrogen here in Phoenix from the NitrogenMan: http://www.nitrogenman.com/

There is all the info you'll ever want on nitrogen for tires at the following site: www.getnitrogen.org

LG Motorsports

Guys,

It is all about consistency. The humidity is different at every track, and so when the tire guys mount the tires, they ambient air is what is in the tires.

We have a very consistant method of bleeding the air out of the tires, to get rid of the regular air and put Nitrogen in them and let them bleed down again and again 4 times.

Would 5 be better? maybe but as long as we are consistant at each track we get rid of almost all of the abmient air and moisture.

This give us a base line so we can set our "super secret" tire pressures at each event with confidence knowing that the expansion will be exactly what we expect and it will not change as long as we don't put normal air into the tire again.

the tire does not know "What" is in the tire, all it knows is PSI and that is what a racer wants to have control of.

Bleeders are good but they require maintainence and they are not legal in the World Challenge series.

Just get a handle on what PSI you want when the tires are hot and what they will be during the race when they are up to Full Temp.

Don't leave such an important part of your performance equation to chance. And Nitrogen reduces how much the PSI in your tires will vary.

Thanks
Lou Gigliotti
LGM

varkwso

Water and water vapor are amazingly simple and complicated. Conversion of water to steam and its expansion (and contraction) due to temperature are the issue and it is a well documented issue (check the ASME boiler code for one). It really has to do with the partial pressures of a "wet" mixed gas. A "wet" vapor expands at an exponential rate compared to a "dry" gas based on pressure and temp. Nitrogen is used since it is inert and relatively cheap.

Specific heat for liquid water 1.0 (liquid - the baseline for the graph!)

solid 0.5 (ice)
gas 0.47 (gas)

Water vapor is somewhere between .47 and 1.0 dependent on pressure and temp...plus the gas mixture.

Once heated it takes a long time for water to cool off but it can, and does, result in larger pressure differentials in mixed gases - boiler code can help you here..


jeff