Two valve design for nitrogen purge - exactly how?

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Christos Adam
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Two valve design for nitrogen purge - exactly how?

Post by Christos Adam » Wed Mar 10, 2010 3:35 pm

I read in the info page regarding the 949 wheels:
This makes it possible to perform a complete nitrogen purge. You may notice many high end tires stores now offer nitrogen. Nitrogen doesn't fluctuate pressure as much as your tires get hot and they hold air much longer. With a single valve, you still have some atmosphere in there when inflating with nitrogen. Two valves= 100% nitrogen.

Does anyone know how I'm supposed to do that?
Should I have them filled with nitrogen from one valve and have the second valve partially open releasing the air?
My assumption would be that I should place the Nitrogen valve at the top and the air valve at the bottom - since nitrogen is lighter than air (or more specificaly lighter than O2 and H2O vapors).

Have anyone perform the above process?
Where is the cheapest place to fill my tires up with Nitrogen?
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Re: Two valve design for nitrogen purge - exactly how?

Post by Aaron Goldsmith » Wed Mar 10, 2010 3:40 pm

Christos Adam wrote:I read in the info page regarding the 949 wheels:
This makes it possible to perform a complete nitrogen purge. You may notice many high end tires stores now offer nitrogen. Nitrogen doesn't fluctuate pressure as much as your tires get hot and they hold air much longer. With a single valve, you still have some atmosphere in there when inflating with nitrogen. Two valves= 100% nitrogen.

Does anyone know how I'm supposed to do that?
Should I have them filled with nitrogen from one valve and have the second valve partially open releasing the air?
My assumption would be that I should place the Nitrogen valve at the top and the air valve at the bottom - since nitrogen is lighter than air (or more specificaly lighter than O2 and H2O vapors).

Have anyone perform the above process?
Where is the cheapest place to fill my tires up with Nitrogen?
If you are going to use nitrogen in race tires you need your own tank and accessories. The pressure do still go up, just less.

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Re: Two valve design for nitrogen purge - exactly how?

Post by Jonathan Lugod » Wed Mar 10, 2010 3:46 pm

seeing as the air we breathe is 78% Nitrogen. I personally wouldn't bother with the hassle of Nitrogen in my tires :roll: :thumbup: .

I usually set my starting pressure about a 1.5lb lower on my drive wheels than my target pressure for my first run. :ibrightdea:
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Re: Two valve design for nitrogen purge - exactly how?

Post by Jason Isley BS RX8 » Wed Mar 10, 2010 3:47 pm

That will never get you to 100%. You need a purge system to do it right. At the Natl convention Dan Binks, crew chief for the GM C6Rs, told us they don't even use nitrogen in the tires, they have an air dryer in-line - it is the moister in the air that expands and changes your pressure.

I think dual valves is the suck, they hang up the bead and make it more of a pain to mount some of the difficult/stiff tires.

This is what Kumho was using for their ALMS teams (drilling an extra whole in the wheel is no substitue) http://www.intercomp-racing.com/product ... N=38156864" onclick="window.open(this.href);return false;

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Re: Two valve design for nitrogen purge - exactly how?

Post by Aaron Goldsmith » Wed Mar 10, 2010 4:03 pm

Jason Isley BS RX8 wrote:That will never get you to 100%. You need a purge system to do it right. At the Natl convention Dan Binks, crew chief for the GM C6Rs, told us they don't even use nitrogen in the tires, they have an air dryer in-line - it is the moister in the air that expands and changes your pressure.

I think dual valves is the suck, they hang up the bead and make it more of a pain to mount some of the difficult/stiff tires.

This is what Kumho was using for their ALMS teams (drilling an extra whole in the wheel is no substitue) http://www.intercomp-racing.com/product ... N=38156864" onclick="window.open(this.href);return false;
We've found the major plus of the dual valves to be that you can put your tire gauge on one and fill on the other, works well. Course then I just built a valved filler for our air tank with a pressure gauge so it works that way with one valve wheels. Nitrogen is nice as an easy way to carry a lot of compressed gas without a compressor.

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Re: Two valve design for nitrogen purge - exactly how?

Post by Bill Martin » Fri Mar 12, 2010 11:04 am

This comes up so often. Can anyone point to a link where the benefits of nitrogen are confirmed by test data? The only tests I've seen showed no discernible difference. Yeah, everyone has logical reasons for what they think. Just no supporting data.

edit -- here's one of the testing articles:

http://www.powertank.com/truth.or.hype/" onclick="window.open(this.href);return false;

Note they sell CO2 systems, so perhaps they have an agenda. Testing looked fair to me.

Another test series with identical results (ie, no difference) was published by Eco4, but their site seems to be down.

I've done my own testing, 1) overfill 2 tires nite before, one nitrogen one air. 2) next a.m. bleed to equal pressures. 3) leave in sun for hours and check results periodically. Out here in the desert the tires got too hot to hold your hand on, but never saw difference in pressure build-up. Anybody can do this test -- give it a try.

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Re: Two valve design for nitrogen purge - exactly how?

Post by Mako Koiwai » Fri Mar 12, 2010 9:49 pm

Could be that your desert air was very dry to start with ?

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Re: Two valve design for nitrogen purge - exactly how?

Post by Webster Jessup » Fri Mar 12, 2010 11:13 pm

Nitrogen vs Air?

No discernible difference. The key is keeping the vapor pressure down. Water vapor expands more than dry gas. Even then the pressure rise between humid air and dry air is very small.

HOWEVER
YOU MUST ABSOLUTELY KEEP STANDING WATER OUT OF THE TIRE.

As temperature increases, the water saturation percentage goes up exponentially. The standing water then feeds this system, thus increasing pressure much much more than even humid air. So, be careful when you mount your tires or who you get them mounted by.

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Re: Two valve design for nitrogen purge - exactly how?

Post by Bill Martin » Sat Mar 13, 2010 8:57 am

Mako Koiwai wrote:Could be that your desert air was very dry to start with ?
Yeah maybe. But my compressor tank drains water off the bottom like everybody else's. And it's the compressed air that goes into the tire, not quite the same stuff I breathe. But again...it's a dead simple test. Put a couple of inflated tires out in the sun and see what happens. Need to be off the car and flat on the ground to make sure they get the same sun. My contention is if you can't see a significant difference via your tire gauge, then it won't matter on course. Personally I think it's a scam greatly spread by people with money-making aspirations. But I'm typically a skeptic until I see clear, repeatable data. There are practical reasons for using compressed nitrogen (I carry CO2 to events) but most claims seem to be unfounded. I'd love to see legitimate test data to the contrary. Especially tests that I can reproduce at home.

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Re: Two valve design for nitrogen purge - exactly how?

Post by Bill Martin » Sat Mar 13, 2010 9:02 am

Mako Koiwai wrote:Could be that your desert air was very dry to start with ?
Please disregard my previous post.

EFFECTIVE IMMEDIATELY I WILL BE OFFERING DESERT AIR TOP-UP SERVICE AT EVENTS. FOR A MERE $10 YOU CAN TOP OFF YOUR TIRES FROM MY AIRTANK CONTAINING PURE DESERT AIR. BASED ON MEDIA REPORTS, YOU CAN EXPECT UP TO 5% LOWER LAP TIMES AND UP TO 10% BETTER GAS MILEAGE HEADING HOME. SUPPLIES ARE LIMITED SO GET YOURS EARLY.

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Re: Two valve design for nitrogen purge - exactly how?

Post by Christos Adam » Sat Mar 13, 2010 10:52 am

^ LMAO for the last comment :D :lol:

Anyway the difference in expansion between different types of gas aren't that huge to make a difference (especially when we talk about gases in a 20% of the volume - since 80% is Nitrogen anyways) but there is a difference when a material changes state (from liquid to gas).
I believe that as long as there is no water in the tires from the initial installation (I just remembered that I got a bit crazy with the soapy water during the installation :x on 1/4 tires -then I used Vaseline) I think the differences between Nitrogen filled and air filled tires shouldn't be that great...
The air that we put in the tires is already pressurized in higher pressure and it doesn't have any water in liquid state (even if there is some water in the air tank will stay at the bottom) so if the tires don't have water from installation there should be free from water and therefore similarly "stable" with Nitrogen filled tires.
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