Originally Posted by serialk11r (Post 46691)

Only at very high pressure (10-hundreds of atm) do gases exhibit noticably different behavior. I thought the benefit of nitrogen was the lack of moisture and oxygen which reduces oxidation on the tire?

Originally Posted by WingsofWar (Post 46703)

When i did the whole nitrogen air thing, i was just taken in by Nissans marketing ploy at Nitrogen gives performance. And since i knew lots of the techs that worked at the local dealership at the time of the GT-R launch i was able to fill my tires with nitrogen for free a few times.

Snake oil? all in my head? most probably...but since it makes me happy and i swear it feels different on the road, especially when its really cold. I'll continue to do it.

Originally Posted by tranzformer (Post 46704)

Just curious what the cost is for a fillup if you don't know someone?

Originally Posted by WingsofWar (Post 46705)

retarded expensive...last i heard it was like $10 for all 4 tires. But you might find cheaper places, nitrogen fillup stations might be found somewhere close to you, but they arn't common yet.

Originally Posted by WingsofWar (Post 46705)

retarded expensive...last i heard it was like $10 for all 4 tires. But you might find cheaper places, nitrogen fillup stations might be found somewhere close to you, but they arn't common yet.

Originally Posted by RRnold (Post 46676)

Nitrogen in tires sounds like a highly debatable topic! :popcorn:

From a motorcycle perspective, tires are the most crucial piece, espeically when we're on the track. If we're running race d.o.t or slicks in either medium, soft and hard compounds, we have monitor them very closely or else we'll be sliding on our ass.

We have to check the psi @ cold tire temp and also when they are up to temp. We also have to make sure we have the correct psi per the manufacture's specs for both temps. We also have to monitor the heat cycles so most riders will use tire warmers to help keep the tire temp from fluctuating while in the pits.

I've never used nitrogen, just the regular gas air pump or compressor. Is it free and only at specific shops? Have you guys even noticed a difference?

Originally Posted by WingsofWar (Post 46664)

Many of those makers will require the ECU to be shipped out and have a daughterboard installed at a price where stand alones could be had. Todays ECUs can be cracked, but the Subarus ECUs have a hardware/software that has active learning that cannot be deleted. Which makes factory ECU remaping difficult.

COBB access port reflashes ECUs for on-demand preset maps, but if your unfamiliar with Subaru ECUs this becomes especially moot because of active learning. Any aggressive ECU maps for N/As do not exist for this reason as they become deleted after a short drive and revert back to OEM maps.

Flywheels are probably the best mod iv ever done on a street car (5 of my cars had lightweight flywheels). There is usually 2 weights available for anycar, one is a street oriented flywheel that can weigh anywhere from 11-15lbs vs a 25lbs steel flywheel. And a race oriented FW thats 7-10lbs. Many people make the mistake to get the lightest flywheel, which makes it completely unstreetable. Your RPMs climb with ease and making your engine feel more free and happy especially at powerband. The difference happens during decel, your RPMS will drop so quick you can stall the car even running at high speed. Street FW dont usually see this problem across makers, but its something to be concerned about.

Originally Posted by PAImportTuner (Post 46774)

Daughterboards are cheap and you can install them yourself with $80 worth of tools, consumables and some patience. I used to solder/install chips/boards/dataloggin ports onto Honda ECUs, also have built a couple PNP Megasquirt EMS for people.

Never heard of the COBB vs Subaru ECU active learning thing but my friends or I never had issues. Maybe because COBB does base mapping and real-time mapping. If you do real-time the system acts as a piggyback it does not flash the memory on the ecu like base mapping does.

COBB AP, UTEC and other piggybacks will keep the tune active, overriding the factory parameters. AEMs new FIC is the same thing. Plus I would not want a stand-alone been there done that $1200ea x2. When the thing dies or having issues for whatever reason I would like to still be able to get home on the stock ecu.

Also I ran all my Hondas with race flywheels no problem. As long as you are a good responsive driver you should be able to drive like almost stock. I always used a 6-puck unsprung clutch too, causing chatter sometimes. Never did I stall and I could parallel park with ease in the city, but again I'm not a normal driver.

Originally Posted by Maxim (Post 46748)

There's some misunderstanding about the application and purpose of nitrogen in tires.

It's not a weight savings aid. The difference in weight on a low profile tire would be measured in single digit grams.

The nitrogen molecule is significantly larger than the oxygen molecule. Nitrogen filled tires generally stay at the exact same PSI for the life of the tire. I have had 4 tires filled with nitrogen on my car for over 15,000 miles, they've been through 2 winters, sat for a month and a half while I was in the field, and various other things that are bad for tires. I have not had to add any air to the tires once. The nitrogen simply doesn't leak out of the stem valve like oxygen does over time.

The tire will also deflate markedly slower if there is a leak, like a nail puncture.

There are no performance benefits to using nitrogen, however the fact that your tires will no longer slowly deflate over time, even when sitting or during extreme temperature conditions, is more than worth the $10 or so it costs to do it.

Originally Posted by serialk11r (Post 46808)

Actually that's not true at all. N2 has a shorter bond length due to its triple bond, and therefore has a smaller molecular "size". N2 is also lighter than O2 by 12.5% so if anything, N2 diffuses faster. Air is 78% nitrogen anyways. The only reason to use nitrogen is to slow oxidation, which is why they use them in airplane tires which are at much higher pressure. How much of a benefit reduced oxidation is, I don't know, but pick up a Chemistry textbook and you'll see why it doesn't really make a difference. Same pressure, volume, temperature = same molar mass. At low pressures most gases have approximately the same specific heat capacity, so the temperature fluctuation argument is BS.

Originally Posted by Maxim (Post 46809)

Explain why my tires have stayed at the same PSI without a single leak for 15k then....if it's not the molecule size it must be something.

Originally Posted by Maxim (Post 46809)

Explain why my tires have stayed at the same PSI without a single leak for 15k then....if it's not the molecule size it must be something.

Originally Posted by Maxim (Post 46809)

Explain why my tires have stayed at the same PSI without a single leak for 15k then....if it's not the molecule size it must be something.