Why does my car have green topped valve covers?
 

Someone at toyota said it was because they put nitrogen in the tires? Wife's car has them too. I think they are ugly. I'm gona get some nice chrome ones

It's to designate that there is nitrogen in the tires. So you or whoever is filling up the tires doesn't mix it with air.

Valve stem cap.

Valve covers = what's over the cylinder head in the engine bay.

-alex

And if they do mix air with it don't panic. It just means you have air mixed with the nitrogen and that has zero effect since air is 78% nitrogen anyway. Nitrogen filled tires are a huge rip off.
Now if they would fill them with helium and make the car lighter.
For god sake do not fill them with hydrogen though.

[OT] Tcoat, I'd like to thank you for your post but being a forum newbie I have no idea how to do it. Is there a button or link I am not noticing. Or is it because newbies are not allowed to thank? Help! ;-) [/OT]

About the only good thing that filling it with nitrogen does, is that it is usually with zero moisture.

This ensures the least amount of tire pressure change as temperatures change.

-alex

I'm not even sure you can see our valve covers in our engine bays :lol:

@mav1178 has it right, nitrogen makes a difference when the tires are at temperature swings, nitrogen doesn't readily get effected by temperatures. In fact nissan made a big deal when the GT-R came out about how they filled the tires with pure nitrogen because normal air was too "unstable". It would probably only ever make a difference in that situation because they are constantly recording data on the nurburgring trying to aim for consistency with variables and such.

Nitrogen is affected exactly like any other noble gas by temperature. It will expand and contract.

H20 molecular bonds in the tire can be broken by temperature changes.
Then the individual 0 and H molecules take up more space than they did before.

Won't matter in the slightest on the road. Track bench racing appellation.

Nitrogen is not a noble gas. But you're right it will expand and contract with temperature changes. Like any gas.

Nitrogen will expand and contract... however, not to the degree of plain old air. So for example during an autocross session, you start when it's cooler out and after a few runs your tires are hot and when you finish later in the day when it's even hotter your tires will go up several PSI. Nitrogen will only go up a few PSI. I'm not good enough to worry about tire pressures yet but all the better drivers are constantly fiddling with theirs

Derp. True.
Tires are still permeable though. Nitrogen leaks out at a slower rate than smaller atoms.
Helium will leak faster. Hydrogen would fall out faster than anything.
Oxygen would leak out slower than Nitrogen, but if you had a bag full of Oxygen in a crash, you may have a bad day.

There is a minimum number of posts before you can thank...IIRC, it's 10.

You do realize I was joking about the other gases? Hydrogen in you tires would be a bad bad bad idea.

Many places made a big deal about it at one time but it has sort of dropped off the map since several government studies showed it is meaningless in a normal car. I am not going to bother to link any because I am perfectly aware there are probably an equal number saying that it is god's gift to tires.
What it is good for is a cheap and easy upsale for dealers and tire places or else it would be gone by now.

Thanks!

PV=NRT
all these gasses act the same in regard to expansion by temperature
the only advantage is that water that has condensed inside the tire may change to vapor at a rate of 22.4 to 1

Bah screw that I'm not paying to fill up on nitrogen. Two tires dont even have caps. They probably all have air anyway

DO NOT use aluminum valve stem caps unless you want to Dremel them off when they seize up on you!

http://i.imgur.com/HHS7Zgmm.png

Skeptical Dog says he would like to learn more about this miracle of chemistry.

Me too.......:confused0068:

YIKES, does that mean that the old air in my tires contains free hydrogen ... ??

What if it ignites, will my tires blow up ..... :eyebulge:

When I let air out of my tires, should I not have an open flame in the area ... ??

Should I put fresh air in my tires every now & then .. ??

:sigh:


humfrz

We could fill the tires with water and run the engine with the hydrogen and oxygen.

YES!

All we need is a heat source to start the thermal decomposition of the water molecules. Let's see, I wonder if the heat off of a turbocharger would reach up to 1,000 degrees C to get it started ..... :iono:

We just may be onto something BIG here ...... :cheers:


humfrz

Oh wow! You are a GENIUS! Now don't tell a soul. We don't want anyone to steal our ide...



...shit.

No no no.... youre doing that wrong. You need to use power from the alternator to dissociate water into H & O2, then feed that into the engine , recombust it, and make more power.
No really it works...... saw it on an info-mercial - they cant lie....

And as for the Air vs Pure nitrogen:
The ONLY benefit it gives you is lack of moisture.

The difference between pure Nitrogen and and a Blend of Nitrogen 78% and Oxygen 21% (Air) is in the noise.
Nitrogen & Oxygen are right next to each other on the periodic table.
(Atomic Mass only differs by ~10%)

Not to worry, they don't know about our secret catalyst :thumbup:


humfrz

Well, justatroll, electrolysis of water would produce hydrogen ....... but that's soooo old school (must have been an old info-mercial).

We are waaaaay far advanced from that ..... :happyanim:


humfrz

Oh, BTW, we can't discover any more elements ...... because the bottom row of the periodic table is all filled up .........:thumbsup:

Nitrogen is the only thing filled in commercial aircraft tires for a reason......yes its better i.e.......less effected by heat and cold cycling pressure changes....less abnormal tire wear....yes its the only thing I would put in my tires if I had the choice.....thats the catch though.....1...im not going to be seeking a dealership anytime I want tires serviced....2 Im not going to buy/rent bottles.....so pure air it is....

[ame="http://www.amazon.com/Mini-Inline-Desiccant-Dryer-Filter/dp/B00W7XHT52"]Amazon.com: 1/4" Mini Inline Desiccant Air Dryer / Filter 2 Pack (Made in USA): Automotive[/ame]

Costco uses nitrogen to fill the tires they sell. Free fill to if your a member.

Sent from my SM-T530NU using Tapatalk

Today I learned that I can separate water into H2 and O molecules just by doing burnouts.

/sarcasm

They are also aircraft. If anybody here is stressing their tires to the level of aircraft take off and landing and consistently driving at temperatures as low as they are at altitude then I would love to see the build. There is zero advantage to nitrogen filled tires in your normal street driven car. This has been proven time and time again.

Trying to imagine an FRS that weighs 100 tons and makes an abrupt stop from 170 mph to 0.

Or hits 300MPH for a 1/4 mile or so and then suddenly removes that pressure.
Be quite the car.

The green valve stem caps are put on there to let service personnel know that you are gullible enough to pay for such a scam. Or at least set up for the "Conversation" that you must maintain your tires with pure nitrogen so that they can relieve you of more $$$.

God help you if you should ever get some "Air" mixed in with your Nitrogen!

Someone needs to make the agnostic version of this cap.

Totaled

I am seeing nitrogen filled tires as an add-on line item at many car dealers, including my Subaru dealer. They didn't have that when I bought my BRZ from them late 2013.

Refuse to pay it.

So many places do it for free it's not automatically a marker for an idiot.

Have heard stories about foolish service people refusing to air up a customers tires because they are green capped and they don't have nitrogen and it would be dangerous to mix the two.

They do, it's a black plastic one, and they're way lighter than the fancy little metallic ones.

Definitely not worth paying any money for it.

I wonder if there is free hydrogen in my farts?

Science says there is. http://gut.bmj.com/content/32/6/665.long