Why does my car have green topped valve covers? - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

RichardsFRS · 01-12-2016, 08:34 PM

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

TruRace · 01-12-2016, 08:40 PM

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.

mav1178 · 01-12-2016, 08:41 PM

Valve stem cap.

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

-alex

Tcoat · 01-12-2016, 08:49 PM

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.

mdm · 01-12-2016, 08:52 PM

[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]

mav1178 · 01-12-2016, 08:54 PM

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

FRSBRZGT86FAN · 01-12-2016, 08:56 PM

Quote:

Originally Posted by mav1178

Valve stem cap.

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

-alex

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

FRSBRZGT86FAN · 01-12-2016, 09:03 PM

Quote:

Originally Posted by mav1178

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

Quote:

Originally Posted by Tcoat

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.

@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.

bcj · 01-12-2016, 09:14 PM

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.

mdm · 01-12-2016, 09:17 PM

Quote:

Originally Posted by bcj

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

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

Ashikabi · 01-12-2016, 09:24 PM

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

bcj · 01-12-2016, 09:26 PM

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.

roddy · 01-12-2016, 09:29 PM

Quote:

Originally Posted by mdm

[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]

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

Tcoat · 01-12-2016, 09:33 PM

Quote:

Originally Posted by bcj

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.

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

01-12-2016, 08:34 PM	#1
RichardsFRS Senior Member Join Date: Dec 2015 Drives: 2013 Pearl White 6MT Location: Gainesville Ga Posts: 938 Thanks: 5 Thanked 356 Times in 246 Posts Mentioned: 13 Post(s) Tagged: 2 Thread(s)	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

01-12-2016, 08:49 PM	#4
Tcoat Senior Member Join Date: Jul 2014 Drives: 2020 Hakone Location: London, Ont Posts: 69,841 Thanks: 61,656 Thanked 108,295 Times in 46,456 Posts Mentioned: 2499 Post(s) Tagged: 50 Thread(s)	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. __________________ Racecar spelled backwards is Racecar, because Racecar.

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01-12-2016, 08:40 PM	#2
TruRace Senior Member Join Date: Sep 2013 Drives: FRS-Raven-MT Location: Ft. Lauderdale, FL Posts: 336 Thanks: 58 Thanked 143 Times in 99 Posts Mentioned: 5 Post(s) Tagged: 2 Thread(s)	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.

01-12-2016, 08:41 PM	#3
mav1178 Senior Member Join Date: Apr 2013 Drives: 2005 Toyota Camry Location: 91745 Posts: 6,562 Thanks: 493 Thanked 6,099 Times in 3,030 Posts Mentioned: 95 Post(s) Tagged: 3 Thread(s)	Valve stem cap. Valve covers = what's over the cylinder head in the engine bay. -alex

01-12-2016, 08:52 PM	#5
mdm not a twin owner Join Date: Jan 2016 Drives: 2016 Veloster Turbo DCT Location: Northern Virginia, USA Posts: 734 Thanks: 992 Thanked 463 Times in 267 Posts Mentioned: 7 Post(s) Tagged: 2 Thread(s)	[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]

01-12-2016, 08:54 PM	#6
mav1178 Senior Member Join Date: Apr 2013 Drives: 2005 Toyota Camry Location: 91745 Posts: 6,562 Thanks: 493 Thanked 6,099 Times in 3,030 Posts Mentioned: 95 Post(s) Tagged: 3 Thread(s)	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

01-12-2016, 09:24 PM	#11
Ashikabi Senior Member Join Date: Aug 2014 Drives: 2013 FR-S Location: Northwest Iowa Posts: 7,359 Thanks: 454 Thanked 4,549 Times in 2,950 Posts Mentioned: 59 Post(s) Tagged: 5 Thread(s)	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

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