I don't post often, but i hear a lot of a thick or thin 30w. I realize that a 30 w has a range to fall between to be considered a 30w. I have talked with Mobil, Havoline and Castrol, and they all said the same thing. The oil is measured at 212f for the viscosity. If that temp is 213 or 211, (which i have seen the numbers) a 9.8 cst oil can be 9.8 at 212, but 10.5 at 211. Also, a 12.5 oil can be 9.8 at 213. Plus these numbers they tell you or post on their websites are averages. This doesn't mean you have exactly that vis in you car.
there is no thick of thin 30w
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Thick or thin 30w refers to an oil that, in testing, tends to fall closer to one side of the range on average. For example, if most tests (and the specs) on a 30w are just below a 40w, it would be considered a "thick" 30w.
Originally Posted By: JonS
Chevron is 12.5 at 212. This is an average from them. You could have a 10.0 vis of it in your car right now. All i am saying is that a 30w is (can be) different in every bottle you buy of the same brand, depending on when it was made.
The kinematic viscosity range for a 30wt at 100C is 9.30cSt to 12.49cSt.
You may get a slight difference between batch numbers from an oil company but nothing on the order of magnitude that you're suggesting. For example GC is considered a heavy 30wt with it's KV100 of 12.2cSt. You might get a slight variation of +/- 0.1cSt but that's about it. There are plenty of VOA's you can review in the VOA section that will confirm that.
Chevron is 12.5 at 212. This is an average from them. You could have a 10.0 vis of it in your car right now. All i am saying is that a 30w is (can be) different in every bottle you buy of the same brand, depending on when it was made.
The kinematic viscosity range for a 30wt at 100C is 9.30cSt to 12.49cSt.
You may get a slight difference between batch numbers from an oil company but nothing on the order of magnitude that you're suggesting. For example GC is considered a heavy 30wt with it's KV100 of 12.2cSt. You might get a slight variation of +/- 0.1cSt but that's about it. There are plenty of VOA's you can review in the VOA section that will confirm that.
Now gentlemen, that was great info..........ok.
Chevron 30-weight oils are NOT 12.5cst@100C
They are on the 'thin' side, being 9.7cst@100C.....
If there isn't that much difference between the 'range' of one grade, the WHY do regular oils, between 9.7 and 11.0cst@100 get an 'energy conserving' rating, while HDEO and MH oils, that are usually between 11.0 and 12.4 cst DON'T get this rating???
It means there is a difference between the two.....
They are on the 'thin' side, being 9.7cst@100C.....
If there isn't that much difference between the 'range' of one grade, the WHY do regular oils, between 9.7 and 11.0cst@100 get an 'energy conserving' rating, while HDEO and MH oils, that are usually between 11.0 and 12.4 cst DON'T get this rating???
It means there is a difference between the two.....
Originally Posted By: JonS
The oil is measured at 212f for the viscosity. If that temp is 213 or 211, (which i have seen the numbers) a 9.8 cst oil can be 9.8 at 212, but 10.5 at 211. Also, a 12.5 oil can be 9.8 at 213.
I think you're exaggerating this a bit. Depending on the oil, it should stay within the 9.3-12.49 cSt range for +/- 10 degrees Fahrenheit from 212.
The oil is measured at 212f for the viscosity. If that temp is 213 or 211, (which i have seen the numbers) a 9.8 cst oil can be 9.8 at 212, but 10.5 at 211. Also, a 12.5 oil can be 9.8 at 213.
I think you're exaggerating this a bit. Depending on the oil, it should stay within the 9.3-12.49 cSt range for +/- 10 degrees Fahrenheit from 212.
Originally Posted By: JonS
If that temp is 213 or 211, (which i have seen the numbers) a 9.8 cst oil can be 9.8 at 212, but 10.5 at 211. Also, a 12.5 oil can be 9.8 at 213.
You're really suggesting that a 1 degree F difference in temperature is going to make a nearly >12% difference in viscosity? Seriously??
If that temp is 213 or 211, (which i have seen the numbers) a 9.8 cst oil can be 9.8 at 212, but 10.5 at 211. Also, a 12.5 oil can be 9.8 at 213.
You're really suggesting that a 1 degree F difference in temperature is going to make a nearly >12% difference in viscosity? Seriously??
If anyone wants to see visco at 100C and 99C...
http://www.widman.biz/English/Calculators/Graph.html
http://www.eskoindustries.com/viscadv.php
http://www.widman.biz/English/Calculators/Graph.html
http://www.eskoindustries.com/viscadv.php
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When i had a Jepp 4.0 a few years ago, i was trying to get more oil pressure. The gauge would show 20 psi at idle. I asked Havoline if using a 10w-40 would raise my pressures. He said no, because the thicker oil woul run hotter and be at the same pressure and viscosity as a cooler 10w-30.
Originally Posted By: JonS
When i had a Jepp 4.0 a few years ago, i was trying to get more oil pressure. The gauge would show 20 psi at idle. I asked Havoline if using a 10w-40 would raise my pressures. He said no, because the thicker oil woul run hotter and be at the same pressure and viscosity as a cooler 10w-30.
Thicker oil does run slightly hotter but not anywhere near enough to compensate or offset the increase in viscosity.
One think that may be throwing you is that oil pressure does not correlate well with kinematic viscosity, it does correlate well with HTHS viscosity. In other words, oils with the same HTHS vis will have the same OP regardless of what their KV100 spec's may be.
When i had a Jepp 4.0 a few years ago, i was trying to get more oil pressure. The gauge would show 20 psi at idle. I asked Havoline if using a 10w-40 would raise my pressures. He said no, because the thicker oil woul run hotter and be at the same pressure and viscosity as a cooler 10w-30.
Thicker oil does run slightly hotter but not anywhere near enough to compensate or offset the increase in viscosity.
One think that may be throwing you is that oil pressure does not correlate well with kinematic viscosity, it does correlate well with HTHS viscosity. In other words, oils with the same HTHS vis will have the same OP regardless of what their KV100 spec's may be.
Delo 400 SAE30 viscosity at 100*C is 12.1cSt.
Not to be technical or anything.
Not to be technical or anything.
Using the second link posted by BobFout, gives the following for Mobil 1 5W-30:
99°C(210.2°F) = 11.4cSt
100°C(212°F) = 11.1cSt
101°C(213.8°F) = 10.8cSt
So the viscosity does change with these small changes in temperature, but not as much as the examples in your original post. An oil generally doesn't change a full grade in viscosity until it has dropped a full 10°C(18°F) in temperature.
99°C(210.2°F) = 11.4cSt
100°C(212°F) = 11.1cSt
101°C(213.8°F) = 10.8cSt
So the viscosity does change with these small changes in temperature, but not as much as the examples in your original post. An oil generally doesn't change a full grade in viscosity until it has dropped a full 10°C(18°F) in temperature.
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Originally Posted By: CATERHAM
Originally Posted By: JonS
When i had a Jepp 4.0 a few years ago, i was trying to get more oil pressure. The gauge would show 20 psi at idle. I asked Havoline if using a 10w-40 would raise my pressures. He said no, because the thicker oil woul run hotter and be at the same pressure and viscosity as a cooler 10w-30.
Thicker oil does run slightly hotter but not anywhere near enough to compensate or offset the increase in viscosity.
It is indeed a second-order effect. In my Buick, my last change was from a 10.5 cSt oil to a 12.5 cSt oil (100°C spec). I noticed a 4% increase in oil pressure as well as a slight increase in the heat flux out of the engine (this can be qualitatively inferred from the peak temperature reached between thermostat opening and the cooling system reaching steady-state temperature).
Clearly local temperatures are higher somewhere in the engine, but the amount of extra heat is not enough to lower the viscosity such that the pressure is the same as for a thinner oil.
Originally Posted By: JonS
When i had a Jepp 4.0 a few years ago, i was trying to get more oil pressure. The gauge would show 20 psi at idle. I asked Havoline if using a 10w-40 would raise my pressures. He said no, because the thicker oil woul run hotter and be at the same pressure and viscosity as a cooler 10w-30.
Thicker oil does run slightly hotter but not anywhere near enough to compensate or offset the increase in viscosity.
It is indeed a second-order effect. In my Buick, my last change was from a 10.5 cSt oil to a 12.5 cSt oil (100°C spec). I noticed a 4% increase in oil pressure as well as a slight increase in the heat flux out of the engine (this can be qualitatively inferred from the peak temperature reached between thermostat opening and the cooling system reaching steady-state temperature).
Clearly local temperatures are higher somewhere in the engine, but the amount of extra heat is not enough to lower the viscosity such that the pressure is the same as for a thinner oil.
Originally Posted By: JOD
Originally Posted By: JonS
If that temp is 213 or 211, (which i have seen the numbers) a 9.8 cst oil can be 9.8 at 212, but 10.5 at 211. Also, a 12.5 oil can be 9.8 at 213.
You're really suggesting that a 1 degree F difference in temperature is going to make a nearly >12% difference in viscosity? Seriously??
Yup. Sounding like Dr. Haas and stuff.
And GC is 0W-38, if that helps.
Originally Posted By: JonS
If that temp is 213 or 211, (which i have seen the numbers) a 9.8 cst oil can be 9.8 at 212, but 10.5 at 211. Also, a 12.5 oil can be 9.8 at 213.
You're really suggesting that a 1 degree F difference in temperature is going to make a nearly >12% difference in viscosity? Seriously??
Yup. Sounding like Dr. Haas and stuff.
And GC is 0W-38, if that helps.
Originally Posted By: JonS
if GC measures 12.1 Cst in every bottle, and your engine oil is at 212f, you get a 0w-37.5
OK, I stand corrected. 0W-37.5. Though my original guesstimation and Head Math was pretty good to get 0W-38, proving I am not a computer.
Dr. Haas? Thoughts?
if GC measures 12.1 Cst in every bottle, and your engine oil is at 212f, you get a 0w-37.5
OK, I stand corrected. 0W-37.5. Though my original guesstimation and Head Math was pretty good to get 0W-38, proving I am not a computer.
Dr. Haas? Thoughts?
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