Cold weather viscosity

[Patman]

A little while back there was a post on here which showed the viscosity of various oils at various temperatures, including GC and Mobil 1, and it showed what the viscosity of these oils were at various temps (like at 20C, 10C, 0C, etc) I'm curious as to how these viscosities were determined? (since the manufacturers don't publish the viscosity at any other number other than 40c and 100c)

I'd like to see a comparison between GC 0w30 and PP 5w30 for instance, as well as seeing how various 5w30 conventional oils are. We all know GC is an extremely good oil at extremely cold temps, but it also is a bit thicker at normal temps (such as 0C) than most 5w30 oils are.

 

[Drew99GT]

Just plug the 40 and 100 degree viscosities in here .

This only determines kinematic viscosity via viscosity index though and won't really tell the whole truth of say, CCS and MRV, which are the true indicators of an oils ability at the limit of cold. For instance, I compared 10w-30 Trop Artic syn blend to Pennzoil 5w-30 via the viscosity calculator; at 0 degrees F, 10w-30 Trop Artic has a lower kinematic viscosity. But I doubt it would be better in a cold cranking or mini rotary viscometer test.

But it's a general indicator of an oil's cold weather ability. Just my

of course!

 

[427Z06]

I use this calculator for all my posts to be consistent.

http://www.geocities.com/CapeCanaveral/3655/VI.html

CCS and MRV can't be extrapolated so you may as well just use the published specs. However, they're less then useful numbers unless your climate subjects your oil to temperatures close to the CCS and MRV rating temps.

As long as you stay above pour points of the base stocks, it should be a fair comparison.

 

[pbm]

Before finding BITOG I always assumed that a 0w30 would flow even better (faster) in NY winters than a 5w30. I now know that that is not necessarily the case (ie: Mobil 1 5w30 vs. GC 0w30). I do however realize that GC will flow faster in Antartic conditions than the 5w30 syn. I know I've asked this before but how does a full PAO syn 10w30 compare with dino 5w30? I ask because I have plenty of both in my stash and I wondered if the full PAO syn would be fine for a mid-February til June OCI in a 6 cyl. GM which calls for 5w30. It probably will see a few 10*F starts. The car has nearly 80K so its broken in. Thanks.

 

[Patman]

After plugging in some numbers for GC it's pretty darn thick at most temps! I know it's a very good performer in extreme cold, but in normal temps it's quite a bit thicker. It does work well in my Corvette with my longer trips, but it's never done all that well in my wife's Honda (and with her short trips, now I see why, as it was pretty thick for most of the time she was driving)

 

[Drew99GT]

Quote:

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Before finding BITOG I always assumed that a 0w30 would flow even better (faster) in NY winters than a 5w30. I now know that that is not necessarily the case (ie: Mobil 1 5w30 vs. GC 0w30). I do however realize that GC will flow faster in Antartic conditions than the 5w30 syn. I know I've asked this before but how does a full PAO syn 10w30 compare with dino 5w30? I ask because I have plenty of both in my stash and I wondered if the full PAO syn would be fine for a mid-February til June OCI in a 6 cyl. GM which calls for 5w30. It probably will see a few 10*F starts. The car has nearly 80K so its broken in. Thanks.

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A full PAO synthetic 10w-30 would do that with ease! Plug the numbers in and see for yourself. If it's Amsoil, then I wouldn't even give it a 2nd thought.

 

[pbm]

Actually its Pennzoil Performax, Exxon Superflo, Mobil 1 Synthetic (older PAO versions).

 

[FD777]

I believe 427Z06 posted the table. I had it linked in the GC FAQ, but the old links no longer work

And as mentioned, he used a VI calculator to extrapolate those values.

Edit: Doh, he already posted...

 

[AndyH]

Quote:

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I believe 427Z06 posted the table. I had it linked in the GC FAQ, but the old links no longer work

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Perhaps not the one that you had linked to in the GC FAQ, but here is one he posted on December 8, 2006:
Code:

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Calculated Kinematic Viscosity in cSt, Temps in Centigrade



T(C) GC 0W30 M1 5w20 M1 5w30 M1 0w30

-20° 2609 1922 2604 2573

-10° 1127 811 1107 1089

0° 547 388 531 520

10° 292 206 281 274

20° 169 119 161 157

30° 104 74 99 97

40° 68.4 48.3 64.8 63.1

50° 47.0 33.4 44.4 43.2

60° 33.7 24.0 31.7 30.9

70° 25.0 17.9 23.5 22.9

80° 19.1 13.8 18.0 17.5

90° 15.0 10.9 14.1 13.7

100° 12.0 8.8 11.3 11.0

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From this message thread:
Which Flows Better in Cold Weather GC or M-1 5w30?

He has posted others in the past as well.

 

[Patman]

The numbers at 10 and 20 degrees look wrong for M1 5w30, they are way too low.

It's funny how we worry about an oil that is 1 or 2 cst different at 100c, when the oil varies by way more than this at colder temps, and it's also considerably thicker at those temps than many people realize!

 

[oilyriser]

"This program can be used to estimate viscosity or viscosity index for liquid petroleum products"

Are the calculations accurate for synthetic fluids?

 

[AndyH]

Quote:

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The numbers at 10 and 20 degrees look wrong for M1 5w30, they are way too low.

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Good eye Pat, I inadvertently screwed up a couple of the numbers when I copied & pasted from the other thread and then attempted to line-up the columns a little better. I've corrected my post above.

 

[427Z06]

Quote:

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The numbers at 10 and 20 degrees look wrong for M1 5w30, they are way too low.

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Copying error. Look at my original post.

http://theoildrop.server101.com/forums/showflat.php?Cat=0&Number=774951

Further, this is with current Group III M1. The previous M1 versions were substantially thinner at lower temps.

http://theoildrop.server101.com/forums/s...5016#Post775016

 

[427Z06]

Quote:

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"This program can be used to estimate viscosity or viscosity index for liquid petroleum products"

Are the calculations accurate for synthetic fluids?

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YES.

 

[AEHaas]

I always wonder why people are obsessed with 1 or 2 cS differences at 200 F yet ignore the 20 or 50 cS differences at 75 F start up. That 1 or 2 cS difference is meaningless whereas that 50 cS difference is all important to my way of thinking.

aehaas

 

[Patman]

Quote:

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I always wonder why people are obsessed with 1 or 2 cS differences at 200 F yet ignore the 20 or 50 cS differences at 75 F start up. That 1 or 2 cS difference is meaningless whereas that 50 cS difference is all important to my way of thinking.

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It's taken me a while, but I am now coming around to your way of thinking Doctor!

Especially on short trippers, you want something that is going to flow much better during the initial few minutes of engine operation, where most of the wear is going to occur.

But you still have to be careful not to go too thin on the big end if you're going to see high oil temps for long periods of time.

 

[427Z06]

Good work, Doc. Especially if you brought a new perspective to Patman.

I've posted viscosity charts for years and very few payed them any attention until you came along.

 

[Patman]

Quote:

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Good work, Doc. Especially if you brought a new perspective to Patman.

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Yep, I'm man enough to admit I've been somewhat wrong in my way of thinking in the past, and focused too much on the viscosity at 100c instead of looking at the bigger picture. I'm sure a lot of people have changed their way of thinking since viewing all the UOAs posted on here in recent times, showing that lower viscosity oils are performing extremely well.