Oil viscosity versus temperature calculator.

[SenorFunkyPants]

http://www.widman.biz/English/Calculators/Graph.html

An interesting gadget...type in the viscosity of an oil @ 40C and 100C and it will calculate the graph of viscosity against temp.

This is one I did for 10W60 against 0W40 using the viscosity @ 100C taken from the average of a load of UOAs for Castrol 10W60 and Mobil 1.

[dparm]

Yes, I've used that site for a long time. It's a good illustrative tool. I find it most interesting to understand how thick oils are at startup, i.e. 10-20 C.

Just a warning though, at low temperatures (below 0 C) it is not considered very accurate.

[SenorFunkyPants]

Cool...I wasn't sure how useful it was.
I was wanting to get an idea how thin the Mobil 1 might get, say at a track day with high ambient temps.

[dparm]

Originally Posted by SenorFunkyPants

Cool...I wasn't sure how useful it was.
I was wanting to get an idea how thin the Mobil 1 might get, say at a track day with high ambient temps.

HTHSV is the answer to that. It's measured at 150 C and should approximate viscosity in the hottest areas like bearings.

[e92zero]

interesting to see, but when is it too thin? does this actually mean 0-40 is not much different than 10-60 when hot but much better than 10-60 when cold? (which is what some of the other guys are trying to say all this time) what about film strength? is that constant throughout the temp range or is there some chart like this that we can plot also? Just trying to learn as much as I can and thanks for sharing the knowledge.

[SenorFunkyPants]

Viscosity, temperature, oil film thickness and film strength are all interconnected.
The viscosity of M1 0W40 at 210F is the same as the viscosity of the 0W60 at 240F....and IIUC they will have approx the same film strength and film thickness.
With both oils at 240F the 0W40 oil will be thinner, have less film strength and less film thickness.
The conclusion is that in cooler climates M1 0W40 would most likely be ok...but ill advised in a warmer climate where you see higher oil temps.

[dparm]

Originally Posted by e92zero

interesting to see, but when is it too thin? does this actually mean 0-40 is not much different than 10-60 when hot but much better than 10-60 when cold? (which is what some of the other guys are trying to say all this time) what about film strength? is that constant throughout the temp range or is there some chart like this that we can plot also? Just trying to learn as much as I can and thanks for sharing the knowledge.

It is too thin when you cannot maintain sufficient oil pressure.

And no, it does not mean that 0w40 and 10w60 are close when hot. The HTHSVs are quite different (3.8 vs 5.4, if you ignore any sort of temporary or permanent shearing).

[G80indy]

fascinating. And GREAT articles about wear and OCIs at this site.
Dirt hurts.

According to this calculator (very cool)
Redline 10w60 flows better than TWS Edge Professional 10w60 , M1 10w-60, and LiquiMoly 10w-60 at low temps, like below -4 F degrees!
by a hair, granted, but...
imagine that! And this is projected somehow and you guys are saying it's not accurate?
What is not being shown is how a group 5 oil behaves vs a group 3, at various temps. And that is very relevant to what I choose to put in the crankcase

[dereksM3]

Note that the M1 above at 100C is actually 13.5, not 12.5 according to the current M1 publications.

[SenorFunkyPants]

Originally Posted by dereksM3

Note that the M1 above at 100C is actually 13.5, not 12.5 according to the current M1 publications.

True for virgin oil...I used the viscosity for used oil averaged from oil analysis reports to give a better representation of the oils viscosity after it had sheared down.