Where is a temperature vs viscosity graph of...?

[mechanicx]

Originally Posted By: OVERK1LL
Originally Posted By: mechanicx
I had always thought that a 0W or 5W viscosity rated oil met the nominal viscosity of that wieght oil at 0 Celsius. I guess it's not that simple. I wonder just how accurate that windman site's calculator graphs are in predict an oils actual viscosity curve?


You bring forth an interesting question though, and here's why:

M1 TDT 5w40 shows an MRV of 25,400cSt at -35C on the data sheet. Yet using Widman's calc, I get 32292.6......... That's a pretty big difference!


Can you tell what the nominal viscosity range is for a 5 weight oil at 0C and if M1 TDT 5W40's 0C viscosity falls in that range? I'm sure the answer to SAE viscosity rating is on this web site but I don't know where to find it.

 

[OVERKILL]

Originally Posted By: mechanicx
Originally Posted By: OVERK1LL
Originally Posted By: mechanicx
I had always thought that a 0W or 5W viscosity rated oil met the nominal viscosity of that wieght oil at 0 Celsius. I guess it's not that simple. I wonder just how accurate that windman site's calculator graphs are in predict an oils actual viscosity curve?


You bring forth an interesting question though, and here's why:

M1 TDT 5w40 shows an MRV of 25,400cSt at -35C on the data sheet. Yet using Widman's calc, I get 32292.6......... That's a pretty big difference!


Can you tell what the nominal viscosity range is for a 5 weight oil at 0C and if M1 TDT 5W40's 0C viscosity falls in that range? I'm sure the answer to SAE viscosity rating is on this web site but I don't know where to find it.


To throw a wrench in:

AMSOIL ASL 5w30 at 0C: 485.6
Mobil 1 TDT 5w40 at 0C: 1009.7

Those numbers aren't even close.

 

[mechanicx]

Originally Posted By: OVERK1LL
Originally Posted By: mechanicx
Originally Posted By: OVERK1LL
Originally Posted By: mechanicx
I had always thought that a 0W or 5W viscosity rated oil met the nominal viscosity of that wieght oil at 0 Celsius. I guess it's not that simple. I wonder just how accurate that windman site's calculator graphs are in predict an oils actual viscosity curve?


That is a very good question. And one I am not qualified to answer.


I'm not either that's why I ask

. I had always thought that SAE 5W30 meant it met a nominal viscosity of a 5 weight at 0C or 32F and 30 weight at 100C or 212F

.


Yup, that was my understanding as well. That the oil would emulate a straight 5-weight at 0 degrees Celcius, whilst being a 30W at 100C.

Of course the grades themselves encapsulate a somewhat broad range, so the lack of specificity is in itself, part of the confusion.


I think that windman graph maybe is just extrapolating an oil's viscosity curve from it's viscosity index and a formula. In reality an oil may not have a constant curve. Then you have different levels types of VII making things unpredictable

 

[OVERKILL]

Originally Posted By: mechanicx


I think that windman graph maybe is just extrapolating an oil's viscosity curve from it's viscosity index and a formula. In reality an oil may not have a constant curve. Then you have different levels types of VII making things unpredictable


Exactly what I was thinking.

 

[mechanicx]

Originally Posted By: OVERK1LL
Originally Posted By: mechanicx


Can you tell what the nominal viscosity range is for a 5 weight oil at 0C and if M1 TDT 5W40's 0C viscosity falls in that range? I'm sure the answer to SAE viscosity rating is on this web site but I don't know where to find it.


To throw a wrench in:

AMSOIL ASL 5w30 at 0C: 485.6
Mobil 1 TDT 5w40 at 0C: 1009.7

Those numbers aren't even close.


Yeah not very close. I'd assume the range would be tighter than that if the oil was being rated 5 wt at that temperature. Are these the official specs for the oil or the calculated ones? I assume they are the spec viscosity.

 

[crinkles]

Originally Posted By: mechanicx
I'm not either that's why I ask

. I had always thought that SAE 5W30 meant it met a nominal viscosity of a 5 weight at 0C or 32F and 30 weight at 100C or 212F

.


no no no!!!

http://www.tribology-abc.com/abc/viscosity.htm

the 5w and 0w means it meets a cranking viscosity and pumping viscosity value as per the table on the above link at a specified temperature (-30 C, -35C)

a 5w30 therefore has to meet:
the 5w spec -
Cranking viscosity of max 6,600 at -30 C
pumping viscosity of max 60,000 at -35 C

AND
the 30 spec -
9.3 - 12.5 at 100 Deg C
HTHS of min 2.9 at 150 Deg C

the above is what defines the numbers. it has nothing to do with any property at freezing point of water.

 

[jstutz]

The problem is you all are looking at temps that the graph is not accurate at. They tell you right on there page that the accuracy starts to degrade after 0C. So looking at temps much lower than that, is almost irrelevant becuase you cant trust the numbers. if you guys want to blow your mind, throw some 15w40 numbers in there.

 

[OVERKILL]

crinkles and jstutz:

Well that definitely limits the usefulness of the graph.

crinkles, using Widman's calc, TDT is 17380.1cSt at -30, but is 32292.6cSt at -35C. So I'm thinking jstutz statement here is making sense.

 

[m37charlie]

I have a technical article about CH4 Delvac 1 5W40. Unfortunately it is copy protected.
It has a graph. Viscosity is 50000 @-40C., 20000@-35C., ~10000@-30C., 3300@-25C.

Charlie

 

[jmac]

Originally Posted By: mechanicx
I had always thought that a 0W or 5W viscosity rated oil met the nominal viscosity of that wieght oil at 0 Celsius. I guess it's not that simple. I wonder just how accurate that windman site's calculator graphs are in predict an oils actual viscosity curve?


About as accurate as spittin' in the wind.

 

[pcfxer]

Originally Posted By: OVERK1LL
Originally Posted By: Gary Allan
Quote:
After graphing M1 0w40, ASL 5w30 and SSO 0w30, there really isn't a big difference between M1 0w40 and SSO 0w30 at any of the cold-start temps.


Well, I think I'd be negligent in not pointing out that SSO's numbers are BETTER than M1 0w-40 at all those temps ..

..not that it really means much... (I love it when I see this) "I'm just sayin' "

Hey, somewhere between -50C and -55C, M1 0w40 is thinner than SSO, and all lower temps. That in itself is weird.


Except that ASL Is ONLY thicker BELOW -35C. XLF and SSO are thinner. And, where the limit of the equations is noted as (zero degrees) Mobil 1 0w-40 is thickest...so you reiterated my point.

Thank you for the support.

Regardless, as was stated I forgot that the w rating is not based on viscosity at that temperature. It is the cranking (pressure?) ability at those temperatures that gives the rating.

 

[Gary Allan]

How a fluid reacts at cold temps doesn't relate to it's true viscosity. I can't even begin to comprehend what a centipoise (or poise) is to begin with. You need a certain amount of formal discipline to even understand the explanation to begin with. Not an easy task in self teaching without the aid of an instructor. ..but you're dealing with non-Newtonian properties of a fluid ..and attempting to apply that to our Newtonian rational on how we normally perceive resistance to flow ..aka: viscosity.

MRV spec's more conform to our general concepts.

 

[mechanicx]

Originally Posted By: crinkles
Originally Posted By: mechanicx
I'm not either that's why I ask

. I had always thought that SAE 5W30 meant it met a nominal viscosity of a 5 weight at 0C or 32F and 30 weight at 100C or 212F

.


no no no!!!

http://www.tribology-abc.com/abc/viscosity.htm

the 5w and 0w means it meets a cranking viscosity and pumping viscosity value as per the table on the above link at a specified temperature (-30 C, -35C)

a 5w30 therefore has to meet:
the 5w spec -
Cranking viscosity of max 6,600 at -30 C
pumping viscosity of max 60,000 at -35 C

AND
the 30 spec -
9.3 - 12.5 at 100 Deg C
HTHS of min 2.9 at 150 Deg C

the above is what defines the numbers. it has nothing to do with any property at freezing point of water.


OK well that's the explaination then,Thanks. Only the higher rating is the nominal viscosity at a certain temperature . You'd be surprised how many oil articles suggest the lower weight viscosity rating is the nominal viscosity of oil at 0C. I don't even pretend to have the straight dope on oil viscosity.

So if there is no minimum viscosity rating for a 5W at -30 and -35C and only a maximum, It makes it hards to calculate the viscosity curve accurately for a given oil?

 

[Gary Allan]

Quote:
So if there is no minimum viscosity rating for a 5W at -30 and -35C and only a maximum, It makes it hards to calculate the viscosity curve accurately for a given oil?



Not really. It only makes it difficult to communicate that just because you're using a 5w that you're not pumping cold molasses compared to another "5w" of lighter hot visc. It just means it will pump ..it doesn't mean that after it does flow that it will flow just as "easy" as another "5w".

To some a 5w-50 will be just as easy to pump COLD as a 5w-20 since both have the "5w". It just means that they will react the same at that cold state within limits. No sensible flow is occurring at those states.

Again, I can't even begin to understand the text of the physics involved ..but non-Newtonian properties/characteristics aren't indicative of Newtonian performance. (did I say that right?)

 

[OVERKILL]

Originally Posted By: pcfxer
Originally Posted By: OVERK1LL
Originally Posted By: Gary Allan
Quote:
After graphing M1 0w40, ASL 5w30 and SSO 0w30, there really isn't a big difference between M1 0w40 and SSO 0w30 at any of the cold-start temps.


Well, I think I'd be negligent in not pointing out that SSO's numbers are BETTER than M1 0w-40 at all those temps ..

..not that it really means much... (I love it when I see this) "I'm just sayin' "

Hey, somewhere between -50C and -55C, M1 0w40 is thinner than SSO, and all lower temps. That in itself is weird.


Except that ASL Is ONLY thicker BELOW -35C. XLF and SSO are thinner. And, where the limit of the equations is noted as (zero degrees) Mobil 1 0w-40 is thickest...so you reiterated my point.

Thank you for the support.

Regardless, as was stated I forgot that the w rating is not based on viscosity at that temperature. It is the cranking (pressure?) ability at those temperatures that gives the rating.


I wasn't reiterating your point at all and I'm not sure how my post supports your point about the 0w40 not being a 0w, when it is VERY close to SSO (a 0w) throughout the lower range. Regardless of how inaccurate the visc calc may be in the lower regions.

It is a 40-weight. I would expect it to be heavier than a 30-weight when warmer. If it wasn't, it wouldn't make sense, now would it?

 

[crinkles]

Originally Posted By: OVERK1LL
I wasn't reiterating your point at all and I'm not sure how my post supports your point about the 0w40 not being a 0w, when it is VERY close to SSO (a 0w) throughout the lower range. Regardless of how inaccurate the visc calc may be in the lower regions.

It is a 40-weight. I would expect it to be heavier than a 30-weight when warmer. If it wasn't, it wouldn't make sense, now would it?


it is only guaranteed to be heavier at 100 deg celcius and 150 deg C (if the HTHS higher spec of 3.7 applies for the 40 weight).

 

[OVERKILL]

Originally Posted By: crinkles
Originally Posted By: OVERK1LL
I wasn't reiterating your point at all and I'm not sure how my post supports your point about the 0w40 not being a 0w, when it is VERY close to SSO (a 0w) throughout the lower range. Regardless of how inaccurate the visc calc may be in the lower regions.

It is a 40-weight. I would expect it to be heavier than a 30-weight when warmer. If it wasn't, it wouldn't make sense, now would it?


it is only guaranteed to be heavier at 100 deg celcius and 150 deg C (if the HTHS higher spec of 3.7 applies for the 40 weight).


Guaranteed? yes. But as indicated by putting any number of heavier oils into the calc, most of them behave in the same manner.