What viscosity do you end up with when you mix?

This example is like measuring battery capacity in "miles" instead of kWh, it might seem "easier" but it's ultimately nonsense because it's trying to apply a static measure to a variable or range. You think you are helping by making it "simple" but ultimately, by avoiding the proper units, you are just furthering ignorance because the person doesn't leave the conversation with any greater understanding of the material than when they arrived.

There is no "seat of the pants number" because grades are clearly defined ranges in SAE J300, which has been posted countless times on this forum and should be the basic starting point for anybody interested in this subject.

Clearly, the OP appreciated a more detailed and accurate answer, given his response to my reply.
Thats condescending to claim I am "furthering ignorance". There is no need take a shot like that. I am not surprised though, since you have 60K posts here, and you very much like to debate. I get that. This subject has come up before. Its not germane just to this thread or poster. No one is claiming 12.5 is technically valid number, but it certainly does give the gist where the viscosity lands, at least to those who can understand the nuance of it. Maybe you just can't.

Technical precision has its place. I have a 40 year career of technical precision with analytical chemistry in a QA/QC laboratory. I have great experience with gas and liquid chromotography, and GCMS. I work with ppm and ppb analysis daily. I don't need a condecending lecture on technicalities. I understand precision and technical accuracy more than most anyone but a high degree of such is not necessary to convey a simple idea. Some people miss the forest for the trees. I do not envy them.
 
Thats condescending to claim I am "furthering ignorance". There is no need take a shot like that. I am not surprised though, since you have 60K posts here, and you very much like to debate. I get that. This subject has come up before. Its not germane just to this thread or poster. No one is claiming 12.5 is technically valid number, but it certainly does give the gist where the viscosity lands, at least to those who can understand the nuance of it. Maybe you just can't.

Technical precision has its place. I have a 40 year career of technical precision with analytical chemistry in a QA/QC laboratory. I have great experience with gas and liquid chromotography, and GCMS. I work with ppm and ppb analysis daily. I don't need a condecending lecture on technicalities. I understand precision and technical accuracy more than most anyone but a high degree of such is not necessary to convey a simple idea. Some people miss the forest for the trees. I do not envy them.
But that’s the thing. You have no idea if that’s where the viscosity lands. Because you don’t know where the two oils start you therefore don’t know where the mixture ends.

Even if you did know this then what’s the viscosity of a 12.5W supposed to be? All anyone is doing here is making up stuff that has no basis in reality and does nothing to help out the OP.
 
Mixing a MV formula with another MV formula - where each company has dozens of options on base stock, VM’s, PPD, and other additives - will yield a questionable lubricant - and nobody should care what the viscosity curve will look like - just say no !
 
But that’s the thing. You have no idea if that’s where the viscosity lands. Because you don’t know where the two oils start you therefore don’t know where the mixture ends.

Even if you did know this then what’s the viscosity of a 12.5W supposed to be? All anyone is doing here is making up stuff that has no basis in reality and does nothing to help out the OP.
Ditto - Looks like I was typing some similar at the same time …
 
Thats condescending to claim I am "furthering ignorance". There is no need take a shot like that.
It wasn't meant to be a shot, just a statement of fact. If a mix of two oils comes in with a CCS at -25C of 6,200cP then the Winter grade is 10W (assuming MRV is below 60,000cP at -30C, which it almost assuredly would be). If that isn't explained and somebody makes up a grade that doesn't exist in J300, the person who asked the question is no further ahead than when they started; they've gained no knowledge because they don't understand J300, what the grades are or how they are defined.
Technical precision has its place. I have a 40 year career of technical precision with analytical chemistry in a QA/QC laboratory. I have great experience with gas and liquid chromotography, and GCMS. I work with ppm and ppb analysis daily. I don't need a condecending lecture on technicalities. I understand precision and technical accuracy more than most anyone but a high degree of such is not necessary to convey a simple idea. Some people miss the forest for the trees. I do not envy them.
What does any of that have to do with making up grades that don't exist in J300? What benefit does calculating a number that doesn't represent anything, since what you are trying to represent is already clearly defined by the ranges listed in J300, bring to a discussion where somebody is trying to understand the topic?
 
Last edited:
No one is making up anything, or redefining any official metrics. They are just conveying a a ball park answer where something roughly lands. Never meant or implied to be "technically correct". Clearly, you just can't "get it".
 
No one is making up anything, or redefining any official metrics. They are just conveying a a ball park answer where something roughly lands. Never meant or implied to be "technically correct". Clearly, you just can't "get it".
Speaking myself as someone who worked in a corporate research laboratory for many years, Overkill is not the one who isn’t getting it here.
 
No one is making up anything, or redefining any official metrics. They are just conveying a a ball park answer where something roughly lands. Never meant or implied to be "technically correct". Clearly, you just can't "get it".
The 12.5W grade is being "made up" because it isn't defined in J300. Furthermore, you can't calculate the Winter grades anyway, since they aren't based on KV100 like the SAE grades are and the behaviour of components below 0C isn't consistent. I understand perfectly what's being attempted, but my point is that the figure is useless and doesn't help anybody understand the subject. It's like saying the result is "banana", which is equally undefined in J300 and just as useful.
 
The base oils blend as do the VII's and the PPD's so you end up with an overall heavier base oil blend than the 5W-30 and a lighter one than the 20W-50. The resultant KV100 is easily calculated, but the Winter grade is more difficult because of how bases behave below 0C as wax crystal formation starts. While there was sufficient PPD content to make a light (probably 4cSt) base oil pump low enough and stay light enough to pass CCS at -25C, the 20W-50 likely had a much heavier base which, even with the PPD's, will still skew the overall blend heavier and thus carries a potentially heavy (no pun intended) penalty on the Winter grade performance testing.
And once this mix has some miles and oxidizes a bit, that can make the situation even more convoluted.

Point is, if cold-temp performance is critical, mixing is not a good idea.
 
Speaking myself as someone who worked in a corporate research laboratory for many years, Overkill is not the one who isn’t getting it here.
A "corporate research laboratory" is NOT where a typical end user wondering about a random viscosity mix is living.

Ivory tower thinkers just can't "get" this.
 
My adult kids (for some reason) have taken to adding "-ish" to things. I don't know why but they picked that up somewhere. If I ask them how hot it is outside, they tell me "90-ish". If I as them what time do they want to eat dinner, they tell me "7-ish" or whatever.

I don't particularly like the -ish verbalization, but I am smart enough to know what the means! "12.5" is in the same vein. It is not an official ASTM viscosity and no one claims it is, but just like "90-ish" is not in any way an official temp, it certainly gets the message across. Its easy to understand to anyone, except to those who are so rigid minded they just can't see the intention. I feel for those willfully unable to understand something this simple. Its sad.
The obvious difference with time is that there are numbers around the time. If I say "7-ish" that could mean 6:50, 6:55, 7:00, 7:05, 7:10...etc, all times that exist and are around 7. The same goes for temperature, 90-ish could mean 85 degrees, 87 degrees, 91 degrees, 93 degrees, these are all valid temperatures.

If I say "10.5W" well, there is no 9.75W or 10.5W, they don't exist, it's either 10W or it's 5W or it's 15W, there aren't any intermediate numbers so inventing ones that aren't defined isn't useful. There aren't the equivalent of minutes or degrees between the grades, because they are defined as ranges meant to represent a specific level of performance as defined under J300. If your kids were saying "booger" when asked the temperature or "ear wax" when asked the time, that's about the same as inventing undefined grades here and just as useful.
 
A "corporate research laboratory" is NOT where a typical end user wondering about a random viscosity mix is living.

Ivory tower thinkers just can't "get" this.
I would never have mentioned my employment history had you not brought it up as justification for your “understanding” of terminology.

You’re digging a deep hole in this thread and it’s getting deeper.
 
A "corporate research laboratory" is NOT where a typical end user wondering about a random viscosity mix is living.

Ivory tower thinkers just can't "get" this.
🍿 🍿 🍿 The hole is getting larger.

You’re digging a deep hole in this thread and it’s getting deeper.

I spent 15min formulating a reply.. deleted it and came up with the same reply 😂
 
A "corporate research laboratory" is NOT where a typical end user wondering about a random viscosity mix is living.

Ivory tower thinkers just can't "get" this.
As a typical end user, wouldn't you take the advice from an "Ivory Tower Thinker" (read: expert)?
I would instead of listening to Joe Pops at the Feed store.
 
Back
Top