Understanding Viscosity and HTHS

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Originally Posted by d00df00d
Ah, okay. Thanks for clarifying.

ILSAC GF-4 is just API SM plus some other stuff tacked on. Same relationship between ILSAC GF-5 and API SN.

Also, ILSAC and API specs are meant to be backward-compatible. That means a GF-5 oil also meets GF-4, an SN Plus oil also meets SN and therefore SM, etc.

So, if you see a GF-5 oil, that means it also meets GF-4, SN, SM, etc. That means QSUD 5W-30 easily covers the SM + GF-4 requirement in your OM, so there's no contradiction between their spec requirements and their brand recommendation.

As to the "vagueness", maybe I'm misunderstanding your point (again), but I think what you're really seeing is that Hyundai intends for the engine to tolerate a wide variety of oils meeting very common specs. So, it's not that Hyundai is being obscure or noncommittal or anything; it's that they really do think (probably with good reason) that the engine doesn't care what oil you run as long as it's in the right ballpark. Makes sense for a mass-market engine meant to have easy maintenance around the world.

Does that help?

Oh, I agree that they are fine with running a wide variety of oils, which is partially the reason I started this thread as I was interested in different viscosities. It is/has been an interesting discussion, even if I didn't ask my question clearly. It's been a fun read.

That makes sense- I misunderstood the GF ratings. My mistake.
 
Originally Posted by Gokhan
Some people expressed doubts about my calculator, which I understand, but the more I use it, I appreciate what a powerful calculator it is. If you can determine the HTHSV of an oil using it, this is indeed remarkable!

It would be really remarkable if this were tested with some actual data, and not extrapolation. We still have the same problem. Algebraically manipulating an unverified relationship to spit out the value of a different variable still leaves us with an unverified relationship.
 
Originally Posted by Garak
Originally Posted by Gokhan
Some people expressed doubts about my calculator, which I understand, but the more I use it, I appreciate what a powerful calculator it is. If you can determine the HTHSV of an oil using it, this is indeed remarkable!
It would be really remarkable if this were tested with some actual data, and not extrapolation. We still have the same problem. Algebraically manipulating an unverified relationship to spit out the value of a different variable still leaves us with an unverified relationship.
Indeed; perhaps even more remarkable if it were peer reviewed and/or qualified by an independent objective process that is provable and repeatable. If this had been done BEFORE taking the outputs and conveying them as a fact, credibility would have been solidified.
 
Originally Posted by Virtus_Probi
Originally Posted by OilUzer
Originally Posted by Gokhan
... Some people expressed doubts about my calculator, which I understand, but the more I use it, I appreciate what a powerful calculator it is. If you can determine the HTHSV of an oil using it, this is indeed remarkable!

Speaking of powerful calculators, i have 3 old HP calculators (RPN type) and they are the best. i used to program them to solve all sorts of equations ...

Still use my HP15C from 1983...lost the programming manual years ago and don't remember how to do it anymore, though. There are better tools on a PC for that, anyway.
I think that calc has only used 3-5 sets of batteries in all those years...


One of my old scientific HP (29C) had a chargeable battery that went bad long ago when I was in college and the battery was $40 or $50 and kind of expensive. I think I paid over $150 for the calculator and didn't want to pay another $50. I was able to take the 2 rechargeable cells out of their housing by breaking 2 little clips and the connecting back cover and 2 AA batteries fits perfectly in there. No other mods (e.g. Soldering, etc.) required. Just plugs in perfectly. The part you break is inside and not visible once you put the cover back. iirc I may have bought a AA positive/negative spring contact plate for 10¢ to put inside the housing to connect the 2 AA's. that calculator still works but the leather case was disintegrated over the years. HP used to make quality stuff ...
 
Originally Posted by OilUzer

One of my old scientific HP (29C) had a chargeable battery that went bad long ago when I was in college and the battery was $40 or $50 and kind of expensive. I think I paid over $150 for the calculator and didn't want to pay another $50. I was able to take the 2 rechargeable cells out of their housing by breaking 2 little clips and the connecting back cover and 2 AA batteries fits perfectly in there. No other mods (e.g. Soldering, etc.) required. Just plugs in perfectly. The part you break is inside and not visible once you put the cover back. iirc I may have bought a AA positive/negative spring contact plate for 10¢ to put inside the housing to connect the 2 AA's. that calculator still works but the leather case was disintegrated over the years. HP used to make quality stuff ...

Nice calc hack there!
I'm pretty sure my HP15C was $90, which was a lot of money to my financially struggling parents at the time (1983). My TI calculator had just failed me during a pop physics quiz (the infamous stuck 8 issue) and I got a zero on it...every student in that class except for me and one gal had an HP calculator, so I told my mother that was what I needed. We drove to a little calculator store in a nearby suburb and she basically turned white when she saw the prices...I told her that was what I had to have if I wanted to keep my string of straight As going. She liked bragging to her friends about her smart little boy, so she found the money somewhere.
My leather case is doing pretty good except for one rectangular burn mark from the late '80s, I was using the calc as sort of a support for a power supply board I was working on and the gold can power resistor it was driving got super hot. I kept wondering what the funny smell was...
 
LOL, my 15C I bought in 1989...$354 Australian...was 1.5 weeks of on campus lodging
I bought Heywood's Internal Combustion Engine Fundamentals the year after for $148.

(Can buy an 11C for $110 in the next town)
 
Oh wow, can't believe I'm reading this about old HP calculators. Here's a pic of mine sitting on my desk as I read BITOG. I bought this back in 1982 as a Freshman ME major at Rutgers College of Engineering, and the nerd that I am, I still use the [censored] thing on a daily basis!

IMG_20190523_144454.jpg
 
Still have the HP 41C I bought in 1982 (pretty expensive for back then), but don't use it much today as there are many other ways to do calculations these days. Bought a couple of engineering related "modules" and the expanded memory module for it back then too. Wrote some pretty cool programs for engineering use (at least for back in those days with a hand held calculator).

HP 41C Cost in 1982.jpg
 
You even have the box it came in! That's great. Expensive too. I remember the 11c was around $100, if I remember correctly. It was before Amazon, so I can't go and search my order history.

Yeah, I use R programming language quite a bit, but still use the old HP for quick count checks and stuff. The old 11c was actually programmable which was pretty advanced back then:)
 
I used a company-owned desk-top HP with RPN at work 1982-92. After I got used to it, I liked it better than my personal TI scientific calculator---on which the buttons became unreliable, as someone else mentioned above.
 
The little rubber pad "feet" on the bottom of my 15C were gone after a couple of years and the nameplate fell off at some point that I don't even remember. The diagrams and tables printed on the back on the calc are almost completely worn off...but I would be lost without the little thing at work.
The non-RPN calcs we have at home are VERY hard for me to use!
Most of my friends in HS were wealthier than me and had the HP41C and the memory unit that fit on top that read funny little white strips. I was sorta jealous, but having the 15C after my disastrous experience with the TI-55II was good enough for me.
 
OT but occasionally I use my TI-81 for programming short programs and for quickie calculations my TI-30XA.

For more extensive scientific programming and simulations I use MatLab-Simulink.

When all the batteries and AC fails I use my non-electrified, non-solar/wind-powered, Pickettt Model N 1010-ES Slide Rule, similar to the one below.
grin2.gif


Slide Rule Pocket_slide_rule.jpg
 
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Casio fx-3600P was the flagship calculator when I was in college and everyone wanted to get one if they could afford it. I was envious of people who had one and eventually my sister bought me one and I was so happy! I still use it. The single coin battery lasts easily for a decade if not more.

[Linked Image]
 
Originally Posted by Gokhan
Casio fx-3600P was the flagship calculator when I was in college and everyone wanted to get one if they could afford it.

This was mine through high school and university. It still works, but hasn't seen much use in years:

[Linked Image]
 
Originally Posted by MolaKule
OT but occasionally I use my TI-81 for programming short programs and for quickie calculations my TI-30XA.

For more extensive scientific programming and simulations I use MatLab-Simulink.

When all the batteries and AC fails I use my non-electrified, non-solar/wind-powered, Pickettt Model N 1010-ES Slide Rule, similar to the one below.
grin2.gif



My dad was a chemical engineer and tried to teach me how to use a slide rule in high school. He gave me one to practice ... lol. I already had a calculator and wasnt too interested . It was amazing how quickly he could calculate even square roots and stuff with that thing!
 
Originally Posted by Gokhan
Originally Posted by RDY4WAR
It's a boutique brand, not common to this board, and I know the VII content because I'm good friends with the man who formulated it. In fact, we're putting together a one-off formula that's being tested this summer. I'll probably post a VOA of it here in the coming months.

The formula only works with the OCP VII. If it's a different type of VII, you need to use different constants for the VII viscosity-boost rate and VII temporary-shear rate. Most commercial oils use OCP VII these days because they have a hard time passing the industry and OEM tests for the engine and turbocharger deposits otherwise, but since boutique oils don't get tested and certified, they tend to use random additives.

Also, the absolute VII content is not significant, as the VII sold as a ready-to-use product can be diluted with a solvent oil to a varying degree.

The relative VII content is more relevant when you use my calculator.

In fact, the VII content is not even the main goal of the calculator and it's only an intermediate calculation. The main goal is to calculate the base-oil DV150, base-oil KV40, base-oil KV100, and base-oil VI. When these quantities are calculated, there is only a single adjustable parameter that was calibrated against the Exxon Mobil blending guide to be 13.7 (highlighted in red in the spreadsheet). This is the VII viscosity-boost rate and it doesn't require the knowledge of the absolute VII content, as the latter can be absorbed into the former since they multiply each other. In fact, this somehow compensates for different VII types, as chances are the VII temporary-shear rate and VII viscosity-boost rate are inversely proportional to each other and when multiplied, the variation of the effective parameter (taken to be 13.7) is smaller when the VII type is varied.

If you want to check my calculator, run it with the density, KV40, KV100, and HTHSV values for your boutique oil and calculate the base-oil viscosity index (BO VI) and see if that's correct. That would be the only real check to see if it's working. Note that you need to calculate the BO VI manually using the Widman VI calculator from the BO KV40 and BO KV100 values calculated.

Estimated base-oil (BO) DV150, BO KV40, BO KV100, and BO VI of selected oils
 
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