Advantages of PAO over Group III: What has changed?

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Historically, I was conditioned to believe that PAO base oils held a material advantage over Group III or GTL in terms of oxidative stability, cold flow performance and consistency of performance (due to the varying quality of Group III base oils). As a result, it was understood that certain OEM oil standards could not be met without significant usage of PAO.

However, some well-respected members have recently said that PAO’s only hold an advantage in cold temperature performance. Furthermore, they have stated that Group III blends can have better additive response and the finished product performance can be comparable to a PAO based synthetic.

So, have the fundamentals really changed, or is it simply the opinion of a few that PAO’s have very limited advantages?
 
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No they haven't. When formulated right PAO is the best. Only draw back is cost/availability. B/c GTL+ has largely closed the performance gap and is way cheaper, PAO is going the way of the dodo. It only remains in formulations b/c they don't have enough high grade gr III + to hit the new specs.

Remember, the industry was tooled up for what was on the road and what was selling. Cheapo 5w-30 and 5w-20 is what a lotta shops buy for the old cars (and maybe some new ones too, but thats another ball of glue).

So now dexos1 gen3, GF-6, and API SP all drop and piles of new cars rolling out with 0w-16 and 0w-20. It was a double whammy. You can only hit those specs in those weights with better group IIIs and GTL. So PAO's day of execution was delayed. But as you can see with Mobil, the biggest producer of the stuff, they keep reformulating PAO down year after year.

So its back to 5k oil changes, especially on these hotter power dense engines. they are driving more horsepower through smaller displacement than ever, and the base oils are going down in quality on the highest end motor oils.
 
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So now dexos1 gen3, GF-6, and API SP all drop and piles of new cars rolling out with 0w-16 and 0w-20. It was a double whammy. You can only hit those specs in those weights with better group IIIs and GTL. So PAO's day of execution was delayed. But as you can see with Mobil, the biggest producer of the stuff, they keep reformulating PAO down year after year.
My understand is that historically you can only hit those weights with PAO and that advancements have allowed the use of Gr3+ as a cost reducer.
 
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Historically, I was conditioned to believe that PAO base oils held a material advantage over Group III or GTL in terms of oxidative stability, cold flow performance and consistency of performance (due to the varying quality of Group III base oils). As a result, it was understood that certain OEM oil standards could not be met without significant usage of PAO.

However, some well-respected members have recently said that PAO’s only hold an advantage in cold temperature performance. Furthermore, they have stated that Group III blends can have better additive response and the finished product performance can be comparable to a PAO based synthetic.

So, have the fundamentals really changed, or is it simply the opinion of a few that PAO’s have very limited advantages?

Interesting. I always understood that Gr3 and PAO were very similar in performance. Especially when you compare Gr3+ to PAO. What I found odd was that some companies (ex, LiquiMoly) would only advertise PAO oil which had older certs (ex LL98, API SL) whereas the current offerings would be Gr3.
 
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I’m trying to figure out what exactly this group lll+, is.

This recent (or not so recent) if I’m reading this write, this article says GM claims there is a slight dip in performance when switching from a group lll, to a group lll+. Now, I don’t know if there also would be a dip in performance when switching from a grouplll to a POA either...nor do I know what they’re exactly talking about.

 
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I’m trying to figure out what exactly this group lll+, is.

This recent (or not so recent) if I’m reading this write, this article says GM claims there is a slight dip in performance when switching from a group lll, to a group lll+. Now, I don’t know if there also would be a dip in performance when switching from a grouplll to a POA either...nor do I know what they’re exactly talking about.

My understanding is that Gr3+ has a VI of around 130-150 whereas Gr3 is over 120. I know it has been mentioned that as Gr3+ gets closer to the performance of PAO it also takes on more of the negative attributes as well (i.e. additive solubility, seal compatibility?). So perhaps the article is speaking about a situation where a 3+ oils should be blended as if it were PAO because they're finding that Gr3+ blended like Gr3 isn't performing as well.
 
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Historically, I was conditioned to believe that PAO base oils held a material advantage over Group III or GTL in terms of oxidative stability, cold flow performance and consistency of performance (due to the varying quality of Group III base oils). As a result, it was understood that certain OEM oil standards could not be met without significant usage of PAO.

However, some well-respected members have recently said that PAO’s only hold an advantage in cold temperature performance. Furthermore, they have stated that Group III blends can have better additive response and the finished product performance can be comparable to a PAO based synthetic.

So, have the fundamentals really changed, or is it simply the opinion of a few that PAO’s have very limited advantages?
PAO, GTL, and to a lesser extent severely hydrocracked G3 all have additive solubility problems, particularly PAO. That's why esters and alkylated napthalines were introduced as carriers for additives. And here another problem emerged, esters are very polar and will definitely compete with additives for contact sites. It's not about what an oil is, it's about what an oil does.
 

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PAO has better oxidative stability and better cold temperature performance. HOWEVER, you can improve both of those things in a Group III base using additives and PPD's to the point where it doesn't matter much, if at all, depending on the oil being blended. If you need both, you'll likely still end up with PAO, which is why we see it still in many of the 0W-xx oils.

This has become particularly true with Shell's GTL bases, which have less wax in them and excellent specs. They would need less "help" in the cold temp performance department than more traditional Group III bases. We are seeing this with a number of Mobil products that, when reformulated, are using more, less expensive, GTL, than PAO. Also, GTL and Group III, while also having poor additive response (like PAO) doesn't have the seal shrink tendency, so you have more freedom with the rest of the formulation and can skip using esters to counteract that, reducing blending cost.
 
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GTL slots very nicely between PAO and Group III:

1658188820935.jpg


You can watch the full video here:
 

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I’m not sure much has “changed”, I recall posting literature screenshots a decade ago that showed the reasonably close performance of group III in terms of oxidative stability, as compared to PAO. We are obviously seeing that type of performance attribute which is why various group III basestocks are being used to achieve spec-meeting products in the face of ever more challenging requirements.
 
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We WERE here many years ago on BITOG and it seems lately the base oil wars have come out full force.
It is odd it seems everything is slowly shifting from certification and specs to base oil composition, could just be me though not sure
 
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It is odd it seems everything is slowly shifting from certification and specs to base oil composition, could just be me though not sure
I've been afflicted by the "base oil sickness" for a long time. It took time to get it into my head that it's more important what a lubricant does than what a lubricant is. You can have the best ingredients, but if you don't know how to use them, don't have competent staff, and a suitable additive supplier, then all the PAO, POE, and ANs in the world won't help you make a good product. It took a few years and some experimenting to come to this conclusion.
 
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If you look at the NA vehicle population as a whole, I believe that the "average" quality of motor oil has gone up considerably in the last decade as Grp III usage becomes pretty mainstream. The PAO vs Grp III discussion only applies to a miniscule slice of users.

A number of vehicle forums I frequent for brands that would be considered (at best) mediocre quality are filling up with questions from folks with 300,000 plus miles and the original motor.
 

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It is odd it seems everything is slowly shifting from certification and specs to base oil composition, could just be me though not sure
Eh, I like looking at both. My current fixation is the full-SAPS euro certifications, because I believe they were truly a "no holds barred" approach in terms of AW chemistry. On top of that, I don't use block heaters and sometimes have to deal with -30C, so I want some PAO in the base oil blend, preferably a lot of it if possible so the oil isn't dependant upon PPD's.
 
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Eh, I like looking at both. My current fixation is the full-SAPS euro certifications, because I believe they were truly a "no holds barred" approach in terms of AW chemistry. On top of that, I don't use block heaters and sometimes have to deal with -30C, so I want some PAO in the base oil blend, preferably a lot of it if possible so the oil isn't dependant upon PPD's.
I’d say my current fixation has become lots of esters in the base oil blend idk why but here I am that and running 40 grades again not sure why
 
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My understand is that historically you can only hit those weights with PAO and that advancements have allowed the use of Gr3+ as a cost reducer.
Yes i think thats what i was saying, the lower cost replacement has been scaling up. PAO is still used for now, i'm making more of a prediction here that over time gr III+ kicks out more and more PAO, and it just hasn't happened completely yet b/c there's not enough of the new stuff yet as the demand for 0w16/0w20 keeps shooting up.
 
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