TBN Depletion Graph for MC Syn Blend and PU

[badtlc]

Originally Posted By: kam327
Originally Posted By: badtlc
I don't get the price argument for MC. Every way I look at it, running PU is cheaper per mile than using MC.


PU would have to last 50% longer than MC every time in order to be the same cost per mile. Can you guarantee that?


I think you are looking at it in an odd way. If you run 5k mile OCIs with MC, you can run 8k+ OCIs with PU cheaper. If you run 7.5k mile OCIs with MC, you can run 12k+ mile PU OCIs for less $.

Do you not feel that PU and MC would handle those OCIs?

 

[kam327]

Originally Posted By: badtlc
Originally Posted By: kam327
Originally Posted By: badtlc
I don't get the price argument for MC. Every way I look at it, running PU is cheaper per mile than using MC.


PU would have to last 50% longer than MC every time in order to be the same cost per mile. Can you guarantee that?


I think you are looking at it in an odd way. If you run 5k mile OCIs with MC, you can run 8k+ OCIs with PU cheaper. If you run 7.5k mile OCIs with MC, you can run 12k+ mile PU OCIs for less $.

Do you not feel that PU and MC would handle those OCIs?


It's odd to base my opinion on data? I think based on the two available used oil analysis for the same engine in rougly the same conditions (based on similar mpg), MC can go somewhere around 10k miles and PU can go somewhere around 13k miles. That's a 30% increase that is not justified by the 50% price increase.

Please provide comparable used oil analysis that support your claim.

 

[kam327]

Originally Posted By: tig1
Originally Posted By: kam327
Originally Posted By: KrisZ
Originally Posted By: JAG
I think the people who only see faults in what you show are more likely to not have a good scientific background, which is ironic to me.


Kudos to the OP just for trying, but you don't have to have a scientific degree or background to know that a sample of 1 will not make a graph or even an estimate.
I would really like to know what scientific background accepts an estimate based on 1 sample and 1 data point. I could see a proposal or a business case for further sdudies, most likely on government dime, get approved, but then we know that people approving such things have no scientific background at all

.


Guys, guys, you're taking this way too seriously. I'm not trying to pass these graphs off as gospel.


Then why post it??


If I was considering it gospel I'd be dropping it on y'all and not looking back. I am in fact aware of the flimsines of the argument I'm trying to make and interested in some good data to the contrary. The majority of what I'm getting unfortunately is "That just ain't how it is" with no data to back it up. If you disagree, provide some data.

 

[badtlc]

Originally Posted By: kam327
It's odd to base my opinion on data? I think based on the two available used oil analysis for the same engine in rougly the same conditions (based on similar mpg), MC can go somewhere around 10k miles and PU can go somewhere around 13k miles. That's a 30% increase that is not justified by the 50% price increase.

Please provide comparable used oil analysis that support your claim.


Why? You don't have any used oil analysis to support your claim.

 

[kam327]

Originally Posted By: badtlc
Originally Posted By: kam327
It's odd to base my opinion on data? I think based on the two available used oil analysis for the same engine in rougly the same conditions (based on similar mpg), MC can go somewhere around 10k miles and PU can go somewhere around 13k miles. That's a 30% increase that is not justified by the 50% price increase.

Please provide comparable used oil analysis that support your claim.


Why? You don't have any used oil analysis to support your claim.


Uh-huh. Ooooook.

 

[KHP]

This test consists of very limited number of data samples and also one type of engine which is one that's probably very easy on motor oils. So I would say results are inconclusive at best.

As an example of where PU shines (from my experience):

I used a popular conventional oil in my Subaru Turbo EJ255 engine which known to absolutely chew up most energy conserving PCMO motor oils. Most people tend to prefer HDEO motor oil (i.e. Shell Rotella) in this particular engine due to the fact of it being an oil killer.

The conventional oil only lasted a good 2k miles before it was completely used up. TBN was ok but oil sheared well out of viscosity specs. This could result in severe engine damage as the EJ255 is very sensitive to lower viscosity spec. With PU in my engine the oil stayed in spec and with a good amount of TBN at 7,500 miles and above.

So the value per mile will vary among different engines. This is especially true when an engine is very tough on the oil where the value of a more expensive more stout oil is actually needed.

Majority of engines out in the market will rarely see the value in good synthetics. Which is why the factory specs conventional/semi-synthetic oils for those engines.

 

[badtlc]

Originally Posted By: kam327

Uh-huh. Ooooook.


I have. All I see is single TBN data points. You haven't run either oil out to TBN depletion to see where that point is. As has already been pointed out, if you did that, that line will carry on for quite a while, most likely much longer than what your graph would indicate.

But that doesn't really matter anyway because you don't have oxidation and other measurements for VOAs and used oil analysis. The MC base oil is more likely to be condemned based on the other measurements than the PU. It isn't an apples to apples comparison.

 

[kam327]

Originally Posted By: badtlc
Originally Posted By: kam327

Uh-huh. Ooooook.


I have. All I see is single TBN data points. You haven't run either oil out to TBN depletion to see where that point is. As has already been pointed out, if you did that, that line will carry on for quite a while, most likely much longer than what your graph would indicate.

But that doesn't really matter anyway because you don't have oxidation and other measurements for VOAs and used oil analysis. The MC base oil is more likely to be condemned based on the other measurements than the PU. It isn't an apples to apples comparison.


Metals, viscosities and other paramaeters were well within acceptable limits on both used oil analysis. Actually, iron was much higher in the PU car with only 1,000 more miles on the clock than in my MC car . He wrote that off to a trip through the mountains, but again overall mpg was within 2 mpg of mine.

This is simply my prediction based on 2 similar used oil analysis. You're free to agree or disagree. Snarky barbs are however not appreciated.

Since you do disagree, what I would very much appreciate is your own data to back it up. I'm not holding my breath.

 

[Coprolite]

Here's a different way to look at the math(using recent purchase):
$27 - $10 < $18

On my truck it is even more exaggerated, as 5w30 isn't in jugs at any WalMarts near me. The $18 would be too low.

 

[GMorg]

Although the following reference is getting old and was specifically directed to diesels, it fits the discussion.

To the OP, notice the variation observed in real data sets. If you try to pick individual points and draw a curve based on each single point, you should see the same trends, but you will get very different curves for the same oil.

Separately, you should notice curves that nearly cross as well as curves that diverge.

I think that your overall conclusions are probably correct, but your comparisons are accompanied by artificial precision. the TBN for PU will generally last longer than for MC, for a higher price. If your labor is of absolutely no value to you and you are using the same number of filters regardless of your OCI, then your estimates may be more accurate than it appears on the surface. You also seem to be assuming that TBN is the only factor that needs to be known to determine OCI.

http://oil-lab.com/downloads/TBN-1.pdf

 

[kam327]

I looked at that paper. Of course, in a complete study, there will be scattered data points. But in the end I would expect the regression curve to look like the ones I've drawn, just as they did in that paper. Wouldn't you?

I am not counting on artificial precision here. Notice I called my graphs "cartoons". I am making a prediction based on 4 data points. I would not testify in court to them. I would love to collect more data to support my hypothesis, but I'm not willing to spend the money.

Notice I also made reference (later in the thread) to wear metals, viscosity, etc. all of which were within limits in both used oil analysis.

My lesson learned here is to spend more time introducing my hypothesis next time, clearly emphasizing my assumptions and the known weaknesses in the argument. Many of you spent so much time criticizing the graph and using that criticism to shoot down the whole hypothesis, missing the forest for the trees. That was my mistake and I'll do better next time.

I do still believe that conventional and blends provide a better value than full synthetics and will continue to pursue data to support or refute that belief.

Until then, thanks for the discussion.

 

[kam327]

By the way, thanks KHP for sharing your experience. There are always exceptions like yours.

 

[Hokiefyd]

While I don't know if the graph is accurate (it is only using a few data points), you point out quite clearly that you're trying to "guess" at the topic, and I see this probably as you intended it: not as you trying to pass this off as truth, but instead you trying to generate some discussion on an incomplete thought (the graph). We know that only one UOA on two different oils doesn't define the whole world. We know that and you know that. You're not representing it as anything other than what it is: "here's my thoughts guys, what do you think."

I find the "why did you even post this" and other snarky comments to be not helpful, and not in keeping with BITOG's usually high standards of fostering good discussion on a topic like this. Maybe I can't speak for everybody, but I'm here to learn, and notional conversations like this are very valuable. If we all had the answers, we wouldn't need BITOG.

 

[badtlc]

Originally Posted By: kam327

Metals, viscosities and other paramaeters were well within acceptable limits on both used oil analysis. Actually, iron was much higher in the PU car with only 1,000 more miles on the clock than in my MC car . He wrote that off to a trip through the mountains, but again overall mpg was within 2 mpg of mine.

This is simply my prediction based on 2 similar used oil analysis. You're free to agree or disagree. Snarky barbs are however not appreciated.

Since you do disagree, what I would very much appreciate is your own data to back it up. I'm not holding my breath.


You asked for input. I can't help it you don't like input that doesn't agree with you. I can't provide evidence for YOUR situation. It has been stated several times that TBN is most likely the wrong measurement to compare proper operational lifetime between a convetional and synthetic oil. You need oxidation levels and other measurements for the beginning and the end to figure out what will actually signal the condemnation point of the oils. They likely won't be the same measurement. Your MC could likely be condemned based on oxidation before TBN where as the synthetic will more likely be something else like TBN. And of course, your TBN curves are useless as has already been stated and shown several times.