TBN Depletion Graph for MC Syn Blend and PU

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kam327

kam327

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Over of focusfanatics another member recently posted his UOA with PU. Together with my own UOA I generated this TBN graph by backfitting an assumed TBN depletion line through the TBN measured at the UOA. Based on this cartoon, my MC Syn Blend shoul have lasted to roughly 9,800 miles (roughly the Ford-recommended OCI for this car) and his PU should have lasted to roughly 12,800.

His reported overall fuel economy is roughly the same as mine, an indication that his engine shouldn't be significantly harder on its oil than mine.

Based on $18 for MCSB and $27 for PU, cost per mile of MCSB is 0.18 cents versus 0.21 cents for PU.

Proof that syn blends provide a better value than the top store-bought synthetic?

Let the hole poking begin.

TBNGraph_zps327757af.jpg
 
There is the opinion that the TBN tends to drop and then stays there for a good so that would suggest you need more points on the graph to come to any conclusion.

In the end you would spend so much on UOA costs it would just be just as well to change the oil anyway.

eddie
 
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Not trying to poke a hole, but using MC might have been an unfair comparison. It's widely accepted here that MC is one of the best blends on the market, primarily because it supposedly contains a higher percentage of syn than most other blends.
 
Originally Posted By: RF Overlord
Not trying to poke a hole, but using MC might have been an unfair comparison. It's widely accepted here that MC is one of the best blends on the market, primarily because it supposedly contains a higher percentage of syn than most other blends.


Yes my assertion was probably overly broad. Maybe: "Proof that Motorcraft Syn Blend provides a better value than Pennzoil Ultimate."
 
Originally Posted By: Quattro Pete
Originally Posted By: RamFan
TBN depletion isn't linear...

Yup, and also what about TAN uptake?


Here's another more formal study which shows the TBN depletion graph has a slight curvature to it but is pretty darn close to linear.

Of course, this study warns against using TBN only as a measure of oil life. Which I don't disagree with. My graph is just one indication of the true value of a more reasonably priced oil.

http://www.oil-lab.com/downloads/TBN-1.pdf
 
Forgot to mention, the PU user had topped off before the UOA with a half a quart. I did not. So the graph is really improperly skewed in PU's favor and the MC value premium is even greater.
 
Originally Posted By: EddieCairns
There is the opinion that the TBN tends to drop and then stays there for a good so that would suggest you need more points on the graph to come to any conclusion.


I agree. It is very tough to graph something with only one point.
 
Originally Posted By: badtlc
TBN hardly ever fully depletes. It can even increase at times.

https://bobistheoilguy.com/forums/threads/tbn-over-time-and-amsoil-mobil-1-extended-study.186570/

It has been said before, and these studies seem to back it up, TBN will rarely ever get completely depleted.


You're kidding right? In the M1 study you pointed to they added 6 1/2 quarts of make up oil over the 18,000 mile OCI. Essentially replaced all the oil. That's the only reason TBN never fully depleted and "even increase[d] at times."
 
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Originally Posted By: asharris7
Never heard of Pennzoil Ultimate.....have heard of Ultra. . . . .
smile.gif



Ha! My bad.
 
Originally Posted By: kam327
Originally Posted By: badtlc
TBN hardly ever fully depletes. It can even increase at times.

https://bobistheoilguy.com/forums/threads/tbn-over-time-and-amsoil-mobil-1-extended-study.186570/

It has been said before, and these studies seem to back it up, TBN will rarely ever get completely depleted.


You're kidding right? In the M1 study you pointed to they added 6 1/2 quarts of make up oil over the 18,000 mile OCI. Essentially replaced all the oil. That's the only reason TBN never fully depleted and "even increase[d] at times."


Did you look at the amsoil one? there are other studies showing the same thing if you look around. plenty of info on this site about it.
 
Originally Posted By: badtlc
Originally Posted By: kam327
Originally Posted By: badtlc
TBN hardly ever fully depletes. It can even increase at times.

https://bobistheoilguy.com/forums/threads/tbn-over-time-and-amsoil-mobil-1-extended-study.186570/

It has been said before, and these studies seem to back it up, TBN will rarely ever get completely depleted.


You're kidding right? In the M1 study you pointed to they added 6 1/2 quarts of make up oil over the 18,000 mile OCI. Essentially replaced all the oil. That's the only reason TBN never fully depleted and "even increase[d] at times."


Did you look at the amsoil one? there are other studies showing the same thing if you look around. plenty of info on this site about it.


Yes and they added 4 quarts over 14,000 miles in that one. Depending on the car that could've been a complete sump flush as well.

By the way this is great data. Thanks for pointing me to it.
 
Originally Posted By: Donald
And this is only TBN. Oxidation is as important as TBN.


Understood there are other factors. This is not intended to be an end-all-be-all, just a thought provoker. Which is why I couched it with "Based on this cartoon...."
 
Fitting a curve based on a single UOA?
spankme2.gif


At least take samples every kilomile over the course of an OCI to get a better idea of what TBN & TAN are actually doing.
 
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