I am confused reading this.....

[chiks]

Mobil 1 5W30 API SN (lab tested 2011)
TBN = 7.5 (Total Base Number is an acid neutralizer to prevent corrosion. Most gasoline engine motor oils start with TBN around 8 or 9. And in use, this becomes depleted over time as mileage accumulates)

Mobil 1 5W30 Extended Performance (15,000 miles) API SN (lab tested 2011)
TBN = 7.9 (Total Base Number is an acid neutralizer to prevent corrosion. Most gasoline engine motor oils start with TBN around 8 or 9. And in use, this becomes depleted over time as mileage accumulates) .
The detergent, anti-wear and TBN components of this Extended Performance oil are either about average or below average for typical API SN oils (even though some of the components are a little higher than in its standard Mobil 1 counterpart). TBN eventually becomes depleted as miles accumulate on oil in service. That’s “one” of the primary reasons for changing oil in the first place, to replenish the exhausted additive package. And it’s not unusual to see TBN values drop by as much as 60% from the original value, in only 5,000 miles. And with this oil starting out with a fairly low TBN value to begin with, it would seem very unlikely it could ever go a whopping 15,000 miles without having the TBN totally depleted well before reaching that 15,000 mile mark. So, this extended mileage claim appears to be only an unsupported marketing gimmick.

But, for those interested in long drain intervals, I’d suggest sending in a sample of this oil and having it lab tested at about the half way mark of 7,500 miles to see how much, if any, TBN remains. But, of course motor oil is typically already dark, dirty, contaminated and in need of changing by 5,000 miles anyway.

Valvoline 5W30 SYNPower API SN ( lab tested 2011)
Moly = 0 ppm (anti-wear)
TBN = 7.1 (Total Base Number is an acid neutralizer to prevent corrosion. Most gasoline engine motor oils start with TBN around 8 or 9. And in use, this becomes depleted over time as mileage accumulates)

Complete details over here...
http://speedtalk.com/forum/viewtopic.php?f=1&t=28365

 

[tinmanSC]

Oh my goodness. I can't wait for the replies on this one! Can you narrow down exactly what you are confused by? For starters, dark oil at 5K miles does not mean change it (WARNING! This is an oil noob statement! Run form people who say dark = change!) and starting TBN is not a very good indicator of where the TBN will be half way though the drain interval. Even the TBN half way through is not a good indicator of the miles it will hit at a TBN of 1. TBN is not linear.

 

[dave1251]

Dont worry about it. There is good advice on doing a used oil analysis at 7.5K before proceeding further. Just use the knowledge you have and make a determination what is sound advice and what is not.

 

[chiks]

I am confused by the "expert" comments provided against each oil.

 

[dave1251]

Don't worry the poster on the other thread is a "internet expert" and if you challenge him, you will be informed that he has a masters degree in motor oil chemistry.

 

[CATERHAM]

Well for starters most PCMO TBNs do not start around 8 or 9.
Also one can't generalize on the rate of depletion without actually testing the oil in service.

 

[Pablo]

This is just another one of those useless virgin oil comparisons that pop up on the internet. Somewhat interesting I suppose, but utterly useless for comparison of predicted results. Just one (for example, there are more) reason this kind of thing is flawed: oils have many features, chemicals, properties that don't show up in a $20 VOA.

 

[The Critic]

In regards to the TBN, this is what one formulator had to say. The numerical value does not provide the entire story:

"This is one reason why higher levels of TBN’s can mislead you into thinking it is better when in fact all it is stating is that it has higher levels of detergents to keep the engine clean but the base oil can oxidize(or breakdown) faster than one with higher levels of antioxidants which prevents the acids by neutralizing the attacking acids as oppose to cleaning up the by products of the oxidized oil."