Kublin Method--the ultimate oil-change strategy?

[Rexman]

Have any of you seen this before? It's the Kublin Method over on the Paradise Garage site (Theory #5):

Paradise Garage--Oil Change Theories

At first glance, I liked this method a lot because:
a) It’s simple—just find out the virgin TBN of the oil you are using and plug it into the formula. The other info you either know or can find out in your owner’s manual.
b) It takes into account the amount of horsepower relative to engine size—a great way to factor in the stress your engine is under.
c) It indirectly accounts for driving style by including your mpg. (More highway miles is much easier on the engine, so your drain intervals will be longer.)

But started to have some doubts when I saw Kublin works for Amsoil and only gives Mobil a value of 8 when it’s actual TBN is 11 or so.

Do you guys think this a valid way to figure oil changes, or has Kublin simply devised a clever way to promote the superiority of his product line?

[ July 16, 2003, 02:04 PM: Message edited by: Rexman ]

 

[3 Mad Ponchos]

Although the equations remain unchanged, that page needs to be updated with more current data points and new TBN methodology from the lab.

I'll take care of it when the M1 test is complete. Otherwise I may just end up revising it again anyway.

Cheers, 3MP

 

[widman]

If I used those formulas I would see very few oil changes and a lot of wear. None take contamination into account. Nor do they look at viscosity increase or decrease. In more than 1000 analisis that I've done none of the two brands I seel have ever come to close to reduced TBN, even with 20,000 km of mountains, sand, and mud. But I've seen Brazillian, Bolivian, and Argentine oils that lose their TBN in 5,000 km or less. I've seen people push Delo past 900 hours of heavy work in farm tractors with poor diesel without the TBN dropping below 4.5, but even the best air filters will put a serious amount of dirt in the engine in that time.

 

[Patman]

quote:

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Originally posted by widman:
If I used those formulas I would see very few oil changes and a lot of wear. None take contamination into account. Nor do they look at viscosity increase or decrease. In more than 1000 analisis that I've done none of the two brands I seel have ever come to close to reduced TBN, even with 20,000 km of mountains, sand, and mud. But I've seen Brazillian, Bolivian, and Argentine oils that lose their TBN in 5,000 km or less. I've seen people push Delo past 900 hours of heavy work in farm tractors with poor diesel without the TBN dropping below 4.5, but even the best air filters will put a serious amount of dirt in the engine in that time.

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That is a very good point, and many people overlook air filtration and instead blame their poor wear numbers on the oil.

Although at the same time, most of us in North America never have to deal with the harsh dusty driving conditions that some parts of the world see. Driving on unpaved roads is a whole different ballgame.

 

[Jay]

I think Ted Kublin's (aka TooSlick) method is the best of those shown. It's reasonably accurate for the vehicles I've tried it on.

 

[Patman]

Another thing to keep in mind, Ted devised this method to approximate how long to go between changes, but to also back it up with UOAs.

 

[doyall]

Saw an interesting method yesterday (wish I could remember the URL) for determining if oil needed changed: the business card method ... put a drop of oil from the dipstick on a business card - if it separates leaving a dark spot surrounded by lighter area, it's time for a change. (Or something like that.) Nothing real complicated there! Didn't try it but can't help but think it would result in either an extremely short or an extremely long interval.

 

[Rexman]

quote:

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Another thing to keep in mind, Ted devised this method to approximate how long to go between changes, but to also back it up with UOAs.

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Oops!--Looks like I really stuck my foot in it this time!

Didn't realize Ted was a member here and actually devised the formula on BITOG.com.

Sorry Ted, I'm going to try to take my punishment like a man.

 

[TooSlick]

Rexman,

The oil change formula posted over on the 3MP is NOT the correct one. This is the actual formula I developed:

OCI = (C*)(ave mpg)(sump in qts)(cubic inches/Hp)

Where C* is a constant which was derived by looking at oil analysis data I've accumulated over the last 10 years. For Amsoil I use a C* of 120, which generates drain intervals of approx 7500 miles for a turbo or motorcycle, up to 15k-20k for a low power density engine driven easily on the highway. If you have an application where you are dirt or soot limited, you can't use this formula and get a good estimation of oil life.

You CANNOT use the TBN times ten as a substitute for this C* value. The rate of TBN depletion varies significantly depending on the quality of basestock and additive chemistry. In addition, TBN depletion is non-linear, as you have seen from the 3MP tests. In other words, a 6 TBN oil will not last 50% as long as a 12 TBN synthetic. In actual practice, it might only last 25%-33% as long.

I don't have as much data on other oils as I do with Amsoil in deriving additional C* values. For Mobil 1 I suggested using a C* of 80, based on the limited data I've seen on this site. For an average quality petroleum lube, I think a C* of 40 is reasonable. The implication of using these various C* values is easy to see ....

Please feel free to contact me off-line if you have any other questions about this OCI formula. BTW, I've made my living as a propulsion engineer for the past twenty years - the Amsoil stuff is something I do on the side.

Tooslick.
Dixie Synthetics

 

[Rexman]

TooSlick,
Thanks for the added info. I think your formula goes a long ways towards finding the “Holy Grail” for drain intervals —the ideal mathematical formula that would tell each owner exactly when to change their oil for their particular vehicle and driving style.

Plus it’s simple and easy to use.

Good points made about it being tough to factor in for driving conditions—heavy dust, desert conditions, etc.—was thinking maybe the mileage result could be divided by some agreed-upon environmental constant (different values for different climates) that would reduce the drain interval to account for that. But maybe that would be too hard to quantify.

Also, the individual synthetics are so different in their composition, seems like it would pose a challenge to arrive at an accurate “C” constant in each case—some really good oils like Redline and NEO start off with lower TBN’s, but have the highest quality base stocks, and probably provide better protection than their UOA numbers show.

 

[Gary Allan]

quote:

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a 6 TBN oil will not last 50% as long as a 12 TBN synthetic. In actual practice, it might only last 25%-33% as long.

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I agree. The amount of acid needed to nuetralize the buffers in the oil should not be linear in it's effect upon the TBN. That is, the first half of the titration may have NO IMPACT upon the Ph of the oil. I'm not communicating this well here.

When I neutralize an acid waste product [industrial waste treatment] for distilation ...I may add a tremendous amount of caustic [sodium hydroxide]) to get the Ph from
So ...I would say that it probably has an "inversely proportional" or would that be inversely expotential

.

SOMEONE HELP ME ARTICULATE THIS, PLEASE

TBN start 12
TBN @ 6000 miles 6
TBN @ 7500 3
TBN @ 8250 1.5

This would assume a constant operating condition. If you applied my observations with my caustic adds ..you would plug in the time base to replace the mileage.

Imperfect analogy ..but that's how I "envision" it.

Critique????

 

[slider]

quote:

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Originally posted by TooSlick:

I don't have as much data on other oils as I do with Amsoil in deriving additional C* values. For Mobil 1 I suggested using a C* of 80, based on the limited data I've seen on this site. For an average quality petroleum lube, I think a C* of 40 is reasonable. The implication of using these various C* values is easy to see ....

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What value of C would you use for the Amsoil ASL 5W-30?

Thanks!

 

[3 Mad Ponchos]

quote:

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The oil change formula posted over on the 3MP is NOT the correct one

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C'mon TS, the website does in fact specifically state your constants. The only difference is that it lets the user try different constants if they want to.

Cheers, 3MP

 

[TooSlick]

3MP,

Keep in mind this is an empirically derived constant, in other words it is based on actual test data. I wouldn't want to say that two different oils would last the same amount of time simply because the TBN is the same.

Slider,

I'd probably use 120 for either ASL or ATM ....

I haven't got a clue what C* value to use for Redline, as the TBN data I see is all over the map....

TS

 

[Rexman]

quote:

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I haven't got a clue what C* value to use for Redline, as the TBN data I see is all over the map....

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The Redline UOA's are pretty baffling, and seem to defy rational explanation at times. Don't know whether I'm a real dare-devil or a complete idiot for running it in mine.

(Actually, I like the Redline a lot-- maybe we just haven't plumbed the secrets of its chemistry enough.)

Guess I'm curious why the C* for Amsoil is so high--never really thought of it as being 50% better than Mobil 1. Isn't the reason you can run Amsoil so long because of the advanced filtration system it uses, and not so much the properties of the oil itself?

 

[buster]

I don't think any oil is better 50% more then another. If anything, synthetics offer maybe only a small percentage benefit over conventional oils. It is hard to quantify something like this.

For extended drains, bypass filtration is the way to go. With cars like mine that hold only 4qts of oil, I can only get about 8k max out of Amsoil's 10w-30. My last report Terry stated that the oil could probably go another 3k miles max, and this was at 5k miles with a very well cleaned engine doing all highway miles. Sump capacities play a huge role.

 

[TexasTDI]

I like TooSlick's formula. It says I should change my oil every 22,800 miles.

It will be interesting to see how well it holds up against a UOA with 10k miles on the oil.

 

[buster]

quote:

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I like TooSlick's formula. It says I should change my oil every 22,800 miles.

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Hope you have a bypass filter.

 

[TooSlick]

TexasTDI,

For diesel engines I'd substitute ft-lbs of torque in place of Hp in the equation ...I feel this is a better measure of diesel engine output ....

A drain interval of 15k-20k is doable in the TDI with the Amsoil 15w-40 or Series 3000, 5w-30.

TS

 

[TexasTDI]

quote:

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Originally posted by TooSlick:
For diesel engines I'd substitute ft-lbs of torque in place of Hp in the equation ...I feel this is a better measure of diesel engine output ....

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Ahh...ok...let's see how the number changes:

Chipped 1.9 TDI
Oil TBN = 12
CI = 115
Oil capacity = 4.75
Torque = 229ftlbs
MPG = 40
Change oil every 11,450 miles - currently changing every 10k per VW's recomendation

Stock 1.6 D (no turbo)
Oil TBN = 12
CI = 97
Oil capacity = 4.75 quarts
Torque = 71ftlbs
MPG = 43

Change oil every 33,485 miles - seems awfully high to me, but would be nice if it were accurate. Although I doubt the OEM oil filter would last that long. It's only designed for 7500 mile oil changes.