Was looking for something I found yesterday regarding fuel economy and oil change interval...which got me to the machinery lubrication article here.
https://www.machinerylubrication.com/Read/29117/oil-change-intervals
Which had three theories for predicting max oil change interval based on engine parameters, one of which twas the "Kublin" method, mentioned here
https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=35017
Note that Ted Kublin used to be on BITOG as TooSlick (Dixie Synthetics)...the spacebears link is broken, but I found it on the wayback machine...
https://web.archive.org/web/20070701115905/http://neptune.spacebears.com:80/cars/stories/interval.html
The calculators even work...but here's the formulae that have been variously used, and demonstrated their "worth" in UOA.
So those of you who DO UOA's have a compare with where these suggest that you can go...
Don't have an OLM ???
- Thread starter Shannow
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Sweet info, Shannow! I used the Kublin method to run a quick comparison of my last UOA on the Fusion; at 17.2k there were some signs that I had likely reached a sane limit for OCI. I punched in 10TBN, 5.3qts, 151.5 cubes, 175HP, 33mpg.... and came up with about 15.2k OCI. I did it for my Odyssey as well, and it showed I actually shortchanged my OCI by about 800-1000 miles (which was accurate, considering the great result). Seems like a pretty close tool, especially if you have a reference VOA for the oil you're using.
I'll try this on my next OCI and see how the numbers look compared to historicals. Two thumbs up!
I remember the spacebars oci experiment and the kublin formula. It is really fun to play with different starting TBNs and services (resulting in different mpg averages)that effect mileage and therefore service life. Dusty [censored] roads and humidity are still to be consodered as extremely detrimental to oil life and formulas and OLMs do t account t for this.
Originally Posted by Shannow
Was looking for something I found yesterday regarding fuel economy and oil change interval...which got me to the machinery lubrication article here.
https://www.machinerylubrication.com/Read/29117/oil-change-intervals
Which had three theories for predicting max oil change interval based on engine parameters, one of which twas the "Kublin" method, mentioned here
https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=35017
Note that Ted Kublin used to be on BITOG as TooSlick (Dixie Synthetics)...the spacebears link is broken, but I found it on the wayback machine...
https://web.archive.org/web/20070701115905/http://neptune.spacebears.com:80/cars/stories/interval.html
The calculators even work...but here's the formulae that have been variously used, and demonstrated their "worth" in UOA.
So those of you who DO UOA's have a compare with where these suggest that you can go...
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If I did the math even remotely right then I got about 16k miles for my 6.0 PSD which is almost right where my UOA's put me for the OCI. If I did the math wrong then it's still pretty crazy that somehow came up with a number that close to my current OCI.
And I learn that my wife's 4 runner Can only go about 6700 miles at her current average mpg with dealer 0w20 in the sump...yet it will take a year to get there anyway so I may forgo the 6 month oil changes and save the effort and money.
Being my wife's grocery getter is more severe than my driving at high speed up grades between south central Texas and west Texas. [censored].yet due to mileage accumulated my vehicle will get more frequent oil changes on the calendar.
I try to drive her vehicle more when I at home, for tax reasons(I depreciate mine) and to improve the average MPGs she gets.
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I'm terrible at math. Whats all that stuff mean and how do I figure it out using that? I have no clue.
Wow, I really like the Kublin method. I entered the specs for my Subaru using a typical TBN for the lower-SAPS oil we're getting these days... and the interval comes up at 7683 miles, nearly identical to the factory recommendation of 7.5k! I like it Shannow, great find!
I was also playing around with numbers wondering why Subaru went back down to a 3750 mile OCI on all turbo motors. Using a TBN of 8 as recommended, the FA20T comes up at 4188 miles... leaving a cushion of roughly 10%. Looks like if I do pick up a 2015+ WRX it will be no more than 4k mile OCIs, with stout oils. The STI is better by only a couple hundred miles too...
I just did it and was 13,xxx.
Quite accurate as my uoa had over 4 on tbn at 10,000 miles oci.
12tbn
110 ci
37mpg
4qts
143hp
A big Thank you Shannow. Great info as always!
Its interesting i was searching for some pao vs. ester info and found some bitog threads as old as 2005 ... read some posts from TooSlick thinking this guy knows what he is talking about and clicked on his profile and I think last seen was 2014.
Shannow,
What is virgin bn?
in one of your link (kublin method) it's showing a constant c from 40 to 120.
Seems like c = (virgin bn)*10
I used the c=80 (I assume 0wx20 synthetic is considered good oil) for one car that I can remember the HP, and it came VERY close to OM oci
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Nevermind, virgin bn is tbn! I knew about tbn but the virgin thing confused me 
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Seems a little optimistic-my MGM comes up with a 17,800 mile OCI with a 9 TBN and avg. 20 MPG-maybe it should be called an "ideal conditions" AKA all hwy. miles OCI calculator.
It is more accurate if you track mileage for the entire OCI. Seasons change, driving habits can change too.
My vehicles let me track mileage over the oci with a manual reset. It would be. Otherwise just count how many gallons of fuel you burn and do the math.
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