Recent Topics
Interesting article about 5w-20 oil
by kenv
12/18/14 09:45 PM
(Unintentional) Bottle Aged Beer
by aa1986
12/18/14 09:28 PM
ADBV on Fram PH9837?
by Digital2k2
12/18/14 09:09 PM
Seeking Browning BLR-81 Information
by 2cool
12/18/14 08:54 PM
Ford Transits
by Eric Smith
12/18/14 08:32 PM
Ford 6F50 tranny
by Throt
12/18/14 08:22 PM
Probable Mercedes HQ move from NJ to Atlanta
by Joe1
12/18/14 08:22 PM
Army Proud
by GreeCguy
12/18/14 07:57 PM
Subaru Certified High Performance Gear Oil 75W90
by thescreensavers
12/18/14 07:49 PM
Ford Mustang 5.0L Stage 3
by lawman1909
12/18/14 07:21 PM
Purolator Oil pressure fluctuation.
by Joemc
12/18/14 06:40 PM
Air Conditioned Seats
by bobbob
12/18/14 06:13 PM
Newest Members
Joemc, gijello, joobert, mcresist, Milerhighlifeman
52219 Registered Users
Who's Online
105 registered (147_Grain, 4thstpositively, 2010_FX4, AandPDan, 2cool, aa1986, 13 invisible), 1345 Guests and 180 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
52219 Members
66 Forums
223619 Topics
3545803 Posts

Max Online: 2862 @ 07/07/14 03:10 PM
Donate to BITOG
Topic Options
#2276038 - 06/01/11 05:14 AM How important is TBN in Choosing an oil ?
vxcalais Offline


Registered: 07/14/07
Posts: 770
Loc: Melbourne, Australia
How much emphasis should be placed on a higher TBN oil for a 10,000 mile drain interval ? I traditionally go for tbn's of around 9 and above etc when choosing an oil. Some oils that have the same oil ratings may only have a tbn of 7 etc. Does this mean less additives or different additives ? For example, most SL/SM CI4 are 9 and above, yet some only have 7 and so on.
_________________________
Ride - Holden Calais VX GMV6 3.8litre 01

Top
#2276051 - 06/01/11 05:55 AM Re: How important is TBN in Choosing an oil ? [Re: vxcalais]
Colt45ws Offline


Registered: 08/15/06
Posts: 7514
Loc: Central Washington
It depends on the chemistry. Some seem to last longer for a given number than others. I wouldnt base much of anything on the starting TBN.
_________________________
-Colton
2004 Ford Crown Vic LX, 81k "Tank"
2002 Ford Crown Vic PI, 162k "Highwayman" (Ex-Kootenai County, ID Unit #42)

Top
#2276073 - 06/01/11 06:43 AM Re: How important is TBN in Choosing an oil ? [Re: vxcalais]
NateDN10 Offline


Registered: 01/10/10
Posts: 1432
Loc: Rochester, NY
In general, an higher starting TBN is better. However, some are better at TBN retention.

This is one place API SN oils should be better than their SM predecessors, for example.

What I typically try to do is to find UOAs with high mileage (7500+) on the oil to see TBN at that point. That's usually more telling than the starting TBN.
_________________________
2005 Chevrolet Cobalt - 85,000 mi.
2012 Mazda5 - 63,000 mi.

Top
#2276083 - 06/01/11 06:50 AM Re: How important is TBN in Choosing an oil ? [Re: vxcalais]
Jim Allen Offline


Registered: 08/12/05
Posts: 4477
Loc: NW Ohio
The best way to judge is by comparing starting and ending TBNs, with both the TBN tests done by the same lab. There are several methods for determining TBN and they read a little differently. You want to compare apples to apples with he same test methodology. That means a VOA with the oil you plan to use. A super-high TBN, around 10+, which you would find more common in the HDEO diesel rated oils, are not necessarily a good thing in a gas engine because they may leave more deposits and poison the cat faster (in a nutshell...much more to that). "High" starting TBN in a gas engine is 7-8. But like was said above, some TBNs start a little lower and hold longer and that counts for more than a high number that may drop precipitously.
_________________________
Jim Allen
Keepin' the Good Old Days of Four Wheeling Alive

Top
#2276084 - 06/01/11 06:54 AM Re: How important is TBN in Choosing an oil ? [Re: vxcalais]
vxcalais Offline


Registered: 07/14/07
Posts: 770
Loc: Melbourne, Australia
Thanks guys, some good advice for me to ponder. Tricky when you see oils with same ratings, claim high additives etc, but TBN's are clearly different.
_________________________
Ride - Holden Calais VX GMV6 3.8litre 01

Top
#2276130 - 06/01/11 08:37 AM Re: How important is TBN in Choosing an oil ? [Re: vxcalais]
INDYMAC Offline


Registered: 07/15/06
Posts: 2333
Loc: Magnolia, TX
I think the best way to look at this number is by how effective whatever TBN additives are used in the formula, relative to how well it is keeping TAN in check. A high starting TBN, or even reserve alkalinity at the end of an OCI means nothing if the chemistry of the oil allowed acids to build up unsafely. So, in short, don't pick the oil you want to use based on a higher starting or ending TBN alone. How effective the TBN is in use is more important.
_________________________
2013 Toyota Tundra DC 4X4 5.7L FFV
2012 Toyota 4Runner 2WD SR5
2004 Honda S2000

Top
#2276151 - 06/01/11 09:06 AM Re: How important is TBN in Choosing an oil ? [Re: INDYMAC]
daves87rs Offline


Registered: 02/23/09
Posts: 13646
Loc: Michigan
Originally Posted By: INDYMAC
I think the best way to look at this number is by how effective whatever TBN additives are used in the formula, relative to how well it is keeping TAN in check. A high starting TBN, or even reserve alkalinity at the end of an OCI means nothing if the chemistry of the oil allowed acids to build up unsafely. So, in short, don't pick the oil you want to use based on a higher starting or ending TBN alone. How effective the TBN is in use is more important.


Good food for thought.
_________________________
“The Only Thing Necessary for the Triumph of Evil is that Good Men Do Nothing.”

Top
#2276241 - 06/01/11 11:08 AM Re: How important is TBN in Choosing an oil ? [Re: NateDN10]
Hokiefyd Offline


Registered: 06/24/04
Posts: 11713
Loc: North Carolina
Originally Posted By: NateDN10
This is one place API SN oils should be better than their SM predecessors, for example.


I'm not challenging your statement, but asking for confirmation. I don't recall anything in the API SN description that would indicate a better TBN retention, but I'll be the first to concede that I could have missed it.
_________________________
Cheers,
Jason

2008 Honda CR-V EX-L (Peak 0W-20)
2005 Acura MDX Touring (VNG 5W-20)

Top
#2276246 - 06/01/11 11:15 AM Re: How important is TBN in Choosing an oil ? [Re: vxcalais]
NateDN10 Offline


Registered: 01/10/10
Posts: 1432
Loc: Rochester, NY
Oops, my bad. API SN calls for better ZDP retention, and I assumed that would help TBN as well. After a brief search around the internet, it appears that this is not the case.
_________________________
2005 Chevrolet Cobalt - 85,000 mi.
2012 Mazda5 - 63,000 mi.

Top
#2276377 - 06/01/11 02:14 PM Re: How important is TBN in Choosing an oil ? [Re: vxcalais]
dparm Offline


Registered: 04/19/10
Posts: 12583
Loc: Chicago, IL
It's only one aspect of an oil's performance. I wouldn't let it be the deciding factor.
_________________________
2011.5 BMW M3 saloon ZCP
der stärkste buchstabe der welt
Castrol Edge Professional TWS 10w60 + Mahle OX 254D3

Top
#2276423 - 06/01/11 03:41 PM Re: How important is TBN in Choosing an oil ? [Re: Hokiefyd]
addyguy Offline


Registered: 09/08/05
Posts: 13449
Loc: Canada
Originally Posted By: Hokiefyd
Originally Posted By: NateDN10
This is one place API SN oils should be better than their SM predecessors, for example.


I'm not challenging your statement, but asking for confirmation. I don't recall anything in the API SN description that would indicate a better TBN retention, but I'll be the first to concede that I could have missed it.


API SN protocol DOES call for oils to be able to handle E-85 fuels better. Higher alcohol levels, AFAIK, lead to higher contamination of the oils. Oils would have to retain TBN better to be able to handle E-85 fuel, so this first statement is correct.
_________________________
2003 Mazda Tribute LX V-6, 176k miles.
Castrol Edge SPT 0W-20; Fram EG2.

Top