What are Friction Modifiers?

Joined
Nov 18, 2005
Messages
10,146
Location
Burlington, Ontario, Canada
That was a very informative thread but I do have a question. As I understand it, AW/FM additives such as ZDDP and moly are sacrificial, in so much that during boundary/mixed lubrication what's plated onto metal substrates is depleted as it's worn off since they are no longer in a reusable form? How does the usefulness of the initial AW/FM additive concentrations of fresh oil play out as mileage is racked up on an engine? In other words, is there a set depletion rate for AW/FM additives? For example, take a typical energy conserving motor oil with 600 ppm of phosphorus and 100 ppm of some organic moly type. How effective are the AW/FM additives at 3,000 miles, 5,000 miles, 10,000 miles and 15,000 miles vs the virgin oil? And how would this oil when fresh compare in it's ability to protect vs an oil with higher additive levels that had already accumulated say 10,000 miles? I think someone once posted that organic moly has lost most of it's effectiveness by 5,000 miles?
 
Joined
Apr 4, 2012
Messages
14,762
Location
Kendall, FL
I have a question "...<span style="font-weight: bold"><span style="font-style: italic">Esters, natural and synthetic fatty acids as well as some solid materials such as graphite and molybdenum disulfide are used for these purposes</span></span>..."Where do the Sodum based lubricants like Valvoline etc., fit in this? Many of these Sodium based oils use little to no Moly or Esters.
 
Joined
Nov 11, 2010
Messages
9,783
Location
Saskatoon canada
Interesting. I know molybdenum disulfide has the ability to plate moving parts. I don't think organic moly has this ability. Organic moly does leave a film on parts when the engine cools but doesn't plate per sey. Not how I understand how it works anyway. I could be wrong though.
 
Joined
Oct 24, 2011
Messages
961
Location
Ohio
Originally Posted By: CATERHAM
That was a very informative thread but I do have a question. As I understand it, AW/FM additives such as ZDDP and moly are sacrificial, in so much that during boundary/mixed lubrication what's plated onto metal substrates is depleted as it's worn off since they are no longer in a reusable form? How does the usefulness of the initial AW/FM additive concentrations of fresh oil play out as mileage is racked up on an engine? In other words, is there a set depletion rate for AW/FM additives? For example, take a typical energy conserving motor oil with 600 ppm of phosphorus and 100 ppm of some organic moly type. How effective are the AW/FM additives at 3,000 miles, 5,000 miles, 10,000 miles and 15,000 miles vs the virgin oil? And how would this oil when fresh compare in it's ability to protect vs an oil with higher additive levels that had already accumulated say 10,000 miles?
As long as the additives are present, and they are still active, then it makes no difference. But there is no uniform depletion rate as operating conditions play a big factor. This is why phosphorus retention has been such a focus in the GF-5 & GF-6 developments. However as explained below, depending on how the formula is put together the results could vary, especially if the moly becomes dehydrated. I'll have to look further into it, but I'm not sure if much comparison testing has been done on the effectiveness of the FM/AW on oils which are aged to various mileage intervals.
Quote:
I think someone once posted that organic moly has lost most of it's effectiveness by 5,000 miles?
That was me (several years ago): Moly content in oil typically comes from MoDTC (molybdenum dithiocarbamate) or MoDDP (molybdenum dithiophosphate) and it reacts with surface metals to form Molybdenum disulphide (MoS2) which is what creates the sacrificial wear layer. However over time the exposure of the molybdenum additives to oxygen changes the surface layers to Mo03 which is what is referred to as oxidative dehydration, this reaction takes time and so that is why the good fuel economy achievable with MoS2 in oils is hard to sustain over long service periods. (Basically oxygen + moly = very little wear protection). Water can also contribute to the deterioration of MoDTC and it can be difficult to see the effects of Moly continue beyond the 4000 mile mark. Using antioxidents can help prolong the effect that Moly has and so does our friendly ZDDP. So depending on what the additive package has blended with it Moly content (MoDTC) can still be very high but be basically inactive due to oxidative dehydration.
 
Joined
Oct 24, 2011
Messages
961
Location
Ohio
Originally Posted By: wemay
I have a question "...Esters, natural and synthetic fatty acids as well as some solid materials such as graphite and molybdenum disulfide are used for these purposes..."Where do the Sodum based lubricants like Valvoline etc., fit in this? Many of these Sodium based oils use little to no Moly or Esters.
The higher sodium add packs are typically referring to the detergents. This also has an impact on the types of FM/AW blends that are used. Molakule gave a feat explanation of this: Alternative Detergents "Sodium"
 
Joined
Apr 4, 2012
Messages
14,762
Location
Kendall, FL
Originally Posted By: Solarent
Originally Posted By: wemay
I have a question "...Esters, natural and synthetic fatty acids as well as some solid materials such as graphite and molybdenum disulfide are used for these purposes..."Where do the Sodum based lubricants like Valvoline etc., fit in this? Many of these Sodium based oils use little to no Moly or Esters.
The higher sodium add packs are typically referring to the detergents. This also has an impact on the types of FM/AW blends that are used. Molakule gave a feat explanation of this: Alternative Detergents "Sodium"
Perfect! Thank you.
 
Joined
Feb 25, 2008
Messages
316
Location
ONTARIO,CANADA
Anyone know what kind of moly is used in Redline Oil ?. I just finished an OCI using Redline 5w30 and the most noticeable reduction in wear was aluminum (pistons), compared to previous runs on other oils. I'm thinking the moly must have helped with this ?
 
Joined
Dec 30, 2006
Messages
25,855
Location
Dallas,Tx USA
Originally Posted By: JSRT4
Anyone know what kind of moly is used in Redline Oil ?. I just finished an OCI using Redline 5w30 and the most noticeable reduction in wear was aluminum (pistons), compared to previous runs on other oils. I'm thinking the moly must have helped with this ?
Post the UOA.
 
Joined
Aug 4, 2011
Messages
2,108
Location
Appleton, WI
In the article, it refers to Boron as "temperature-dependent". I was under the impression that Boron was the AW/EP additive that was not subject to heat activation, unlike the old standby of ZDDP. Is that correct?
 
Joined
Nov 5, 2014
Messages
18
Location
Texas
So based on what has been said here,the TGMO with its moly and ZDDP should display very little wear at 5000 mile intervals, correct? Thanks.
 
Top