What exactly are friction modifiers?

Pennzoil motor oil
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aquariuscsm

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I was reading/searching through some old and new posts trying to understand friction modifiers and their role in motor oils. I always search before posting,but the fm stuff I can`t really seem to understand. There was a thread in the HDEO section talking about 15W40 gas/diesel oils containg no or less fm`s then PCMO`s.

What`s the difference between oils with none/less fm`s vs an oil with more fm`s? I see where 15W40 HDEO`s are very popular and recommended. RP even recommended their 15W40 for my car,which I use and absolutely love! Excellent oil!!!!!

Would an HDEO with less fm`s be more "slick" or "slippery" per se than a PCMO with more fm`s,or vice versa?
 
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I am a layman , not an oil engineer. Nor do I play one on TV.
My take is that 'friction modifiers' are not exactly Anti Wear [AW] or Extreme Pressure [EP] additives in engine oil.
Friction modifiers seem to be in transmission and gear lubes. They either slip and let hypoid gears slide easier, or grab and let synchros bite more.

A cam chain or a cam/lifter can be very highly loaded in an engine. The oil additives in a HDEO can help with friction and wear on those localized spots.
But to call them friction modifiers? I dunno...
 
Originally Posted By: Big Jim
Friction modifiers make the oil more slippery.



So a pcmo has more fm`s than an hdeo,right? So is a pcmo more slippery than an hdeo?
 
Originally Posted By: aquariuscsm
Originally Posted By: Big Jim
Friction modifiers make the oil more slippery.



So a pcmo has more fm`s than an hdeo,right? So is a pcmo more slippery than an hdeo?


If the pcmo is an energy conserving one then by definition the answer is almost certainly yes, if it not energy conserving, maybe not.
Of course you first must quantify the term slippery, which Molecule will say is not quantified therefore a poor terminology.
You would also have to state whether you are talking about in the hydrodynamic regime or in the boundary lubrication area.
 
I look at it like a mucous layer (bear with me, it's in Gary-speak
grin2.gif
). Mixed/co-regime
 
Friction modifiers are a sacrificial, first line of defense, anti wear. Lets take an oil with ZDDP and a good dose of friction modifiers. The phosphorus will attach to the journal and bearing. If the oil film is breached for whatever reason, then phosphorus rubs against phosphorus to protect the bearings and journal. However, phosphorus against phosphorus is a high friction surface. It generates heat and consumes energy/power.

Now the friction modifiers will attach to the phosphorus on the journal and the bearing. I have heard FM describes like fine hair/whiskers. If the film is beginning to breach, you will have FM against FM. They are sacrificial and shear away with very little friction, thus the name friction modifiers. If the breach is severe, then back to phosphorus against phosphorus.

Again, FM are a first line defense, very low friction, generates little heat, consumes little energy/power. Some them as a near miss protection. I like all the FM I can get in an oil.
 
I was watching a program about motor oil production and saw how they at the FM. It's crazy. It comes in huge blocks that look like lard, and they are solid. Once added to the oil, they are heated up and it is dispersed throughout the concoction.
Any of you ever seen what I'm talking about?
 
Originally Posted By: aquariuscsm
I was reading/searching through some old and new posts trying to understand friction modifiers and their role in motor oils. I always search before posting,but the fm stuff I can`t really seem to understand. There was a thread in the HDEO section talking about 15W40 gas/diesel oils containg no or less fm`s then PCMO`s.

What`s the difference between oils with none/less fm`s vs an oil with more fm`s? I see where 15W40 HDEO`s are very popular and recommended. RP even recommended their 15W40 for my car,which I use and absolutely love! Excellent oil!!!!!

Would an HDEO with less fm`s be more "slick" or "slippery" per se than a PCMO with more fm`s,or vice versa?


This is good, easy to understand:

https://bobistheoilguy.com/forums/threads/friction-reducers-and-aw-additives.57845/
 
So,looking at the formulas and ignoring the weight,which oil out of RP 15W50 and 20W50 would give the best protection (if you drive it like ya stole it)? I have a couple of cases of 20W50,but I really love their 15W40 as well. Are they the same basic formula,just a weight difference? Or does the 15W40,being an HDEO,offer more/less protection than their PCMO 20W50?

I guess I`m having a bit of trouble differentiating the performance/protection between a PCMO and an HDEO.
 
I know absolutely nothing about royal Purple oils except from threads on here. I don't know their base oil, their add pack, or anything. If you follow the link above back, it goes into why HDEO use little to no FM. Once I learned they had little/no, I immediately lost interest and ceased to search more about them.
21.gif


I use a 15W-50 synthetic, SM, high FM, high ZDDP in everything and have for 19 years, near 2,000,000 miles combined.
 
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Originally Posted By: strombony
I was watching a program about motor oil production and saw how they at the FM. It's crazy. It comes in huge blocks that look like lard, and they are solid. Once added to the oil, they are heated up and it is dispersed throughout the concoction.
Any of you ever seen what I'm talking about?

That was VII.
 
Originally Posted By: FrankN4
Originally Posted By: aquariuscsm
I was reading/searching through some old and new posts trying to understand friction modifiers and their role in motor oils. I always search before posting,but the fm stuff I can`t really seem to understand. There was a thread in the HDEO section talking about 15W40 gas/diesel oils containg no or less fm`s then PCMO`s.

What`s the difference between oils with none/less fm`s vs an oil with more fm`s? I see where 15W40 HDEO`s are very popular and recommended. RP even recommended their 15W40 for my car,which I use and absolutely love! Excellent oil!!!!!

Would an HDEO with less fm`s be more "slick" or "slippery" per se than a PCMO with more fm`s,or vice versa?


This is good, easy to understand:

https://bobistheoilguy.com/forums/threads/friction-reducers-and-aw-additives.57845/


From the link (the benefit I like to think is most important):

Quote:
Friction reducers can also reduce the shearing action of the fluid, thus leading to better MPG and less energy dissipated in the oil.
 
Originally Posted By: FrankN4
I know absolutely nothing about royal Purple oils except from threads on here. I don't know their base oil, their add pack, or anything. If you follow the link above back, it goes into why HDEO use little to no FM. Once I learned they had little/no, I immediately lost interest and ceased to search more about them.
21.gif


I use a 15W-50 synthetic, SM, high FM, high ZDDP in everything and have for 19 years, near 2,000,000 miles combined.



Only thing I know about Royal Purple (from reading the UOA`s here) is that they`re a PAO group IV base stock with an ester group V additive (Synerlec). They seem to do really good in the UOA`s as to holding up and such. My car runs extremely well and smooth on RP`s oils. I`ve only used 15W40 and 20W50 (their street oils).

I may go ahead and fill my car up with the 20W50 till the fall,then fill her up with the 15W40 for the fall/winter fill.
 
Originally Posted By: aquariuscsm
So is an HDEO *more slippery* than a PCMO? Man,the science behind oil is confusing,huh!



Quote:
Friction reducers can also reduce the shearing action of the fluid, thus leading to better MPG and less energy dissipated in the oil.

I don't know why I missed that, but that would be a top consideration.

If I understand your meaning of "more slippery", and I may not, then the answer is no. PCMO would likely have considerably more FM including MOLY. Up until the instant the boundary lubrication begins to break, I doubt there is any difference in "slipperiness" between PCMO and HDEO.

Also, not all HDEO's are diesel formulations. Look at the specks on Amsoil 5W-40, Mobil 1 10w30 HM, Mobil 1 10W-40 HM, Mobil 1 15W-50, Valvoline full synthetic Valvoline MaxLife 10w30, Valvoline full synthetic 10W/15W-40 HST. All these run HTHS of over 3.5 up to about 4.5.
 
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