Limited Slip Adds/Oils. Fucntionality.

[Lowflyer]

Hi guys (and gals)

For first, and one time, sorry for my gruesome English. Its less my fault, rather of the education system... But I give always my best. Hope this works good enough (dont call me Yoda please )

Ok. Now my question, corresponding to thread subject.
(I have WELL search for it, but NOT FOUND threads with clear answers to my question. Sorry.)

LimitedSlip (LS) adds and LSD gear oils. Technical functionality of LS supplements.
I dont understand this, WHEN I ponder above

The necessity is clear, usage is clear and design of a few types of diffs is also comprehensible. Ok, what I have dont understand:

If you need LS adds in diff oil, and you dont have it, you have: chatter or humming and so forth, from the LS part of LSD. Ok, clear matter.
FOR ME (so far), this means, the diff locking to soon and/or to much. You also need LS adds in the oil, but it be called: limited slip.
If you have for example humming ,you have (for me, but I am still not enlightened) too little slip. LSD lock to soon/to hard. Or not?

Mean, LS adds, as friction modifier, not limited but increase the "slipness" of the diff oil?? Or I bark the wrong three?
As already stated, this make me confused.

Background.
I have still a little bottle of OLD and "legendary" (?) Sturaco 7098 diff/gear additive. And If "you" look on the site for newer Sturaco, 7098, they say:
" Sturaco 7098 is a friction modifier to supplement sulfur-phosphorous gear oil additives for limited-slip performance"

And on the another hand, for:
"Manual transaxles: 3% - 5%, Engine oil for noise reduction: 1 % - 2%, Universal tractor fluids: 2% - 4%"
Nothing about LSD. And I known, also ZF (german gear company) use 7098 as "FM 1992 KS", as additive. Officially. In automatic transmissions…
https://www.houghtonintl.com/de/products/sturaco%C2%AE-7098

Old PDF from Stuart (over Google, grmpf)
https://www.google.de/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&ved=2ahUKEwjs6MO1u8bkAhVqyaYKHUaTCj4QFjAEegQIBBAC&url=https%3A%2F%2Fwww.4x4brasil.com.br%2Fforum%2Fattachments%2Fford%2F84045d1181514484-aditivo-modificador-de-atrito-sturaco-7098-a-sturaco-7098.pdf&usg=AOvVaw3_GHy-Q8Gif2zL8CEZqByc

But, I have no LS diff and no ZF gear parts. I have manual transmission, angle gear and no-LS diff. I only thought, I can increase efficiency of my gears for 0.0x%

if I add 1% Sturaco.

But-2, you MAY use 1% Sturaco 7098 in engine oils, but never ever for example… Penrite Limslip Additive

With the same specs like Sturaco

, (go to "Specifications")
https://penriteoil.com.au/products/limslip-additive
"Most LSD friction modifiers are of a standard formulation."

https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/285700/Sturaco_7098_LSD_friction_modi

regards, Lowflyer

 

[DuckRyder]

Your english ain't that bad...

So, in a nutshell you are wondering about the semantics of calling the additive "limited slip" when is actually "increased slip" and if said additive might perhaps make a manual transmission more efficient through decreasing friction, If I understand you correctly.

To point one, I believe it came to be called "limited slip additive" because it is for limited slip differentials vs function within same...

To point two, I would worry the synchronizers might not like the friction modifier...

 

[Lowflyer]

Ok, the one is a name assignment. But my punchline question is: Make LS friction modifier, oils more or less "slippery"?

edit:
Wow... 100 hits, 1 answer

 

[Oro_O]

The additives make the friction surfaces of the discs (not gears) slip MORE. Molakule had a post a few months ago on the chemical intricacies of this.

Too much additive, they act like an open diff. Too little, they lock-up too soon and you get the banging on turns indicative of worn or LSD's with too little additive.

I do not think using it in a non-lsd application will affect it. The interaction with the clutch material is where it comes into play; and not affecting gear surfaces. Again, *I think,* Molakule or more knowledgeable folks can be definitive.

 

[MolaKule]

Originally Posted by Lowflyer
Ok, the one is a name assignment. But my punchline question is: Make LS friction modifier, oils more or less "slippery"?

edit:
Wow... 100 hits, 1 answer

It doesn't make it more or less slippery.

Quote
The FM chemical compound modifies (changes) the Coefficient of Friction (COF) between the respective surfaces "on-the-fly" depending on the relative speeds of the rotating components and the applied pressure forces. That is, it decreases OR increases friction depending on the relative speeds of the rotating components and the applied pressure forces in order to prevent Stick-Slip which causes shudder.

 

[DuckRyder]

Originally Posted by Or
The additives make the friction surfaces of the discs (not gears) slip MORE. ....


Correct.

the type of LS that needs this additive is a clutch type which has fiber plates - think automatic transmission clutch pack...

 

[Lowflyer]

Ok. It doesn't make oil more or less slippery and not affecting gear surfaces -> Groked.
Many thanks for your answers.

But it generated a one supplementary question. We have still the Sturaco PDF - samey whether older from Stuart or newer from Houghton - with assertions for 1-2% usage in engines and 3-5% in manual transmissions. For what? Whereby?

With a cocktail, which shall to act solely with clutch type plates

Or 7098 was... dadecated than another and than newer LS adds? In datasheet of 7199, they find nothing (more) about engines or manuall transmissions (but above, it dont rankles your Viton

)

 

[MolaKule]

If you are referring to how much to add to a differential my suggestion has always been:

Add 1/4 of the package to the differential lube. Do figure 8's in an empty parking lot with your window rolled down.

Did you hear any chattering or grinding sound?

If yes, add another 1/4 package and do the same.

Once the chattering has gone, cease adding. That is, add only enough to stop chattering.

Most people overdose using this stuff.

Certain types of Limited Slip Differentials may contain actual specialized clutch plates or sintered metal 'cone" type clutch mechanisms.

 

[Lowflyer]

Nope. Thx but this was not the punchline. I add never more than 2% of, no matter what, additives.
Mostly, for better sleep

Not for necessity.

The point is add to enigne oils, diffs without LS and transmissions (as I wrote)

 

[MolaKule]

I have no idea what "punchline" means,

Your question still isn't clear but maybe this will help:

https://www.bobistheoilguy.com/foru...53181/friction-modifiers-fms#Post5153181

Sturaco Additives are LSD chemistry for driveline Differentials.

And no, you cannot mix different friction modifiers for different applications.

Each friction modifier has a unique chemistry for each application.

 

[Lowflyer]

thx.