How do ashless AW additives work?

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Jun 10, 2002
Molakule has graciously given great descriptions on the operation of the common ash based or metallic AW addtives, such as MoDTC, ZDDP, SbDTC, Boron, overbased calcium, etc. And we now have a pretty clear idea how they work.

But, how do the ashless AW additives work? They may have been briefly mentioned as to the fact that they exist, but we have never discussed what they are and how they work. We have discusssed ashless FM and antioxidants but not AW. Been wondering for a while but what also prompted more interest was a quote on Valvoline's website regarding the VR1 oil: "New ashless anti-wear additives combined with ZDDP provide ultimate wear protection"

If anyone has any info for discussion, please share. Otherwise, hopefully Molakule will chime in.
I think we're going to/are seeing a trend towards the increase use of ashless additives, like with the new diesel rated lubricants IIRC and there low emissions formulations.

I'm very much in the elementary level concerning additive interactive properties, but the information would be interesting none the less.

Take care.
Well Fuchs Titan GT1 0W20 is a completely ashless oil (zero ZDDP), intended for racing! Whatever AW agents their using must be pretty top notch...
""But, how do the ashless AW additives work?""

Same as metallic additives but they cost more and sometime treat rate is higher than "conventional Stuff"
I know, I'd like to give it a shot, however, there is no distributor for it in the US, and I'm not too keen about having it shipped from Signapore. Otherwise, everything that I've heard or read about this oil is that it is fantastic.
Ashless AW and EP additives are generally aminic compounds of phosphorus, phosphoruous and sulfur, nitrogenated sulfur compounds, boron esters, polycarboxylates, triglycols, and similar compounds.

The dipenylamines are generally used as ashless antioxidants.

AW additives form films with the base metals to guard against wear in the mixed and boundary lubrication regime.
Hey there Mola, thanks for that explanation. Do you prefer ashless to standard AW additives, or does it depend on what exactly you want the final formulation and composition levels of the oils to do first?
"It depend(s) on what exactly you want the final formulation and composition levels of the oils to do first"
Basically here are some "general" rules of thumb:

1. Reduce ash-type additives in racing, 2-cycle, and natural and LPG oils if possible.
2. Increase ash-type AW additives in racing and HM oils until newer ashless AW become more prevelent.
3. Increase ashless-type AW as ash-type AW additives are reduced in content.

In some cases, multifunctinal ash-containing anti-oxidant/AW additives are needed in certain lubricants where
lower cost and proven additive technology are required.

Again, the exact formulation is developed for the specific application.
Thanks MolaKule, as always.

Why should ash-type additives be reduced in racing oils? Usually they have had high levels of ash-type additives...maybe because it's the cheaper, easier route. I can see the negative being ash-deposits increasing chance of detonation since they heat up very quickly (hot spots).
I understand what you are saying MolaKule, but in reading it, it almost sounds like an oxymoron. Increase yet reduce. I guess in the long run it depends on the usual answer...$$$$ Just how much of it are you willing to use in the formulation in order to come up with your desired levels of protection and ability and weigh in exactly how much your clientelle is willing to pay.

Guess I would be the cat's meow for a gung ho R & D company, eh?!?!
Just a WAG, but think in generalization #1 he's referring to ash from the detergent additives. #2 refers to AW add's ?

Another WAG. Many modern race engines don't use an oil control ring so there is more chance of oil into the combustion chamber.
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