Originally Posted By: JHZR2
Is it me or is that P low? Could have sworn I was looking at a gear oil uoa the other day that was a few thousand ppm higher!
Some formulators still use an older S-P gear lube additive from commercial additive suppliers that have sometimes thousands of ppm of phosphorus.
I use a new multi-functional phosphate ester as the primary (High Tem) EP agent which results in a lower phos ppm and a commercial (Low Temp) Potassium-Borate add as a secondary EP additive.
This combo yields about 50 ppm of iron wear verses 350 ppm compared to other gear lubes using the same SAE grade, differential loading and mileage.
Originally Posted By: MolaKule from 10/08/03
EP Additive Chemistry
Here is some data averaged over 3 conventional (mineral) Hypoid GL-5 gear oils of SAE 90 weight as to range of additives:
As we stated before, the additive package may occupy from 3.5% to 10% by weight of each quart of oil.
KV - 17.42 to 18.24 (100 C)
VI - 98-101
Additive EP Elements (% by weight)
Sulfur - 2.72 to 2.93%
Phosphorous - 0.11% to 0.12%
Chlorine - 0.02%
Nitrogen - 0.08 to 0.09%
Borons – 0.5% TO 2%.
The Borons and Calcium carbonates are slowly replacing the chlorines.
Now for certain oils, you might see additional AW/EP components such as Moly and Antimony in less than 1%-3% concentrations.
Gear Tribology and Lubrication II
