Originally Posted By: Solarent
Originally Posted By: Virtus_Probi
Hmmm...they didn't experiment with varying the magnesium levels?
Seems like M1 and Castrol keep a reasonable TBN by adding magnesium when they drop the calcium. Mobil 1 ESP just cuts the calcium, adds no magnesium, and lives with a lower TBN with the benefit of a SAPS lower than M1 (I think).
We really can't know exactly what the formulators did. Here on BITOG we compare VOA and PQIA data and assume we know what kinds of detergents/dispersants are being used. In reality - while a lot of things can be inferred by these kinds of reports oil formulas are much more complex than that.
One thing is certain - if it was as easy as substituting a magnesium detergent for a calcium one then everyone would have done it and there would be no need for developing a new LSPI test for the next category upgrade. There is still lots to learn and as TGDI engines take over the market over the next 5 years, I feel like there are still lots to learn that we probably haven't even thought about yet.
You are absolutely right...I saw that M1 and Castrol had lower calcium levels than other 5W30 synths with good TBNs and guessed that their higher magnesium levels explained that. It's just a basically uninformed guess, but I did peek at the periodic table to see that Ca and Mg are in the same column (which is an indicator that they might have similar chemical properties).
Should be put in the same category as my thoughts about Chinese airstrips in the South China Sea and the search for the Higgs boson, the rambling of a dilettante!
;^)
