Originally Posted By: dave1251
Originally Posted By: volk06
Yes,
The older formulation will have a higher dose of calcium (2200ppm). The newer versions uses 1/2 calcium and 1/2 magnestium, (1000ppm).
Performance wise it seems the SN version loses its TBN quicker then the SM and has a lower starting TBN.
From the VOA's I have seen you would be mistaken. The calcium content you have stated is in line. But the magnesium is way off there is only traces of magnesium in SM Mobil 1 15w50.
The SN formulation indeed has about 1000PPM but also about 650PPM of magnesium.
TBN for the SN is lower. But as far as TBN retention compared between the two? I do not have enough UOA data but I am willing to bet if someone used the SM version for a 10K OCI with normal spirited driving I am willing to bet the SN version will yield comparable results.
I believe you would be mistaken as you did not read what I posted. I did not say the SM had any magnesium in it, only the newer version (SN) had MG. I've seen the results for the magnesium vary from 600-1000ppm depending on the VOA/UOA (could have been residual). Therefore the reason why I said 1/2 CA, 1/2 MG at around 1000ppm. I realize that was a bit optimistic now and off, actually varying between 500-700ppm MG. Note that this is not the only site that has uoa on it, a few performance forums have guys that do uoa as well.
This uoa has 2 Mobil 1 Extended Performance SN and the rest Mobil 1 Extended Performance SM, the results do vary from uoa to uoa but if you look at the miles, the SM TBN held its retention better in this engine and application.
https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2681083#Post2681083
