Originally Posted By: 45ACP
Originally Posted By: CATERHAM
I dont understand the blending. You are assuming that EVERY part of said blended oils will be the same, this resulting in the higher VIs and such.
Why not just use one oil that is good?
Because it's hard (or very expensive) to find one oil that good for every application.
In the case of the M1 racing oils, if you can get a deal on them they will raise the ZDDP level of every SM/SN oil if you need a higher level while improving the oils VI with some naturally high VI basestocks.
Of course high VI's benefit an engine; it's the holy grail in motor oil formulation.
When it comes to 30wt oils there are very few with VIs over 180 but their are readily available 0W-20s and 0W-40s with very high VIs so one can make their own 180 or even 190 VI 0w30 if you want.