Originally Posted By: miro
I know that is simple question but I cannot find the answer.
PAO base oil is know for purity /equal molecule length/.
Why the oil manufacture mix different viscosity synthetics oils?
Rules.
1. I will not judge who has the right answer. MolaKule is good contender for this job
2. Most likely there will be no single winner but many contributors for the final answer
Regards,
Miro
CT8 and Kira gave you the correct answer.
Here's the way it's done:
For a full synthetic base oil, low and high viscosity Group III to Group V bases oils are mixed in specific proportions to give a specific VI and to portray certain performance characteristics such as:
1. low temperature pumpability and flow,
2. high temperature film protection
3. High temp shear resistance
4. low volatility
5. oxidation resistance
In terms of base oils, today most motor oils are mixes of Group II through Group V base oils.
Here is something I have posted many times to show by example base oil mixes and perecentages:
Quote:
A base oil for a formulated PCMO is NOT one Single viscosity of base oil as I have explained many times here.
A formulator can take a binary blend (a blend of two base viscosities), or a ternary (a blend of three base viscosities), or an n-ary (a blend of "n" viscosities where n is any number) to make a base mix oil behave any way he desires.
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For example a 5W30
PAO 4 14%
PAO 20 56%
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A 5W40
PAO 4 20%
PAO 6 48%
PAO 65 2%
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A 10W30/30
PAO 6 25%
PAO 8 44%
PAO 150 1%
A 0W20
PAO 4 54.5%
PAO 6 15%
PAO 65 0.5%
Now don't get the idea this is typical or the ONLY way to get specific viscosities.