Quote:
Originally Posted by Joe@Amsoil
Wow there is definitely a lot being said in here and all over the board as far as opinions. There is a lot of mis-information being passed around.
First thing that needs to be clarified is the statement "When oil is colder its thicker". This is a false statement. Going back to the basics, oil is rated by viscosity which is the oil's resistance to flow or simply put an oil's speed of flow as measured through a device known as a viscometer. The higher viscosity of an oil, the slower it will flow ie thicker. Looking at the stock fill for the BRZ its a 0w-20 oil. This means a 0 viscosity at cold operating temperatures and 20 viscosity at operating temps of 210*. On cold starts you need oil to flow quicker ie low viscosity ie THINNER oil to help reduce dry run time. So that being said.. when oil is a 0w-20 its THINNER at colder temps
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This is entirely false!
As Skullworks correctly said 0w-20 means that the oil acts like a mono weight 0w grade when cold and a mono weight 20 when hot ie the viscosity changes less with temperature than a straight 0W grade (which would be too thin when hot).
This is due to the viscosity modifiers mixed into the oil which are long chain molecules that ball up at low temperatures allowing the oil to flow more freely but then uncoil at higher temperatures and tangle together increasing the effective viscosity of the oil.
Go and read this
http://www.ideas4ag-ed.com/uploads/3..._viscosity.pdf
I am quite frankly shocked that a representative from a supposedly well respected oil manufacturer can't get his facts correct.