oil - question for GC

[oilman]

Ahhh now I see, that's where you are confused.

The lower the "w" number the better the cold weather performance.

5w is better than 10w and 10w is better than 15w etc.

Cheers
Simon

 

[sumplug]

Ahhh now I see, that's where you are confused.

The lower the "w" number the better the cold weather performance.

5w is better than 10w and 10w is better than 15w etc.

Cheers
Simon

simon.
you are not talking real world here. what about temp, pressure and shear rate. and the elastic properties of oil.
for a low friction, you need a thicker viscosity. pressure alters viscosity. shear rate is important. and the elastic properties is still not understood properly in the oil industry.
how an oil performs under all these conditions whether very cold weather or extreme hot whether, a 15/40 will out perform a 5/40. low friction is all important don't you agree?

 

[oilman]

Firstly at high temps the oil pressures will be the same as they have the same viscosity and viscosity has an effect on oil pressure. The higher the viscosity the higher the oil pressure. Oil pressure is resistance not flow.

You will have higher oil pressure with an sae 60 than with an sae 40.

Friction is also related to viscosity.

Low friction oils are 0w-20, 0w-30 etc, the thinner the oil at both ends of the range the lower the friction. That is why fuel economy oils for road cars are always 0w-30 and 5w-30.

Cheers
Simon

 

[sumplug]

Firstly at high temps the oil pressures will be the same as they have the same viscosity and viscosity has an effect on oil pressure. The higher the viscosity the higher the oil pressure. Oil pressure is resistance not flow.

You will have higher oil pressure with an sae 60 than with an sae 40.

Friction is also related to viscosity.

Low friction oils are 0w-20, 0w-30 etc, the thinner the oil at both ends of the range the lower the friction. That is why fuel economy oils for road cars are always 0w-30 and 5w-30.

Cheers
Simon

well according to shell;-
"The valve train operates in a mixed boundary lubrication regime, which means that lower friction can only be obtained with thicker lubricants"
in high pressure situations, the thin oil will be pressed out and the thickness layer between metals is vastly reduced causing higher friction.

 

[pinin__prestatyn]

Ah sumpy, doing what you know best! You love it don't you

 

[sumplug]

Ah sumpy, doing what you know best! You love it don't you

a friend of mine runs spur petroleum who blend oil and sells it retail. he knows what he's talkimg about. but here is the shell related link to read and consume for you.
btw, i don't talk crap, only facts.
http://physicsweb.org/articles/world/15/2/7

 

[HP]

well according to shell;-
"The valve train operates in a mixed boundary lubrication regime, which means that lower friction can only be obtained with thicker lubricants"
in high pressure situations, the thin oil will be pressed out and the thickness layer between metals is vastly reduced causing higher friction.

This is the part we never got an explanation for previously, not being evil but am genuinely interested to know.

 

[sumplug]

This is the part we never got an explanation for previously, not being evil but am genuinely interested to know.

see above link.