oil - question for GC
- Thread starter Hellcat
- Start date
Currently reading:
oil - question for GC
sumplug
Established member
simon.oilman said:
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
New member
- Joined
- Nov 18, 2004
- Messages
- 108
- Points
- 26
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
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
Established member
well according to shell;-oilman said:
"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.
Ah sumpy, doing what you know best! You love it don't you 
sumplug
Established member
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.pinin__prestatyn said:Ah sumpy, doing what you know best! You love it don't you
btw, i don't talk crap, only facts.
http://physicsweb.org/articles/world/15/2/7
sumplug said:
This is the part we never got an explanation for previously, not being evil but am genuinely interested to know.
sumplug
Established member
see above link.fixitagaintomorrow said:
