Interesting Oil Facts
Discussion
At which temperature does an oil flow better?
There is no temperature where oil suddenly starts to flow better.
A 10W/40 for example will flow between -25C and 100C or more, but there is some difference in the rate of flow! (True viscosity at -25C is about 7000 Centistoke(cSt) units, dropping to 14 at 100C. ‘Viscosity’ is really just another name for ‘rate of flow’.)
The correct question is at what (sump) temperature is an oil at a viscosity that suits a modern high-RPM engine? Present day designs are happy on an oil viscosity of 10 to 15 cSt. (But many are OK on less than 10.) 30cSt is too high at high RPM. It can lead to foaming, air entrainment and cavitation.
Temp. for 30cSt (DegC)..........Temp. for 15cSt ............Temp. for 10cSt
5W/40.........71.............................90.................................117
10W/40.......70.............................99.................................118
10W/50.......80............................109................................130
10W/60.......89............................119................................142
As you will see from the above table a 5W/40 or a 10W/40 is perfectly adequate for all engines except those that run unusually high temperatures (120degC plus)
Cheers
The Opie Oils Team
There is no temperature where oil suddenly starts to flow better.
A 10W/40 for example will flow between -25C and 100C or more, but there is some difference in the rate of flow! (True viscosity at -25C is about 7000 Centistoke(cSt) units, dropping to 14 at 100C. ‘Viscosity’ is really just another name for ‘rate of flow’.)
The correct question is at what (sump) temperature is an oil at a viscosity that suits a modern high-RPM engine? Present day designs are happy on an oil viscosity of 10 to 15 cSt. (But many are OK on less than 10.) 30cSt is too high at high RPM. It can lead to foaming, air entrainment and cavitation.
Temp. for 30cSt (DegC)..........Temp. for 15cSt ............Temp. for 10cSt
5W/40.........71.............................90.................................117
10W/40.......70.............................99.................................118
10W/50.......80............................109................................130
10W/60.......89............................119................................142
As you will see from the above table a 5W/40 or a 10W/40 is perfectly adequate for all engines except those that run unusually high temperatures (120degC plus)
Cheers
The Opie Oils Team
350Matt said:
Hang on chaps
What about the older engines which need the thick stuff to maintain oil pressure, all very well to say you'll reduce the windage losses. But if its jetting out of the sides of the shells, the bearings won't be too happy
Matt
He did say What about the older engines which need the thick stuff to maintain oil pressure, all very well to say you'll reduce the windage losses. But if its jetting out of the sides of the shells, the bearings won't be too happy
Matt
opie said:
suits a modern high-RPM engine
Edited by jimmystratos on Saturday 26th April 23:14
stewie732 said:
so am I stupid for using 0w 40 synthetic mobil on my type r?
No your Honda Screamer will love the stuff,its also more oil than Honda specify anyways and your engine will thank you for it with a longer service life,just change it once a year or 6k approx ex Honda technician
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