I'm looking at this Castrol Syntec PDS, and I see that it gives viscosity in cSt at 100°C, and in SUS @ 210°F. Is SUS @ 210°F the same as cSt at 40°C?
Castrol data sheet question
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I'm not sure you asked the question correctly. cSt units are different than SUS. 100C. is approximately the same temp as 210 F. Thats the standard for these measurments.
The low temp viscosity is 100F for SUS and 40C for cSt. Forgive me if I stated the obvious or didn't understand your question.
The low temp viscosity is 100F for SUS and 40C for cSt. Forgive me if I stated the obvious or didn't understand your question.
I didn't understand the reasoning for the different ratings myself...almost like one in metric than the other in english, when all one wants is the high/low numbers in one unit. Seems like a goof to me, and thus am left without being able to compare viscosity vs. temperature relationships via 40 deg.c, 100 deg.c and then VI.
I don't know why the bother giving the SUS number either, even metriphobic troglidites are conversant in cSt these days.quote:
Originally posted by Curious Kid:
I didn't understand the reasoning for the different ratings myself...almost like one in metric than the other in english, when all one wants is the high/low numbers in one unit. Seems like a goof to me, and thus am left without being able to compare viscosity vs. temperature relationships via 40 deg.c, 100 deg.c and then VI.
It's unfortunate that the viscosity at 40C isn't given, but it's not a requirement to give it. It's just a nice bit of extra information.
They are different tests. SUS is a timed test, the time it takes the oil to go through a specific opening at the stated temperature. cSt is measured by an instument that has a disc that is rotated in the oil, and it measures the resistance to the rotation. It has been a while, but I think I have it correctly. You can look up the tests in ASTM. SUS stands for Saybolt Universal Seconds, cSt is abbreviation for centiStokes. Subject to memory errors......
You can look at the viscosity chart on this site and it gives a way to compare Saybolt and kinematic viscosity measurements....
http://www.bobistheoilguy.com/visc.html
http://www.bobistheoilguy.com/visc.html
Thanks for your help guys. I was hoping that someone would know how to translate those numbers to show the Syntec's viscosity in cSt at 40°C. So SUS and cSt aren't convertible like miles and kilometers?
BTW, does anyone know of any Castrol data sheets that show Syntec's viscosity at 40°C and 100°C?
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