[hate_romania]

SAE Grade 5W-20
Viscosity, ASTM D 445
cSt @ 40º C 48.3
cSt @ 100º C 8.8
Viscosity Index, ASTM D 2270 163
Sulfated Ash, wt%, ASTM D 874 1.0
HTHS Viscosity, mPa·s @ 150ºC ASTM D 4683 2.62
Pour Point, ºC, ASTM D 97 -47
Flash Point, ºC, ASTM D 92 228
Density @15º C kg/l, ASTM D 4052 0.80


what are all of this, and how each one of them afects the oil, and in a ideall word how the numbers should be?

thx for your time

 

[nova]

Best place to ask that is BITOG.
You'll have to do some homework & maybe lose a little flesh but Don't be afraid...

 

[HouRman]

It's 5W-20 oil that is the right viscosity for our cars.

I dunno if using those stats are as valuable as actual engine oil analysis numbers.

 

[animal4l]

5W-20 = SAE weight grade designation: 5 weight when warm, 20 weight when cold

Viscosity = how "runny" the oil is. 48.3 cSt (centistokes) at 40°C, 8.8 cSt at 100°C, tested per ASTM D 445

Viscosity Index = ASTM rating on how the viscosity changes with temperature, tested per ASTM D 2270

Sulfated Ash = ? (I think it's a measure of how many sulfates are commonly found in the oil)

HTHS Viscosity = High Temp High Speed viscosity, looks like it's measured in mPa s @ 150 °C

Pour point = minimum temperature oil can be poured (not like molasses)

Flash point = minimum temperature oil can be ignited, given presence of oxygen and ignition source

Density = mass per volume (multiply density by volume to get total mass of oil)

These are all just physical properties of the oil. There is no "ideal" values to these numbers... the engineers just design the lubrication system to the oil properties. Engine oil analysis numbers are more valuable because they tell how "used" the oil is, and how close they are to the given specifications.

 

[seventynine]

I read on BITOG, and please correct it if im off, that when viscosity is greater than 10cSt, the oil puts wear on the engine. Hence, when u start ur engine, the cold (40deg C) oil with viscosity around 40-50cSt puts wear on ur engine. And this another reason why synthetic oil is recommended, because it has somewhat lower cSt numbers than conventional oil, making it better at startup.

 

[D Bone]

[quote author=animal4l link=topic=66533.msg1142667#msg1142667 date=1168451139]
5W-20 = SAE weight grade designation: 5 weight when warm, 20 weight when cold[/b
[/quote]

You're incorrect here. 5w-20 means that the oil will flow in the winter like a 5 weight oil ("5w"). "W" actually stands for "winter rating". The oil will act like a 20 weight oil when hot.

You had your explanation of the hot and cold SAE ratings reversed.

BITOG is a great source for info http://theoildrop.server101.com/forums/ubbthreads.php



Darryl

 

[animal4l]

Doh! Got 'em switched! I was just working off of my head... Thanks for the correction!