what the heck? i just forgot how to read an msds?

[cryptokid]

i was searchin pennzoils msds for their 10w30 and 10w40 dino oils.

it shows the 10w30 oil having a viscosity of 83.3 cst at 40C. the 10w40 shows a viscosity of 109.4 cst at 40c.

i look on bobs oil viscosity chart here http://www.bobistheoilguy.com/visc.html

and this doesnt make any sence!?! how can either of these oils have a viscosity of 83 to 109 at 40c and still be considered a 10w?
how come the last time i looked at pennzoils msds everything made sence but this time these oils appear to be not right at all! am i having a brain **** or what?

LoL **** is a censored word!

[ July 03, 2004, 12:53 AM: Message edited by: cryptokid ]

 

[cweed]

here's something else to freak the **** out of you, M1 T&SUV 5W-40 is 102 cst @ 40! lol

Those ratings refer more closely to the second number than the first because 40c is not exactly a cold temp

so 90@40c is ok for a 30 wt while 109@40c is alright for 40 wt that flows like a 10 at low low temps, hence those numbers for the 10W-30 and 10W-40

But I think its best to look at the @ 100c number, its more of what the oil experiences in your engine and this number you can associate fully with the second wt number, like 30 or 40 in your case.

[ July 03, 2004, 01:34 AM: Message edited by: cweed ]

 

[cryptokid]

this whole system is so messed up. hows a commoner suppose to understand any of this 10w crap.
why cant they label things clearly on the bottle.
this is one thing i really hate about oils, the 30w can be amlost a 40 and still be a 30 (like gc) so where is 31 through 39?
ur mobil 5w40 is thicker at 40c then pennzoil 10w30. thats stupid.
why are oils even tested at 40c? why not a more realistic number like 20c
or maybe from -30c to 200c in 10 degree increments would be really, really nice using iso measurments and no xxwxx crap.

all i really wanted to know was what viscosity would a monograde oil with a viscosity of 30@ 100c be at 20c. i tried to figures it out loking at the other oil viscositys but its too much trouble for my simple mind.

[ July 03, 2004, 02:00 AM: Message edited by: cryptokid ]

 

[rugerman1]

Try this VI calculator HERE

I had to Google and find this one.The one I used in the past is no longer available.

Mark

[ July 03, 2004, 12:11 PM: Message edited by: rugerman1 ]

 

[FowVay]

Remember that when they manufacture a oil they have a cold flow characteristic in mind. They start off at this point. The fluids are measured dynamically and not kinematically. This is the reason that the cold temperature viscosity is given in centipoise instead of centistokes.

A 10W anything is formulated to deliver 7000 centipoise at -25ºC. This is torque measurement which reflects the amount of energy needed to essentially spin a flapper in a cup of oil when it's cold.

The numbers printed on a bottle of oil don't really have anything to do with the cold flow properties of the oil. This is why you have 5W-40's that are thicker at 40ºC than is a 10W-30. It doesn't make much sense until you sit down and understand the differences between kinematic and dynamic viscosities and linear grading.

I don't know if this tidbit of data is on BITOG but here's quick run-down of target viscosities:

0W oils = 6200 cP's @ -35ºC
5W oils = 6600 cP's @ -30ºC
10W oils= 7000 cP's @ -25ºC
15W oils= 7000 cP's @ -20ºC
20W oils= 9500 cP's @ -15ºC
25W oils= 13000cP's @ -10ºC

Everything from this point on is modified through the use of very well resonding base stocks and modifiers to achieve the desired thickness.