VSOT viscosity at 40C?

[CATERHAM]

According to Valvoline it is 100 cSt @ 100C.
Anyone got any Idea what it is at 40C?
If I had to guess, would 1000 cSt be far off?
The reason is to get a handle on the effect on an oil at low temps' using a viscosity calculator.

Peter

 

[Pablo]

my guess = thick

(1000 cSt might be a bit high, though. 250-500?)

Dang that's viscous!

Ask Valvoline.

It's diluted pretty well even if you use the whole container.

 

[vizvo]

You could assume 1000 cSt as a "worst" case figure for the sake of your calculations, and then see if it yields numbers within your target limits.

I guess you're going to use the Shell Viscosity Index Calculator.

 

[CATERHAM]

I did email Valvoline - no response.
I figure 1000 cSt based on Shaeffers additive #132 being from memory approx' 250 @100C and 2300 @40C.
I want to determine the effect on CC before I add it during the winter.

Thanks for the reply .

Peter

 

[CATERHAM]

Yes Vizvo that's what I was thinking.
BTW,how familiar are you with the Shell Calculator? One can assume that the further outside the 40C to 100C range you "extrapolate" the less reliable the estimated viscosity will be. For example, calculations for -20C can be significantly off. Case in point- Amsoil 0W30:
40C .... 57 cSt
100C ... 11.1 cSt
-35C ... 5520 CC

The calculator produces a vis' @ -20C of 1429 cSt which is incrediable low; even lower than M1 0W20 which is about 1720 @ -20C which is probabily one of the the lightest motor oils on the market. Based on other oils Amsoil should be around 2500 cSt @ -20C.

Peter

 

[vizvo]

Hello CATERHAM. I believe you are right. Extrapolating beyond the bounds of known data points is always iffy. And it seems apparent that viscosity calculations behave somewhat differently as viscosity increases.

For example, the formula for converting SUS to cSt viscosity when SUS is less than or equal to 100 is:

code:

---

cSt = 0.226T - (195/T )



where T = SUS viscosity less than or equal to 100.

---

However, as viscosity increases to SUS being greater than 100, the conversion formula has to be modified:

code:

---

cSt = 0.220T - (135/T )



where T = SUS viscosity greater than 100.

---

My guess is that the Shell viscosity calculator may not compensate for thicker viscosity, at least beyond the data points. Although the above formulas aren't directly applicable to your problem, they may provide some insight as to what is going on.