GTX 5w20, viscosity at 40c?

[Patman]

Does anyone know the viscosity at 40c of GTX 5w20? Castrol only lists the 100c specs on their website.

I'm just curious to see how their 5w20 compares to other 5w20s at 40c. I know they are one of the thicker 20 weights, as it checks in at 9.1 cst at 100c.

 

[oilyriser]

this might help

if you have the VI and visc at 100C

 

[Patman]

I don't have the VI though, Castrol's spec sheets are very limited.

 

[Gary Allan]

No such luck. Castrol doesn't give the VI on their PDS.

Maybe someone can figure out the trick to getting it to work in simple math. a VI of 100 means there's an increase of 10X between 40C and 100C ..or 1.00 X 10 (VI of 135 = 1.35 X 10). It almost works but there must be some other component because a fluid of 10 CST @ 100C and 50CST @ 40C has a VI of 197 ..not 200

..but it follows that general format ( 1/1.xx X 10 X 100C visc)..at least in those two isolated calculations.

It doesn't work otherwise though

 

[427Z06]

I would guess that the VI is similar to other syn 5w20s. I'd pick a value like 164 for the VI and use the calculator.

 

[Patman]

Quote:

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I would guess that the VI is similar to other syn 5w20s. I'd pick a value like 164 for the VI and use the calculator.

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Based on that, it gives a 40c viscosity of 50.4. That's a little bit higher than other 5w20s, but still a lot less than GC (which is almost 70 cst) and probably about 10cst less than the Syntec 5w30 that's in there now.