Can we interpolate to get vis@70C?

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Aug 13, 2002
Vis@40C = 80 cSt Vis@100C = 14.5 cSt My normal operating oil temperature is 70C Vis@70C = 47.25 cSt (by linear interpolation) ?? Is that a correct assumption?
You can use linear interpolation on a linear log graph (temperature linear X axis, viscosity Log Y axis). Someone is bound to show it later in the thread.
Originally posted by Patman: Why is your normal oil temp so low? That's not even hot enough to properly burn off moisture.
I agree with Patman...only 158F?
Originally posted by Ferrari: According to my Honda Prelude's shop manual, my engine's normal temperature is 85*C. What do most engines run at?
I believe most engines typically run closer to 100C (212F) Your oil temp should typically run the same or higher than your coolant temperature.
I studied some rheology in uni a few months ago, and its very obvious in the lab that oils do not display linear behavior when it comes to viscocity vs temperature. More like exponential or sigmoidal in some cases. So no, a direct interpolation will not yeild accurate results at all...
Going by the graphs Mobil tech sent to me - with those 2 points, 70 deg C ends up at 30 centistokes BTW, those 2 spec points are the same as Mobil-1 0-40
According to my vis calc program this oil is 29.9 cst @ 70C.
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