"IF I AM READING THE CHART CORRECTLY, there is NOT a drop in viscosity from 100*F to 212*F but actually an increase on the stated oils."
You are not reading the charts correctly, and you are using the word 'viscocity' incorectly.
Viscocity is the property of a fluid that tells one how fast the fluid moves in relation to pressure being applied. Viscocities are measured in absolute (Pascals) and Kinemetric (Poise) scales.
The weight of an oil is a range of viscocity at a particular temperature. For example a 30 Weight oil has a viscocity of 9.6 to 12.4 centiStokes at 100dC.
All oils thicken on the viscocity scales as the temperatures go down. Straight weight oils thicken a lot more than multigrade oils thicken. The Viscocity Index is a measure of how much the oil refuses to thin as it heats up. A straight weight oil generally get a VI around 100%, while a 0w30 weight oil can get a VI of 180-190. This means that the multiweight oil thickens at half (100%/190% = 54%) of the rate of the straight weight oil.
An engine designed to run down the highway with a 30W oil desires an oil with an operating viscocity of 10-20 cSt.
At startup, when the oil is not at operating temperature, the oil is INVARIABLY thicker and this is shown in the viscocity (either measurement means); however the (SAE) weight grade of that oil has not changed! only its actual viscocity!
So, if you have an engine that is designed for a 10-12 cSt oil at full operating temperature--that engine WANTS a 10-12 cSt oil at startup. Since oil technology is not currently capable of producing constant viscocity oils, you should be looking for an oil with a cST viscocity as low as possible with the constraint that this oil at full operating temperatures still fits in the 10-12 cSt range.
Currently there are 0w30 oils that have mid-50 cSt viscocities at 40dC and still have 10 cSt viscocities at 100dC. {A straight 30W oil will ahve a startup viscocity around 120 cSt at 40dC} These multi-weight oils pump through the engine faster under cold startup conditions and still protect the engine at operating temperatures.
So the reason you want the 0w30 oil when the manufacture specifies 10w30 is that YOU want your car to LAST longer then the manufacture wants your car to last!
You are not reading the charts correctly, and you are using the word 'viscocity' incorectly.
Viscocity is the property of a fluid that tells one how fast the fluid moves in relation to pressure being applied. Viscocities are measured in absolute (Pascals) and Kinemetric (Poise) scales.
The weight of an oil is a range of viscocity at a particular temperature. For example a 30 Weight oil has a viscocity of 9.6 to 12.4 centiStokes at 100dC.
All oils thicken on the viscocity scales as the temperatures go down. Straight weight oils thicken a lot more than multigrade oils thicken. The Viscocity Index is a measure of how much the oil refuses to thin as it heats up. A straight weight oil generally get a VI around 100%, while a 0w30 weight oil can get a VI of 180-190. This means that the multiweight oil thickens at half (100%/190% = 54%) of the rate of the straight weight oil.
An engine designed to run down the highway with a 30W oil desires an oil with an operating viscocity of 10-20 cSt.
At startup, when the oil is not at operating temperature, the oil is INVARIABLY thicker and this is shown in the viscocity (either measurement means); however the (SAE) weight grade of that oil has not changed! only its actual viscocity!
So, if you have an engine that is designed for a 10-12 cSt oil at full operating temperature--that engine WANTS a 10-12 cSt oil at startup. Since oil technology is not currently capable of producing constant viscocity oils, you should be looking for an oil with a cST viscocity as low as possible with the constraint that this oil at full operating temperatures still fits in the 10-12 cSt range.
Currently there are 0w30 oils that have mid-50 cSt viscocities at 40dC and still have 10 cSt viscocities at 100dC. {A straight 30W oil will ahve a startup viscocity around 120 cSt at 40dC} These multi-weight oils pump through the engine faster under cold startup conditions and still protect the engine at operating temperatures.
So the reason you want the 0w30 oil when the manufacture specifies 10w30 is that YOU want your car to LAST longer then the manufacture wants your car to last!
