Nice arrogant reply you have there prick.
I am keeping things nontechnical so everyone can understand. I wasn't talking about the mass or weight either, but when did I ever mention that? That's right....never.
Also, where do you discredit what I said? I know I am right and so do you.
75w90 and 75w140 will give you the same gas mileage?
That is ridiculous. 140weight will be thicker and restrict movement more than a 90 weight. Restriction requires more power to move hence why you will have more drivetrain horsepower loss with a vehicle with 140 than a vehicel with 90 weight.
How does a increase in drivetrain horsepower loss result in the same fuel economy? That's right....never.
So to boil this down:
XXwYY
XXw= The "W" stands for WINTER and not WEIGHT.
5w is thinner at lower temperature than 10w or 15w. In extremely cold temperatures like where I live , you use 0w30 which is thinner when cold than 5w30.
YY = The weight or thickness of the oil at 100c or when the oil warm up to proper temperature.
Hope this helps everyone dispell the XXwYY myth and what they mean.
A quote from Amsoil's Website:
The answer is that ANY one can be used regardless if your vehicle owners manual says to use, for example, a 5W-30. "W" means winter. In winter weather the 0W oil will flow like a 0W oil, and the 5W will flow like a 5W oil and a 10W will flow like a 10W oil just until the engine warms up. In order to understand the differences one has to first understand that the numerical values given to these various weight oils are strictly empirical numbers. For example, 0W does not mean that the oil has no weight. That is one of the reasons why we say it is strictly an empirical number.
In order to determine the differences between the three oils one has to look at the kinematic viscosity of each lubricant. The kinematic viscosity is essentially the amount of time, in centistokes, that it takes for a specified volume of the lubricant to flow through a fixed diameter orifice at a given temperature.
Let's compare the kinematic viscosity of the three AMSOIL lubricants:
AMSOIL 0W-30 is 57.3 cST @ 40 deg. C, & 11.3 cST @ 100 deg. C
AMSOIL 5W-30 is 59.5 cST @ 40 deg. C, & 11.7 cST @ 100 deg. C
AMSOIL 10W-30 is 66.1 cST @ 40 deg. C, & 11.7 cST @ 100 deg. C.
As you can see from the data above the kinematic viscosities are extremely close. Therefore, whether you use the 0W-30, 5W-30 or the 10W-30 is strictly a matter of choice. With the small differences in kinematic viscosity you would be hard-pressed to detect these differences on initial engine start-up without specialized engine test equipment.
http://www.synthetic-oil-tech.com/d....weight_oil.htm