Oil Definitions | 5W30 | 10W30
So there is a million synthetic oils out there and performance guys are always asking the question- which one works best for my motor? Which one should I use? Why is that one better than this one? etc… So I have taken the liberty to do what all consumers should do, but don’t actually have the time to do- go out there and research each oil and compare them against one another.
Listed below is the definition and explanation of each point used to compare the oils on the following pages:
Viscosity index
- Viscosity is a measure of how “thick” a fluid is. The importance of viscosity in motor oils revolves around how your motor is put together. Getting too thick of an oil means that the oil will be harder to pump through the parts (especially very tight clearance bearings etc). This becomes an even bigger issue the cooler the temperatures drop as oil becomes increasingly viscous (picture squeezing honey out of a bottle that came out of a fridge, versus putting the bottle in the microwave and doing the same thing). On the flip side, too thin of a motor oil means that the oil will “shear” or break down under stress (such as when racing or at higher RPM) and fail to lubricate your parts properly
- When looking at oils, they will be rated by a Viscosity Index the higher the number is, the longer it will take the oil to become thicker when the temperatures drop, while at the same time, it will also take that same oil longer to thin out (allowing it to possibly shear while the motor is spinning at higher RPM). In other words, the higher this number the better.
Flash Point
- Flash point is exactly what it sounds like, it is the temperature at which the oil gives off vapours that can be ignited when a spark is present thereby causing a fire. The higher the flash point the better
Fire Point
- The fire point is similar to the flash point, except at this temperature the oil will continue to sustain itself and burn for at least another 5 seconds after the spark has been extinguished. The higher the fire point the better
Pour Point
- This is the lowest (coldest) temperature that an oil will still behave as a liquid and remains pourable. Past this temperature the oil will be much harder to pump / flow through the engine. The higher the number the better
Four Ball Wear Test
- This is a test that measures how much wear takes place when using an oil. The lower this number is the better, as less wear is taking place
So let’s take a look at each of the oils (please click which oil you would like a comparison of).
Also note, oil will almost always spark a debate – If you found the above to be useful to you, please share it among your car forums and social groups.
Oil Definitions | 5W30 | 10W30
Actually viscosity index improvers are nothing more than polymers and the more you use, the less actual oil you get in a bottle.
The VI improvers are the first thing to fail under heat and shear so oils with very wide viscosity ranges should be avoided if possible.