All of the below is based on either Industry fact and or knowledge and we believe that better education when it comes to Lubricants will result in an opportunity for you to make better choices.
We have simplified to some extent so as to make it all more easily understood.
Step 1 ... Base oils
Like building most things, it all starts with the foundations and when it comes to lubricants that is the base oils and this is where the chemistry starts.
Choosing the base stock type is a determining factor in the finished product quality, low quality starts with "recycled" group 1 base oils, next up is solvent refined virgin group 1 and then we get into the better hydrocracked group 2 and group 3 and so on, group 4 base stocks (PAO's) are rarely used in most of todays oils and are usually reserved for extreme situations (more on base oils here) as they are very expensive when compared to all others.
Base stocks are available in various viscosities (thickness) and by blending 2 or more different base stocks to a given formulation results in the correct "base viscosity" for a given product.
Companies wanting to compete on price usually elect to go for the cheaper recycled and group 1 base stocks, group 2 and group 3 base stocks are more expensive to produce making it difficult for those electing to use the better base stocks to compete, having said that however, dearer price is not always an indication of better quality, it just may be that the marketing is better and more expensive.
Another factor to be considered is the oil companies own use of the word synthetic, world wide it is the accepted norm that when it comes to using the term semi synthetic that the synthetic base stock content of that product is at least 50% of the total base stock but many opt to go with 30% or even less because of cost factors. In Austalia there is no legislation in this to adhere to so most do what ever they want and get away with it.
Be aware of the terms "synthetic enhanced" or "synthetic fortified" as this means nothing other than indicating an oil company wanting to use the word "synthetic" on their label in an attempt to create an illusion of a better product, here there are no set parameters and all they would have to do is have say 3% synthetic for example, to be able to ethically use the term synthetic enhanced etc on their labelling.
The use of recycled base stocks is quite common amongst those companies focussed on profit first and this is to your detriment, do not be fooled into thinking that a company use's recycled base oils in only some products and not others as many claim, the rule of thumb is that if they are prepared to "cheat" on some then they will most likely cheat on many.
Ask your supplier as to what base stocks they use in their products, it is your money you are spending and you are entitled to know and there are ways of checking, for example in hydraulic fluids where the additives are clear (no colour) the finished recycled product will be darker than the virgin product and the group 2 & 3 products will be clear, ask enough and you may well be surprised as to who is using the poorer quality base stocks.
In summary, base stock choices are the first and a critical point in determining product quality and performance.
Step 2 ... Additives
This is where the chemistry gets deeper but it is not as involved as you may think.
There are only a handfull of additive manufacturers world wide that are considered to be leaders in the industry and it is those leaders that work closely with Original Equipment Manufacturers (OEM's) and rating bodies such as API, ACEA, ILSAC to name a few to produce additives to the satisfaction to those OEM's and bodies and we as blenders take direction from those companies when it comes to blending to a specific rating or standard.
We use several but in the main most of our additives come from the Lubrizol Corporation who provide formulation assistance and technical backup in many ways as the additive type and percentage determines the performance rating of an oil as well as other characteristics.
An engine oil for example does perform many duties apart from lubrication such as;
* Cooling of internal components
* Resisting the effects of combustion by products such as soot, acid, sludge etc.
* Cleaning of internal components
* Holding contamination particles in suspension for filtration
and all of the above are very important when it comes to component life
A typical engine oil is made up of additives to the above but also has others to resist the effects on viscosity from heat, this additive is called a Viscosity Index Improver (VII) or some use the term Viscosity Modifier (VM), another called a "Pour Point Pepresent" (PPD) to ensure the oil does not freeze in colder conditions and then come the performance additives that determine an oils performance rating acording to API, ACEA etc.
Viscosity Index Improvers come with different Shear Satbility Index's (SSI) that reflect that products quality and the lower the SSI the better the ability to resist "shear", when an oil shears, the film of oil protecting your component breaks allowing the possibility of metal to metal contact and we all know what can happen there.
VII products vary according to SSI ratings, the poorer (higher SSI) being substantially cheaper than the better with a lower SSI and this is another area a blender can elect to save cost at the expense of quality and many do.
When it comes to the PPD's some blenders reduce the ammount used and some even leave it out altogether to save costs again as they claim PPD's are not really required in hotter climates.
Performance Additives are another area that is critical, the correct type and percentages must be used to be able to claim the relative performance rating and just as important is the choice of manufacturer of those additives.
Step 3 ... Blending methods
There are basically 2 types of blending methods, cold blending and hot blending, some oil companies also use the term "line blending" but this is just another term of cold blending.
Here it is not hard to figure out which is the superior, hot blending is recognised world wide as the best when it comes to bonding all of the components correctly, cold blended products often have far less shelf life suffering from additive drop out.
Another critical factor in blending is blending by weight vs blending by volume, the specific gravity (SG) of an oil changes relatively little when compared to changes in volume over different temperature ranges for example winter over summer.
Hot blending has costs associated in the form of producing heat whereas cold blending has not so the blenders choosing to cold blend have a cost advantage in the market place but usually produce a lessor quality product.
Blending by weight is by far the better choice when wanting to produce a better product.
In conclusion ...
Oil companies can choose to a large extent as to what type of base stocks to use, what type of additives and who they buy from, the quality and then the percentages used, they can also choose what type of methods to use in the blending process.
Those out there on price advantage have chosen to save on costs in an effort to maximise market share and profits and almost without exception are a lessor quality product, some substantially less and this is to your detriment when it comes to the life of your equipment.