This base oil needs to have certain chemicals called additives added to it to enhance its performance as a good lubricating agent. These additives together perform diverse functions but each additive has a specific use and together they give the lubricant its character. Depending on the engine the lubricants is to be used; the ratio of base oil to additives varies from 85:15 to 90:10.
Base oils: Base oil is highly refined crude oil or in some cases a synthetic composition and they account for roughly one percent of the total output of petroleum products from crude. It is essentially a by -product obtained during refining of crude and is obtained along with the heavier ends.
Different operating conditions like moisture, dust, exposure to air, high/low temperature, high pressure, corrosion, etc dictate which base oil and which additives should be used.
