Conventional oil = semi synthetic?

Regular oil is full of sulfur. When a car is driven short distances and doesn't warm up enough to evaporate the condensate the water combines with the sulfur and makes sulfuric acid.

No, it's not. About the only oil I can recall using sulphur in any significant quantity in its formulation is Royal Purple's old Synerlec product, which is what coined the nickname "Royal Sulphur", as it (Synerlec) was a sulphated ester.

Sulphur that finds its way into the sump is due to the process of combustion and gets there as a result of blow-by. This is why oils are highly based with components like calcium, which neutralize the acids produced so that they don't cause damage. This is measured by way of TBN in used oil analysis. We also measure TAN, which is Total Acid Number. This can be skewed by formula however, which is why looking at remaining TBN is important.
 
Coal and oil from fossil sources are full of sulfur. Synthetic is not. During the 70s the EPA mandated scrubbers on the stacks of coal fired electric generating stations because the sulfur going into the atmosphere created acid rain. The sulfur and rain combined to make sulfuric acid.
 
Coal and oil from fossil sources are full of sulfur. Synthetic is not. During the 70s the EPA mandated scrubbers on the stacks of coal fired electric generating stations because the sulfur going into the atmosphere created acid rain. The sulfur and rain combined to make sulfuric acid.

Diesel fuel historically (particularly in North America) has had some sulphur in it, but there is basically none in modern base stocks. As I noted, the sulphur and subsequent acids that make their way to the sump are the product of combustion, which is why engine oils are based products, as these are used to neutralize the acids. Calcium is one example.

Little read on sulphur in diesel here from Lubrizol and how lubricants are formulated to neutralize acids:


And an article from ALS on sulphur in base stocks:

A quote:
ALS said:
Base oils contribute very little sulfur to engine oils these days. Groups II or III and IV base oils used to formulate engine oils have very low or no sulfur. Most base oils used to formulate lubricants for engine oils use Groups II or III base oils. Higher sulfur Group I base oils are more commonly used in industrial lubricant applications, though there are still some engine oil applications. Group IV is a fully synthesized base stock that is sulfur free and is used in combination with other base oil groups or 100% for extreme operating conditions.

The reduction in sulfur using Groups II or III base oil, which are in wide use, does have the advantage of allowing formulators to control the level and type of sulfur additive compounding in the finished lubricant product. This also reduces the presence of active sulfur in the base oils which can form acids with the presence of moisture and other chemicals. In some Group II base oil a little bit of sulfur is actually added back in as an antioxidant.

Hope that helps.
 
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