Uh oh, another oil discussion

[tajensen]

I was talking to a friend of mine who is attending Wyoming Technical School. He said that his instructors told him that the additives in regular oil are the same as the additives in synthetic oil, and because of this, both oils will lose functionality after the same time interval given the same abuse. With the reputation that WyoTech has, I am hesitant to discredit what his instructors had to say. Any thoughts?



-Tim



BTW, I run Amsoil.

 

[fest3er]

Originally posted by tajensen
I was talking to a friend of mine who is attending Wyoming Technical School. He said that his instructors told him that the additives in regular oil are the same as the additives in synthetic oil, and because of this, both oils will lose functionality after the same time interval given the same abuse. With the reputation that WyoTech has, I am hesitant to discredit what his instructors had to say. Any thoughts?

-Tim

BTW, I run Amsoil.

Yes, the additive packages do get used up over time, even in Amsoil. For example, the TBN of Amsoil may start out at 13 or 14, but as acids are neutralized over time, the TBN will decrease.

That's why, when running bypass filtration and extended drains, you replace the filter(s) on a regular basis and put in make-up oil - it replenishes the additives.

Fest3er

 

[Gary - K7GLD]

And of course, there are other significant advantages provided by synthetics other than their additive packages...

 

[DocStressor]

Your friend is correct. Most oils contain similar additive components which come as “pre-mixes” from Lubrizol and a few other suppliers. The higher end oils try to optimize the mix and some use different detergent/dispersant components and friction modifiers. The difference in performance between Dino and synthetic is due to the properties of the base oil, particularly oxidation and shear resistance. Detergents are “used up” faster with conventional base stocks, particularly Group I oils. As the base oil components oxidize to acids, esters, etc, they are held in solution by the detergents. Thus, the ability of the detergent package to hold junk in solution is compromise as the base oil goes down hill. Synthetic base oils are much more resistant to oxidation so the detergents last longer. Synthetics have a higher viscosity index (VI) than conventional oils. That means that their viscosity decreases with temperature less than conventional oils. In order to make a multi-vis oil such as 5W-30 or 15W-40, viscosity improvers have to be added to the oil. These are molecules that increase in size as they are heated, so the viscosity doesn’t decrease as much with temperature. These compounds tend to become sheared or broken and loose effectiveness the longer an oil is run in an engine. Synthetic oils contain the same viscosity improvers used in conventional oils, but much less is needed to produce an oil with any specific viscosity range. So they tend to maintain viscosity longer than conventional oils.

 

[Cooker]

Once again, Lee's post has some great technical data. Thanks.

 

[tajensen]

Nice one Lee. Thanks to all.