Do some conventional motor oils outperform some synthetic oils?

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Mar 5, 2003
Are there some conventional motor oils that can actually outperform some synthetic oils? The reason I bring this up is because I once tried a supposedly synthetic oil from a major motor oil manufacturer which ran badly in my car. Some of the so-called synthetic oils could even be questionable that they are even synthetic. I have had conventional motor oils run great in my car.

I can also think of a part synthetic oil that I have tried that feels like Mobil 1-I realize that is unscientific but that is what it feels like and sounds like.
Define "synthetic".
Doesn't ExxonMobil use the terms nothing "outperforms" Mobil One in advertising? As long as they do not use any numbers, the courts let them get away with it.

There are a few situations where synthetic (particularly when defined as PAO) may not perform as well as dino.

1. Engines running on leaded Avgas.

2. Engines that already leak or smoke.

3. Engines with excessive blowby.

4. Two-stroke diesels.
I do believe that oil marketers may not mention the numerical margin by which a test standard was achieved, only that it was surpassed.

So you will not find numbers in advertising.
Looking over the uoa's I am not sure that the wear numbers are any better in general. Some petros have good results some syns have good results , if you look at the additive levels of the premium syn oils and compare them to the fleet oils they are close and compare the uoa's they're the same.
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