If you REALLY want to deep dive into the "my oil is better than your oil, and I'll be all butthurt if you disagree with me" territory go check out www.bobistheoilguy.com

You will find a ton of information on oils there.

I don't use Amsoil, but it most certainly isn't snake oil. It is a legitimate group IV synthetic (just as Mobile 1 and many others are). I use Redline myself, which is a group V synthetic.
It may be the pricing on the products or how their sold that upsets some, but they are in no way snake oils.

It's not easy to determine if one product works "better" than another- whatever "better" means. To truly determine something like that would require a large amount of very expensive tests.

It is possibly true that some oils prevent internal wear better than others, or that some filters filter "Better" again whatever that means, it's all academic.

I'm more interested in someone pointing out a non brand name low quality oil. Because we're all supposed to use a brand name high quality product.

 

Petroleum based synthetic! Only a crap ton of lawyers made that oxymoron possible.................................

 

Another explanation I've run across is that "true" synthetics contain "0" wax and therefore have a natural characteristic of not thickening as much or as quickly as dino oils do as they cool. This means there is less of a need for the, long chain polymer, viscosity modifiers in the additives package which makes an oil "multi-grade". It is these polymers which shear, not the base oil (so much), and this is mainly what accounts for a synthetic's durability. This innate temperature characteristic of true synthetics, in other words, means the Blender can use a relatively higher viscosity synthetic base oil and less of the shear prone viscosity modifiers when blending a multi-grade product. Comparatively, Blenders using a dino base must use a lower viscosity base oil and add a sufficient, (larger), amount of the modifiers to thicken it to spec. for when running hot.

Viscosity is temperature dependent and oils are spec'd between 100 deg. C and 40 deg. C. It is when ambient temperatures fall below the 40 deg. C range that synthetics provide a huge benefit. As ambient temps continue to drop, the (thickening) viscosity differences between synthetic and dino oils continues to widen. On cold start mornings your synthetic supplied engine becomes properly lubricated measurably sooner than it would if it had a dino oil in it. Over the years and hundreds or thousands of cold starts, this has got to make a difference IMHO. I'm in Canada so ,,,,,, !!

 

Testify. I once had the misfortune to own a 1980 Pontiac Sunbird- the evil spawn of the even more horrible Chevy Vega. At the time I had to park outside and had no way to plug in an engine heater. Once the temperature fell to much below 20F, the damn thing woudln't crank over fast enough to start. Totally out of desperation, I decided to put Mobile 1 in the engine- it having just hit the market and was bragging about it's cold start properties.

Once I had that oil in the engine, it cranked right over and easily started. Even at -30F it would start, when most of the other cars in the parking lot wouldn't. The crappy engine on that car consumed a quart every few weeks, so I had to keep adding more at then $5 per quart- but so totally worth it to be able to start the damned car.