The OIL thread.

[Sinfix_15]

I understand the "crucial point" very well. I certainly understand that not all oils are equal. Hence why i also specified the brands that i generally run personally rather than the cheapest oil you can buy.

yeah, but you said there's "no lubrication benefit to synthetic" which isnt exactly true either. Synthetic degrades slower than crude and maintains it's viscosity longer. Even if Xbrand crude tests about the same as Xbrand synthetic, the crude is going to sheer down quicker than the synthetic. Most typical shelf brands drop a weight half way thru the interval.... vs the synthetics which allow you to drop a weight below your recommendation since it's more sheer stable. Temperature is a bigger factor than being a "high rpm race engine" a jeep going on a camping trip in arizona would put much more stress on a oil than a corvette on road atlanta.

Thats some good stuff. Found these to sort of validate what i've read in this thread -

Castrol Syntec is not a Synthetic Oil - F150online Forums

Which are true(!) PAO (Class IV) Motor Oil brands? - Bob Is The Oil Guy

For me i'd rather use a "Class 4" oil. So i guess back to Mobil 1 it is for me. I like knowing my money is going towards a true synthetic for my motor.

So Amsoil - Does this oil test better than Mobil 1? And provide longer change intervals?

I see the website and read information about it and just seemed so infomercial like. Maybe that's where Mobil 1 wins in the marketing strategy.

Amsoil tests better than Mobil and lasts longer. Mobil is good oil though and like you said, is a true synthetic.