Originally Posted By: Jeffs2006EvoIX
One thing I will admit is Amsoil cP for their 5w40 full saps oil which I would call Mobil 1's 0w40 competitor is WAY better. cP of 5400 vs Mobil 1's 31000 that is huge!
Everything else seems to bea wash between the 2.
Would this be a good reason to switch to Amsoil? Maybe if you live in Canada.
But Mobil 1 new brew must have something in it causing those high cP's.
What a difference.
Jeff
You aren't comparing the same thing
You are looking at CCS viscosity, which is measured at -30C for a 5w-XX oil.
Mobil does not provide us with a CCS viscosity for Mobil 1 0w-40. However, because it is a 0w-XX oil, its CCS viscosity must be less than 6,200cP @ -35C.
The number you are looking at for Mobil 1 0w-40 is MRV, which is measured at -40C. Amsoil does not list an MRV value for their Full-SAPS 5w-40, but the pour point is -39C, which is above where MRV is measured. The limit for a 0w-xx MRV is 60,000cP @ -40C BTW.
Using the halving/doubling rule for 5 degrees here, odds are that the Mobil 1 0w-40 is about half the viscosity at -35C than the AMSOIL 5w-40, which means it is again probably half the viscosity at -30C. Even if Mobil 1 0w-40 was right at the CCS limit (doubtful) for a 0w-xx and was 6,200cP @ -35C, it would be around 3,100cP at -30C, significantly lighter than the 5,433cP of the AMSOIL 5w-40.