Direct injection + Low tension piston rings in modern engine design is causing fuel dilution to go through the roof. Yes, many blackstone UOA reports seem to indicate a relatively safe 1-2% fuel dilution but looking at the low KV100 & Flashpoint numbers, actual readings are probably closer to 5% or more. People who have resampled with Polaris labs (Using GC testing) reveals fuel levels much higher than blackstone.
Yes I know there have been topics posted before about cST shearing vs HTHS viscosity, but normal VII shearing of motor oil without fuel dilution is different than fuel dilution viscosity loss. My reasoning is that HTHS vis should hold up better with normal VII shearing, because the base oil isn't being diluted with fuel which isn't a lubricant (except for diesel).
For example: a virgin 0w20 sample has a KV100 of 8.7 & HTHS vis of 2.7.
If mechanical shearing from normal usage drops the KV100 down by 20% to 7cST, then you'd expect HTHS to drop 10%, down to 2.43cST.
If fuel dilution caused the same KV100 drop to 7cST, wouldn't the HTHS drop more than 10% since the base oil has been diluted? I doubt the VII polymers are able to bind with raw gasoline?
Yes I know there have been topics posted before about cST shearing vs HTHS viscosity, but normal VII shearing of motor oil without fuel dilution is different than fuel dilution viscosity loss. My reasoning is that HTHS vis should hold up better with normal VII shearing, because the base oil isn't being diluted with fuel which isn't a lubricant (except for diesel).
For example: a virgin 0w20 sample has a KV100 of 8.7 & HTHS vis of 2.7.
If mechanical shearing from normal usage drops the KV100 down by 20% to 7cST, then you'd expect HTHS to drop 10%, down to 2.43cST.
If fuel dilution caused the same KV100 drop to 7cST, wouldn't the HTHS drop more than 10% since the base oil has been diluted? I doubt the VII polymers are able to bind with raw gasoline?