Originally Posted by Gokhan
Originally Posted by OilUzer
remember xWy and y minus x
delta ...
Less delta doesn't always necessarily mean less vii.
amount of needed vii (vm) depends on the base oil as well as delta.
I think if the base oil is not very good, it will ultimately result in a higher vii oil. Good base oils will result in a natural higher vi oils with less vii.
That's why 0W20 in ZeeOSix example (vs. the 10W30) has a less vii even though both have a delta of 20. That means 0W20 had a better base oil. Kind of makes sense since typically 0W oils require a better base oil dealing with lower temps ...
So 10W30 htfs is getting punished by it's base oil per Gokhan ... Whereas it's hths is significantly higher.
However, an inferior base oil will require higher vii (amount is delta dependent) . So I am thinking there is some indirect relationship there but Gokhan is saying "htfs only depends on the base oil". Maybe he can elaborate.
Anyway I'm just analysing that data and not saying it's wrong or right.
Edit:
I guess I kind of see what Gokhan means. htfs depends on base oil ... but so does vii.
vii also depends on delta.
Are you saying htfs is independent of delta?
You take a base oil plus a DDI package before you blend in the VII. It will have a certain base-oil KV100 and base-oil viscosity index VI -- before the VII is added. The base-oil viscosity index VI will be higher for higher-quality base oils and higher API group numbers. The HTFS equals to the HTHS
before you add the VII. In other words if you measure the HTHS before you add the VII, it will be equal to the HTFS.
After you add the VII, both the KV100 and viscosity index VI increase. The HTHS also increases and it is no longer equal to the HTFS.
Ok, I see what you mean.
So in case of the 10W30 is ZeeOSix's example, hths was significantly increased after added vii and if I understand you correctly, htfs (much lower than hths) is a better representation of the oil strength.
I now have a couple of big picture type of questions and/or issues:
1-
Based on your info, I am thinking hths would be a useless parameter since its not a true representation of what's going on.
So why is it published and/or talked about so much in the industry?
2-
At the same time, I am thinking why would an intermediate measurement (htfs) prior to added vii be of a more importance than a final (after added vii) measurement?
Basically it sound like throw hths in garbage
No?