Originally Posted By: chubbs1
Originally Posted By: CATERHAM
One theory I have on the dramatically different SN Castrol EDGE 0W-20 (VI drop from 220 to 161) and to a lesser extent their 5W-20 formulations over the prior SM versions and the need to reformulate is related to the GF-5 requirement increase in deposit control.
I posit that the ultra high VI SM contained a ton of VII's that undoubtedly sheared a lot before stablizing and those shear byproducts increased engine oil deposits which made it harder to meet the GF-5 clean requirements; hence the reduced VI in the SN oil.
Didn't we get into an "argument" about the use of too many VII's in oils? It seems as if you have changed your position.
I totally agree w/ this post CATERHAM. You know your stuff and I am not challenging you but I just can't stand oils w/ too high of a VI, especially a semi-syn like Toyota 0w20....it makes me wonder if they are just shoveling blocks of VII in their oil. There is NO way it is even close to natural. I don't see why people get bent out of shape by a VI of 160-175. Very good balance for a QUALITY base oil.
No argument that a naturally high VI is preferable to one that is derived in part from the use of VII's but that can't be done without using GP IV and GP V base oils exclusively and even then you won't get a VI higher than the mid 170's not to mention being very expensive. Just compare the price of a Motul 300V 0W-20 or Fuchs Titan GT-1 0W-20 to Mobil 1 or Toyota and they're 3 to 4 times the price.
Since most 0W-20's like Toyota, Castrol EDGE, PP etc are GP III based they all use VII's. But there are many different types and qualities of VII's. What's important is of course the resultant VI of an oil in service and in the case of the Toyota 0W-20 that's still a VI of around 195 which is mighty good.
If there wasn't a net benefit in using them you wouldn't find them in OEM spec' oils and the advantage is very real.
Comparing Mobil 1 0W-20 (VI 173) and Toyota 0W-20 (VI 214) translates into the Toyota product that is 25% lighter at room temperature and a whopping 35% lighter at 0C. That's why I personally like these ultra high VI oils; the fact that they also contain a boat load of organic moly is a bonus.
Originally Posted By: CATERHAM
One theory I have on the dramatically different SN Castrol EDGE 0W-20 (VI drop from 220 to 161) and to a lesser extent their 5W-20 formulations over the prior SM versions and the need to reformulate is related to the GF-5 requirement increase in deposit control.
I posit that the ultra high VI SM contained a ton of VII's that undoubtedly sheared a lot before stablizing and those shear byproducts increased engine oil deposits which made it harder to meet the GF-5 clean requirements; hence the reduced VI in the SN oil.
Didn't we get into an "argument" about the use of too many VII's in oils? It seems as if you have changed your position.
I totally agree w/ this post CATERHAM. You know your stuff and I am not challenging you but I just can't stand oils w/ too high of a VI, especially a semi-syn like Toyota 0w20....it makes me wonder if they are just shoveling blocks of VII in their oil. There is NO way it is even close to natural. I don't see why people get bent out of shape by a VI of 160-175. Very good balance for a QUALITY base oil.
No argument that a naturally high VI is preferable to one that is derived in part from the use of VII's but that can't be done without using GP IV and GP V base oils exclusively and even then you won't get a VI higher than the mid 170's not to mention being very expensive. Just compare the price of a Motul 300V 0W-20 or Fuchs Titan GT-1 0W-20 to Mobil 1 or Toyota and they're 3 to 4 times the price.
Since most 0W-20's like Toyota, Castrol EDGE, PP etc are GP III based they all use VII's. But there are many different types and qualities of VII's. What's important is of course the resultant VI of an oil in service and in the case of the Toyota 0W-20 that's still a VI of around 195 which is mighty good.
If there wasn't a net benefit in using them you wouldn't find them in OEM spec' oils and the advantage is very real.
Comparing Mobil 1 0W-20 (VI 173) and Toyota 0W-20 (VI 214) translates into the Toyota product that is 25% lighter at room temperature and a whopping 35% lighter at 0C. That's why I personally like these ultra high VI oils; the fact that they also contain a boat load of organic moly is a bonus.
