Ok so we all know that when PQIA tested 5w20 conventional oils, the Pennzoil Conventional and Quaker State Conventional stood out with very low NOACK & a very good low temp -30C viscosity which can only be explained by the use of Group III base stocks.
http://www.pqiamerica.com/Feb2014/consolidated5w20ALL.html
The most popular theory is that Shell had an over supply of GTL base stocks & maybe some lucky batches were made with it instead of a regular Group II base.
I have a different theory. I believe that it wasn't just a few lucky batches, but maybe up to 50% of all Pennzoil Conventional and Quaker State Conventional are made with a Group III+ base.
My reasoning:
-Group III+ base stocks have a VI of at least 140 which is very close to the 155 VI of the oils tested
-Regular Group II base has a VI of 80-119 which means a lot of VI improvers must be added to reach 155 VI
-More pour point depressants must be used with regular Group II to get the low temp performance up to spec
It might be cost effective to just use a Group III+ base stock in Pennzoil Conventional and Quaker State Conventional which doesn't require the use of VI improvers for "dino spec" oils of only ~155 VI. Also, not requiring as much pour point depressants to achieve low temp specs is another cost saver.
On paper it looks like the only differences between Pennzoil Conventional and Pennzoil Platinum is that PP has more VI improvers in it which also increases NOACK from 6.5% to ~10%, and maybe a higher TBN to support longer drain intervals.
http://www.pqiamerica.com/Feb2014/consolidated5w20ALL.html
The most popular theory is that Shell had an over supply of GTL base stocks & maybe some lucky batches were made with it instead of a regular Group II base.
I have a different theory. I believe that it wasn't just a few lucky batches, but maybe up to 50% of all Pennzoil Conventional and Quaker State Conventional are made with a Group III+ base.
My reasoning:
-Group III+ base stocks have a VI of at least 140 which is very close to the 155 VI of the oils tested
-Regular Group II base has a VI of 80-119 which means a lot of VI improvers must be added to reach 155 VI
-More pour point depressants must be used with regular Group II to get the low temp performance up to spec
It might be cost effective to just use a Group III+ base stock in Pennzoil Conventional and Quaker State Conventional which doesn't require the use of VI improvers for "dino spec" oils of only ~155 VI. Also, not requiring as much pour point depressants to achieve low temp specs is another cost saver.
On paper it looks like the only differences between Pennzoil Conventional and Pennzoil Platinum is that PP has more VI improvers in it which also increases NOACK from 6.5% to ~10%, and maybe a higher TBN to support longer drain intervals.