It's purely BS!! You can actually free up HP not increase it by having a LESS viscosity oil. Also during the time it took to drain the oil and change filter and put everything back including 10 Fn quarts of COLD oil you will show a little HP increase on a dyno. Doesn't mean the oil itself did it. Too many variable to make any kind of conclusion.
As others have stated only a UOA ( used oil analysis) is going to determine which oil protects better. You will see the exact metal content in the oil, from copper ( ughh!) , manganese, aluminum, steel, etc. and those results tell you after many comparisons as to which oil protects better. You WILL NOT gain HP from oil!! You MAY free up 1 or 2 ponies by using a synthetic over a "dino" due to the less friction of the synthetic. As of the latest I've heard in the LSX world of which I also belong, and I hate to say the word, but Pennzoil took #1 in oil comparisons with RP, Mobil1, Castrol, Lucas, Valvoline, and many other top performing ( based on claims) oil. Pennzoil Platinum took the cake and ate it. Now after many years under the hood of various cars I could tell one oil from all the rest due to the gunk and matter that collected in the intake valley and top of heads as well as in the oil pan and I could always tell the customer " you are using Pennzoil aren't you?" They would be like , yeah how could you tell? Then I show them the contents and pictures of where these contents came from and they would NEVER use it again. Pennzoil got a bad rap from the get go because of the amount of ASh used in their oil. That's pretty much what was left behind after being in a motor with 3-4000 miles cahnge intervals and over a 100k teardown. I hated the stuff and after reading the latest UOAs I've seen as hard as it was to put it across the scanner at the store I tried it. I am on my 2nd oil change and haven't drained it to see how it looks but I'm hoping not like water as Mobil 1 has done lately.( 4-5 years).
Supposedly Mobil 1 had changed their proprietary blend and it hasn't been as good since. Now I've heard this for at lest 4 years and still continued on with M1, even in my 10. ( Still on Mobil 1) and out of warranty. Wasn't till a few months ago I decided to change the oil in my WS6 to Pennzoil Platinum. All I can say is the MOST important thing to do to any engine is change your oil at recommended intervals or less. That is the key to long engine life. Like others have said, it's not neccessarily the oils fault as far as breakdown. They are made to breakdown and we have to be responsible as to change it during it's breakdown or prior.:burnout:
