Where exactly did you find this report that said that penzoil was better than valvoline. Realistically speaking almost all oils are the same that are made by the bigger name companies. I personally dont use penzoil because they used to use high pariffin content oil, but now I just dont use it cause I dont like the ugly yellow that they make the bottles. Seriously though, dont argue brand. Oil comes in four grades from worst to best; Walmart, regular oil, blend, and synthetic. However I really do welcome anyone to prove me wrong. I would always want to put in my car whatever gives me the most bang for my proverbial buck. So if you can tell me where you are finding those tests showing penzoil is better, I will go buy myself a black marker so I dont have to stare at those ugly yellow bottles. BTW Penzoils web-site doesnt count. Remember tests like that can still be biased, to specific attributes of each oil.