PEAK makes peak motor oil, they are known for their antifreeze products before they launched their motor oil line. It's apparently already sponsored the IndyCar when it was first launched in 2007, and is being called "premium motor oil".
Penzoil makes Quacker State Motor oil
mobil makes the oil
Old World Industries: Old World Industries is just the name of the company and they do not refine oil. Their oil is refined by different companies at different times. Who refines their oil as of 4/2013 is anyone guess.
Advance motor oil is made by Coastal
Omni specialty packaging makes the orilly brand oil
Omni specialty packaging makes the orilly brand oil
Advance motor oil is made by Coastal
If it is the conventional oil it REALLY does NOT matter who makes it. Most conventional motor oils are the same. With conventional motor oil just use the recomended viscosity and change it often.
If you go to the Mazda web site it states Castrol motor oil is used.
Edmuns.com has an article on it which says that ExxonMobil is a blender of Honda motor oil.
Motor oil is more dense than gasoline. This is because motor oil is a heavier and thicker liquid compared to gasoline.