Winner, we had the lab techs at shell do a test on different oils back in my Harley days and the resulys were the same. Some small differences in detergents but that was about it. We did synthetic also and that was even more close. This test all begain because of a arguemnet over screamin eagle oil versus mobil1 or what have you. Lets just say the container is pretty for the Screamin Eagle at at the time was like 10.00 bucks a quart.