[masraum]

Originally Posted by Bob Kontak

Good question. They all have additives but he surely used the same type of gas in the test.

Can the public buy non-additive (fungible) gas?

I'm sure all of the gas in his test came from the same gas can, so all the same.

Top Tier gas has certain amounts and types of additive, and they make a HUGE difference in the amount of deposits left by the gas. I don't know what non-top tier gases have, but apparently, it's likely to be inadequate.

Even just the first 1:20 of this video is interesting. The whole video is ~7min.
"Top Tier" is a certification that has standardized tests that require maximum amounts of deposits left per intake valve.

According to the video, non-top tier gas in the test left 660mg of deposit per valve during the standardized test, and the top tier gas only left 34mg of deposit per valve.
And apparently this year there's a "top tier plus" coming out that is essentially the result of the new Direct Injection motors.