Effects of fuel brands on mileage

[a64pilot]

I've bumped into discussions of this as well. There is something to it, not all automotive fuels are created equal. There is something called "top tier fuel" read here Top Tier Gasoline Toyota is one of the sponsors.
If I'm posting previous knowledge, I apologize. I am trying to search to ensure I don't, but I'm not known for my computer prowess.

[abq sfr]

Originally Posted by a64pilot

I've bumped into discussions of this as well. There is something to it, not all automotive fuels are created equal. There is something called "top tier fuel" read here Top Tier Gasoline Toyota is one of the sponsors.
If I'm posting previous knowledge, I apologize. I am trying to search to ensure I don't, but I'm not known for my computer prowess.

Yes, lots of previous discussion on this. One of the main points is that in certain parts of the country all gas comes through the same pipeline, and different brands take that same gas and put their own identifying markers (aka additives) into it. To complicate things, discount stores like Costco purchase whatever brand is excess, can even be Shell or Chevron or ??? A local distributor here in NM told me these markers have no performance value, they are just a legal identifier. The Top Tier designation has been argued over, I think the general consensus is that it really does not mean that much, but there are others here that will argue that point. Your Mileage May Vary.

[dwreed3rd]

F.Y.I. Your comment, "Your Mileage May Vary". It's "Top Tier Detergent Gasoline" and was developed to increase the level of detergent additive in gasoline. The EPA requires that all gasoline sold in the U.S. contain a detergent additive. BMW, General Motors, Honda and Toyota felt the EPA requirements were insufficient to keep engines clean. TOP TIER was developed to give fuel marketers the opportunity to differentiate their higher detergent products. Controversial yes, but not anything that affects mpg.
Excellent post. Just wanted to clarify that "Top Tier" isn't about mileage it's about detergent.

[a64pilot]

Your absolutely correct, the "top tier" is not about mileage, it's about detergent, but any internal combustion engine will run more efficiently when clean as opposed to not being clean. One of the reasons to run (Chevron) premium fuel as opposed to their regular is that there is more Techron (a detergent additive) per gallon of premium than there is for regular. Now I'm NOT abdicating running premium fuel in a Prius, but in your "other" car a tank or two of premium fuel has been known to clear up some drive-ability issues.
One possible reason two identical automobiles operated identically may have different FE is one may be habitually using "better" fuel than the other. I don't think there will be much if any difference in one tank of "top tier" fuel, but I do believe that habitually using "top tier" fuel is beneficial for FE.
There are many variables that go completely unnoticed by the general public, but when you really start tracking FE, there will be differences from one tank of fuel to the next that are difficult to explain except for differences in the fuel itself, and there are differences.