This was an interesting read. I was glad to see it confirmed with empirical evidence that Top Tier gas is truly better. I have always assumed that was true and buy my gas accordingly. I knew mid-grade was "created" at the pump by blending but it was neat to read about the savings you can get by "blending" the gas your own by pumping equal amounts of regular then premium. Sounds like a lot of trouble to me by then I don't ever use mid-grade gasoline.

 

Interesting indeed. We can only assume that the Top Tier gasoline retailers are Exxon, Shell, and maybe Texaco? BTW, this should be required reading for every Mercedes, BMW, Audi, Range Rover, etc... owner that gases up at Walmart. I've seen it.
I do have some anecdotal evidence about "better" gasoline. When we had our X3 M Sport my wife used to go to Exxon. The engine started knocking over time. We took it to the dealership and they simply told her to start using Shell. Wouldn't you know it? After about 2 weeks of using Shell gasoline the engine was fine without any need for any mechanical repair.

edit: I wonder what the long term effects of ethanol (10% - 15%) will be. We know that it will deteriorate fuel lines over time. I wonder if that gunk gets into the engine.

 

FWIW: If you look up TOP TIER FUELS, there are several more suppliers, than the three, you've listed. 76 (USA)
Aloha (USA)
Amoco (USA, Canada)
ARCO (USA, Canada, Mexico)
Beacon (USA, Canada)
BP (USA, Canada)Breakaway (USA, Canada)Break Time (USA)
Cenex (USA)
Chevron (USA, Canada, El Salvador, Guatemala, Honduras, Panama)
CITGO (USA, Canada)
Conoco (USA)
Co-op (Canada)
Co-op Diesel (Canada - select locations only)
Costco Wholesale (USA, Canada, Mexico)
Costco Wholesale - Diesel (USA, Canada - select locations only)
CountryMark (USA)
CountryMark PLUS (USA)
Diamond Shamrock (USA, Canada)Energy (Mexico)Esso (Canada)
Express Mart (USA - Wisconsin)
Exxon (USA)
Fast Fuel (USA)
Fast Stop - Diesel (USA - select locations only)
Fast Stop Express - Diesel (USA - select locations only)
G500 (Mexico)Hele (USA)HFN - Hawaii Fueling Network (USA)
Holiday (USA, Canada)
Irving Oil (USA, Canada)
Kirkland Signature Gasoline (USA, Canada, Mexico)
Kirkland Signature - Diesel (USA, Canada - select locations only)
Kwik Star (USA, Canada)
Kwik Trip (USA, Canada)
Kwik Trip Express (USA, Canada)
Mahalo (USA)
Marathon (USA)
Metro Petro (USA)
MFA (USA)
Mobil (USA, Canada)

 

Wow. A handful of those names are surprising.

 

I noticed names like QT, Quik Trip, Shell, Texaco and Valero were missing from this list. Those are still top tier

https://www.toptiergas.com/licensedbrands/

 

 

Right on, projektvertx, copy failed to print the second page, O through Z. Thank you for catching that.

 

I fill up almost exclusively at Costco 95% of the time for this very reason. Otherwise I go for BP, Shell, Kwik Trip, etc for the top tier gas. It's worth it to go out of your way for it. My parents used to use Sam's Club gas until it started to cause issues, switched to Kwik Trip and all was back to normal.

 

It does. I remember a friend bought a flex fuel Tahoe years ago. He had to take a trip to Louisiana and thought he'd try E85. He told me that it ran out so fast that he never tried using it again. Here is a pretty interesting list of the effects of ethanol on engines.

List: E10 Engine Damage & Performance Issues.