My sample size of one shows Exxon 5.1 zero to 60, Shell 4.9.
Sometimes I get wheel slippage, though, so maybe Continentals and Shell are the answer.😀

 

Right on!

 

In most (if not all) markets the Top Tier fuel is the same basic product with the detergent additives used being the only difference. If I recall my recent conversation with a Chevron guy, this transition gradually took place because of the cost of transportation and the fact that gasoline products are now a generic commodity. Even if you are near a Chevron (or XXX) refinery or not too distant pipeline location (with storage tanks) you are probably not running Chevron (or XXX) fuel. Supply and logistics result in trading among brands. In my area Chevron recently sold their storage tank ownership to another competitor that will deliver fuel to the Chevron branded stations. Their fuel, even before the sale, was coming from several other refiners besides Chevron.
The Top Tier designation is for fuel with additives that meet a higher standard than the basic Federal minimum.
Apparently gasoline has been traded for a long time...just not well known by consumers.

 

Good data on fuel additive packages here:

 

He's become a reliable source for oil and stuff. (Far superior to bob is the oil guy)

 

Coming from the original post that I made , I drove with Shell fuel for about same distance and it appears that it was just a placebo effect. Both Costco and Shell appears to be similar. In fact , Costco gave 1mpg extra (if that matters)











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The refinery matters. For example my local costco and shell fuel quality is very different, that said, I am in Canada.

 

Costco in Georgia is 93 Octane, and 40--60 cents per gallon cheaper than QuikTrip (top tier). Filled up today for $3.36/ gallon