Anyone experienced more MPG by running Exxon Synergy gas?

ExxonMobil is tops in my car.
Regardless if true or not ExxonMobil does advertise more mpg on their website at least they did a few years ago. It's a crap shoot... Since it's closer to ExxonMobil... See if that station is listed on Upside the gas savings app. My local one is...

https://www.upside.com/users/fuel
 
My wife’s CRV get noticeably better MPG with Shell Premium* but my Tacoma only slightly and maybe not attributable.

Have not seen or tried Exxon

*Compared repeatably with Costco Premium. In fact half blind, I know which fuel by 1-2-3 mpg better. We always run premium in this little 1.5L turbo and so far NO fuel dilution. Honda has really fuel mapped this engine for detonation prevention, therefore leans out only when zero knock/pre det detected. I firmly believe people with fuel dilution problems in the 1.5 run ~88 regularly.
 
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If I have a choice and the price is the same I use Exxon regular grade gasoline. Mobil gasoline is supposed to to be very similar if not the same as Exxon. Driving from Florida to NY 2 years ago (in our Ford Escape 2.5) I filled up with Exxon in Virginia and got noticeably better MPG (4 to 5 mpg more....normally get 29-31 @75mph but got 33-36 with Exxon) than any of the other brands I used. The same thing happened this past Spring. I'm pretty certain I filled up at the same Exxon station both times so maybe they had premium in their regular tanks. Also, I saw a video a few years ago that showed Exxon regular had the most detergent of all regular gas tested.

PS: There was a Chevron station in Florida whose regular gas must have been premium because every time I filled up there I could feel the difference. The gas at the Chevron station 5 miles away didn't give the same improved feeling.
 
What gasoline does Costco use?
I've thought that they use whatever gas is the cheapest at the time, which means you could be getting Mobil, Shell, or whichever brand is cheapest for them at the time.
 
pbm said:
If I have a choice and the price is the same I use Exxon regular grade gasoline. Mobil gasoline is supposed to to be very similar if not the same as Exxon. Driving from Florida to NY 2 years ago (in our Ford Escape 2.5) I filled up with Exxon in Virginia and got noticeably better MPG (4 to 5 mpg more....normally get 29-31 @75mph but got 33-36 with Exxon) than any of the other brands I used. The same thing happened this past Spring. I'm pretty certain I filled up at the same Exxon station both times so maybe they had premium in their regular tanks. Also, I saw a video a few years ago that showed Exxon regular had the most detergent of all regular gas tested.

PS: There was a Chevron station in Florida whose regular gas must have been premium because every time I filled up there I could feel the difference. The gas at the Chevron station 5 miles away didn't give the same improved feeling.
Click to expand...
That's about a 20% difference, they must be putting something other than octane molecules in their product.

What it is I do not know that would give that great of an energy density difference.
 
kschachn said:
That's about a 20% difference, they must be putting something other than octane molecules in their product.

What it is I do not know that would give that great of an energy density difference.
Click to expand...
Not speaking for PBM but I know how Honda does it with their 1.5T. Their fuel enrichment with lower octane fuels comes on pretty strong. Hence the better MPG with 92+. It is real.

We can easily demonstrate it, tank after tank, back and forth.
 
kschachn said:
That's about a 20% difference, they must be putting something other than octane molecules in their product.

What it is I do not know that would give that great of an energy density difference.
Click to expand...
I've used Exxon gas many times since and never had that result again but I track my mileage pretty closely while on long trips and that's what happened. The only other possible explanation is that on the next fill-up after the Exxon...the automatic shut off went off early and I inadvertantly underfilled the tank.
As someone who keeps adding gas after the auto s/o (which I know is not good to do because it can hurt the vapor cannister) I'd be surprised if that happened but it's the only other possible explanation.
 
i bought costco gas one time. we would burn half a tank on a specific trip using shell. the time I filled up with costco the car was down to a quarter of a tank. never again.
 
In the 1960s, gasoline marketers set their own standards and specifications for fuel. Some were blended to warm up engines quickly to get them to operating temperature. Others were blended to give better mileage on long term trips.

Those days are pretty much over. The EPA provides specifications that all marketers in a region must meet, so the existence of different formulations affecting mileage is very limited. About the only difference now is additive packages, which I doubt anyone would notice from tankful to tankful.
 
That’s one of the fuels I use - but I’m not going to claim I can accurately measure MPG in any vehicle …
That is likely something EMRE did in testing …
 
Keep in mind that, what ever the % of cost more that one gas brand or octane level is compared to the brand or octane that you normally use, you'll need to get that same % better in fuel economy in order to break even...every single tankful of fuel.
 
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