gas quality and mpg

[nickinva]

I used to only buy gas from a branded dealer, then I heard it didn't matter since they all get gas from the same place and differ only in the (very small amount) of additives. This seemed to be true for my '07 Subaru Legacy and an '01 Honda Civic - it really didn't make any difference for mileage or performance if I filled up at Shell or Sheetz. However, I recently purchased a 2011 Hyundai Elantra and my mileage/performance has been as follows:

7-11: Filled up twice - 32 mpg, very sluggish performance
BP: 1 fill up - 35 mpg, performed quite well
Shell: 1 fill up - 37 mpg, best performance yet

The car is rated at 40 mpg and I drive it about 400 miles per week on the highway.

Now I know that i need to try these brands a few more times and drive under identical conditions in order to conclude that brand matters for this car, but from what I can tell so far, it does.

 

[steve20]

some of my cars are particular about the gas they are fed:

04 Tahoe-will drink anything and perform the same
05 Accord-will sip anything and perform the same
95 Corvette-likes either Exxon or BP
02 Corvette Z06-loves nothing but BP ultimate-anything else, and it's noticeable performance drop.

 

[daves87rs]

I just 89...

 

[SEMI_287]

The Jeep likes BJ's 87 or Sunoco 89. I really like Shell gas but it's nonexistent here.
The Z likes Mobil 93.

 

[meangreen01]

Originally Posted By: nickinva
I recently purchased a 2011 Hyundai Elantra



It's basically a new car, still being broken in and I'm sure you're still getting used to it. What brand gas you put in it doesn't matter. Now if you're talking gas with ethanol or without, that would make a difference.

 

[wallyuwl]

I can tell a difference in performance with grade of gas. I get a mileage increase of about 2 mpg with 93 octane Kroger and Shell. I still get the better performance, but not the better mpg, with other 93 octane gas (Thorntons and Speedway). When in WI I fill up with 89 octane Kwik Trip gas (Top Tier) and it performs well, but I don't get the extra mpg. This vehicle (2010 Equinox with the 2.4L DI) says it can take 87, but it can't. There is a TSB to reprogram the spark timing, but you lose 1 mpg and performance.

 

[Hemi426]

I like Shell gasoline but I have no station within 40 miles. I usually run Exxon but lately I have run a few tanks of Sheetz 87 and my truck is running good. The Sheetz stores in this area sell so much darn gasoline in a day that they get a fueling truck every day or every other day. That pretty much ensures you fresh gas when you fill up. Good food and good coffee also.

 

[qdeezie]

I don't know if it is true, but I was told that the gas trucks have different compartments, so that's why it is possible for them to stop at multiple brand gas stations within the same vicinity.

That's what I've heard, whether or not it is true, I don't know.

 

[sentra]

I don't how one can attribute the 2-3 mpg difference, spread over a full tank of gas, on a change in gas brand. There are just too many other variables that should be taken into account.

 

[Russell]

I generally use Shell 93 since Chevron left KY. I used Sonoco 93 the other day. My car ran very well. However it is the only Sunoco station I have seen in central KY.

 

[rshaw125]

Depends on where you live. Up the East coast it all comes from 1 of 2 pipelines. Here where I live in NC it all comes from the facility near I-95. I used to buy Shell but switched to Costco and the only difference is the price.

 

[rg200amp]

Originally Posted By: rshaw125
I used to buy Shell but switched to Costco and the only difference is the price.


False.

The base fuel may be the same. However Shell uses a different (better and more robust) additive package than Costco.

 

[Jimmy9190]

I think is odd that the OP has less power on the 7-11 gas in his area. I use 7-11 and my truck runs great on it and I get good MPG too. Maybe the 7-11 gas up where OP lives has more ethanol in it than ours does down here in Florida. I perfer 7-11 but I will also use Shell. Shell seems to give just a little less power than 7-11 does, but it gives about the same MPG. Maybe Shell gas here has more ethanol than 7-11.

The 7-11 where I usually buy gas sells a lot of gas, there are cars and trucks, police and sheriff department vehicles in and out of there all day long. I think our 7-11 gas is always fresh and clean and they keep the pump filters changed on the right schedule, and that is why I get good results with it. I have a theory that 7-11 here uses less ethanol than Shell and other brands but I have no way to find out for sure. 7-11 is usually about the best price here too.

 

[123Saab]

I have noticed no real difference between grocery store gas and Top Tier, But I'm guessing in the long run Top Tier does keep your engine cleaner.

 

[friendly_jacek]

Originally Posted By: sentra
I don't how one can attribute the 2-3 mpg difference, spread over a full tank of gas, on a change in gas brand. There are just too many other variables that should be taken into account.


+1

Recently, I tested TCW3 in gas on Prius and learned that driving the same stretch of highway (100 miles one way) at the same speed on cruse control can give you a range of 44-51 MPG (on the car computer display)!

Ironically the highest number I got was on the first tank with TCW3 and I thought it worked, but repeated testing showed average of 48MPG, same as without.

The highest variable was wind. The amount of traffic was another as the left line driving queens can screw the average speed.

 

[Durango]

My Dodge truck appears to accept any gas I put in it ranging from Arco, Shell, Costco, Chevron, Union 76 and Valero. If I'm traveling and use Costco or Valero I'll put in a bottle or two of Techron during the trip to get more PEA in the tank. No matter what brand I use my gas mileage is pretty good as long as I keep my foot semi light on the highway. In other words.... If I'm careful I can go from Los Angeles kinda all the way to Arizona all one one tank. That's 25 gallons of driving and I consider that to be pretty good. Average MPG sometimes can be 21.2 MPG.

Durango

 

[wallyuwl]

Originally Posted By: sentra
I don't how one can attribute the 2-3 mpg difference, spread over a full tank of gas, on a change in gas brand. There are just too many other variables that should be taken into account.


You wouldn't think it would matter, but I've found out over dozens of tanks in the Equinox that it does, about 2 mpg. Shell and Kroger premium gives me better mileage than BP, Thortons, and Speedway premium (all E10). My wife gets about 1 mpg better with Shell, but everything else (Kroger, Speedway, Thortons) is the same in the Vibe. She uses 87.

 

[Ken2]

Keep in mind that the formulation of the same brand of gasoline is different in different localities because of regulations to minimize emissions. One brand that is great here might be average somewhere else.

I had a job that required a lot of driving, and the only gas that was noticeably worse for gas mileage was ARCO. It was cheaper, and I should have calculated the fuel cost per mile...and I didn't. I wouldn't be surprised to find that it was actually a higher cost per mile, and that is all that counts, not the price per gallon nor the miles per gallon...cents per mile of fuel cost is what one needs to know.

 

[Durango]

Originally Posted By: Ken2
Keep in mind that the formulation of the same brand of gasoline is different in different localities because of regulations to minimize emissions. One brand that is great here might be average somewhere else.

I had a job that required a lot of driving, and the only gas that was noticeably worse for gas mileage was ARCO. It was cheaper, and I should have calculated the fuel cost per mile...and I didn't. I wouldn't be surprised to find that it was actually a higher cost per mile, and that is all that counts, not the price per gallon nor the miles per gallon...cents per mile of fuel cost is what one needs to know.


Ken2,

I've been told ARCO is the most louseyest gas in California but this was before Valero had sohwn up. Again I've used both and noticed no seen/felt loss in MPG. Perhaps in one direction the wind could be at you back and give you a push therefore helping ones MPG.

The only one time my MPG was terrible regardless of what kind of gas brand used was when I went to my annual trip to Arizona and the weather was bad. In Los Angeles it was raining and the clouds was dark so my buddy and I got outta town ahead of the storm which was following us all the way to AZ. My MPG was pretty bad as it dropped an easy 2 MPG.

Durango

 

[nickinva]

Thanks for the feedback. It could be, as a previous poster had noted, that it is a new engine. The Civic had 122K and the Subaru 56K. I forgot to mention though that the new car came with a full tank of gas, and for this I averaged 35 mpg in the first week after I bought it. I don't know where the Hyundai dealer gets their gas from, but I could ask. There's a Shell station across the street and a shabby looking unbranded one. They probably have their own supply though. When I filled up with Shell before, it was in NC and was on a road trip, so that could explain the improvement in mileage...