After reading through several of the gas mileage posts, I'll add my 2 cents worth. My '07 Fit sport automatic has 8500+ miles on it. I've recorded in a spreadsheet every fill up which includes date, vendor, miles, and gallons. I have it set up to calculate the mileage for each fill up and overall average to date (32.41). What I've seen is, when using a non top tier gas, my mileage may fall as much as 10% for that tank full. Normally, I use Qiuk Trip's (DFW and/or regional conv. store/gas station) gasoline as it's the only non major brand ( such as Shell, Exxon, etc.) that adheres to the top tier guidelines that I'm aware of and it's usually the cheapest in the area as well. You can google top tier gas for more info.

 

I've seen my best mileage come out of fuel from Citgo. Supposedly, the Venezuelan oil used in the making of their fuel is of much higher quality than that from the mid-east. I don't know this for sure.

But, even so, I don't get noticeably bad mileage from the mom n pop gas stations around here either.

 

The only difference between gasoline brands is additives. The base fuel in "fungible". When Citgo (or any oil company) ships a load up the pipeline, they simply put a load in the pipe and take a load out at the destination, they do not get the same fuel out that they have put in.

 

I started looking into gas types just recently after reading about how other people's mileage was differing so drastically. If you have a graph that correlates mileage to gas companies, that would be good to share. I only recently started and do not have anything yet.

I've been using NEX gas here in San Diego (don't know where they get it from) as it has been cheap and reliable as far as water in the gas goes. I've been averaging 32 mpg. When I started reading about ethanol mixes being different between gas companies and how poorly ethanol works in low compression vehicles, I decided to try different gas companies and graph the findings.

 

Didn't Citgo discontinue business with Venezuela recently?

 

The specs for gasoline are rather loose (a major complaint of auto companies trying to meet ever tighter emission controls) and refineries are always working to get more gallons of gasoline out of a barrel of oil by cracking and re-combining molecules. It is very likely some refineries are giving you fewer BTU's per gallon than others.

Also, Top Tier specs include additives and require a 10% ethanol component per their website. Ten percent ethanol blends have 4% fewer BTU's per gallon than straight gasoline. So, non-top tier gasolines could produce a 4% fuel economy improvement (if ethanol is not required in your area).

 

Well, my study is going slowly as I have only tried one other gas company so far. I've been using NEX gas and tried two tanks of Shell low octane. That gave me a drop of about 2 miles per gallon. I was surprised. Same driving habits, to and from work.

Went back to NEX gas and picked up my 2 mpg back.

Not sure which company to try next.

 

NEX as in Navy Exchange? On my base i wont fill up unless i absolutely have to. The two gas stations we have suck and i get 2 to 3 mpg lower then when i get chevron fuel. I use the same gas station and even same pump if i can. Same with all my trips to Georgia i hit all the same chevrons and use the same pumps if i can. I can get 37mpg doing almost 80mph the whole way down there. Junk gas i get 33 or 34 but either way that is still better then my Z71 ever did so i cant complain too much. haha. But yea back on subject i swear by top tier but thats my personal opinion though. I also only run mobil one oil too.

 

All Shell gas stations in Florida are now owned by CircleK. That Ive noticed.
I only; and will only use Chevron in my Fit.

 

ive been using arco :/
not the best brand i hear but its right next to work and i guess im just lazy chevron tho, most ppl live and breathe off chevron..WITH TECHRON!!

 

shell/mobil/76.........

18k miles.......get about 29mpg.....

i used to get about 30-32mpg........

 

Yup, that's the one. Here in San Diego, it seems to be pretty good. I've seen bad NEX's in other areas, though. The one in Japan had really bad gas, especially after the tanker came and reloaded the station. Must've had a lot of water down there because if you were filling up at the same time that the tanker was reloading the station, the cars would really begin to run bad. Any other time, the gas would be fine. There were a lot of complaints about it and they had a captured audience. Off base gas in Japan was ~$4 a gallon, but on base, it was <$2 for along time. I hear it has gone up a lot recently.

NEX usually ranks as one of the cheaper stations in SD for low octane.

I'll try Chevron next.

 

Im at Cherry Point, NC and the gas is usually cheaper but it doesnt agree with my fit too well so i will just pay the extra couple cents and get the good stuff so i get the better mpg. My Z71 though i only filled it on base cause it would run on damn near anything and when your putting 28 gallons in every cent counts. haha. God im happy i dont have that monster anymore. Lol!!!

 

I try to only use Top Tier retailers. I mainly use Quik Trip since they are among the cheaper gas stations. Other than that, I use Shell, Chevron, or Texaco. On rare occations will I use Exxon.

At least we know Honda is among the car manufacturers that recommend Top Tier gas stations. I want to pay my car off and try to keep to for a little while afterwards.

 

Well, after going through a few tanks of each, Mobil and NEX gas run the same. I get the same pedal feel and mileage. I wonder if NEX is getting its gas from Mobil.

 

Here's Edmunds' take on different octanes and brands. Here's an excerpt:

In Edmunds' forums some drivers expressed concern about the quality of gas sold at independent gas stations and advised sticking to the so-called "name" brands of gasoline.

"Typically the only difference is the additive package they put in the gas," Beard said. The additive package is often put into the gas as the tanker is filled up at the refinery. A common additive is a detergent agent. "The law requires a certain level of detergents in gasoline. Shell, for example, is putting in more detergent. — Whether that has a measurable effect to the driver is debatable."

Detergents have a marked effect on engine deposits. "If you take apart a modern engine that has been running on a modern fuel, and compare this to an old engine that was running on old gas, you can see an obvious difference," Mazor said.

Read the full article here:
Do You Really Need Premium?

 

Yes, gas is gas until they spray each brand's additives into the tanker as it's being filled. I never knew that until I read "Oil on the Brain: Adventures from the Pump to the Pipeline" by Lisa Margonelli, pretty good read.