i usually fill up at the citgo here... which is usually the cheapest... but lately ive noticed when i fill up at mobil or exxon i consistantly get about 4-5 MORE mpg per tank... (doing the same driving)... of course mobil/exxon is usually 7-8 cents more per gallon... but the few cents extra per gallon actually ends up saving me money in the long run because im getting like 31-33 MPG (about 350 miles between fillups)... im not sure why this happens... maybe the citgo just sells crappy gas??

 

maybe mobil is better?? some places use that detergent gas or something that is better for your engine i think, but i always that gas was pretty much the same, but who knows maybe not

 

yeah i always thought that gas was gas and thats it... my dad says mobil is supposed to be a detergent gas maybe thats why

 

I avoid citgo as much as possible, it has always given me a lesser mpg

 

Detergent gas? Haven't heard of that here. I'd check to see if these Citgo people were being a bit liberal with the ethanol.
What octane do you guys use? I fill with Premium/98oct

 

The US RA is designed for 87 octane, which is what most of us use. I've never compared MPG between brands, though.

 

98 Octane?

 

he's in australia

 

i use 87 octane

 

I used to use 93 until gas went ballistic. Then I switched to 87. That's what I use now.

 

Oh okay haha. I use 87 Octane from Canadian Tire, since i get $0.05/litre back

 

This is my prognosis. I have been silly with gas like that ever since I had to run straight premium on my turbocharged Mirage. I would compare gas from different companies AND different stations to see if it made a difference.... and it did.

I found that gas from the "blue" gas stations usually was better than the Citgo / 7-11, Raceway, and all the el cheapo gas stations like WalMart, Sams and all that stuff. Usually Exxon, Chevron, Mobil or Amoco used to be good (since Amoco went to BP, it wasnt the same). Anyways, since I moved here to Orlando, I was patronizing two of the more reasonably priced gasstations, one an Amoco, one a Mobil. Same price for the 89, but the Mobil, I would get close to 300 miles per tank and this with a lot of spirited driving and 95% city driving. I would average between 26 and 28 depending on how aggressive I drove. The same Amoco, I would get 25mpg regardless.

Back when I was in the Tampa Bay area, there was a run down Chevron with cheaper gas but the 93 used to give me less mpg and seemingly less oomph and more detonation than when I was using the gas from Mobil or Shell. So who knows.