I've driven my 2004 Prius nearly 50,000 miles and have tried almost all available brands of regular gas. Strangely, there seems to be a significant difference among brands even though my driving (over the 300-400 miles to a tank) doesn't vary much. With some brands MPG isn't much over 39 mpg for the tank, others get me 48-50 mpg. Interestingly, the best mpg comes from a little no-name local station...

Anyone else notice a consistent difference?

Thats interesting. I wonder if the additives the big companies put in take up volume and therefore reduce how much power you can get out of the gas.

Any of you guys in the industry know if this would be the case?

It could be that short term the no-name stations are good but in the long term using the larger named brands will keep your car running more efficiently.

My hydroponics experiment

You ever notice how hard it is to lip read cartoon characters?
"Crazy is what the sane call Delta Flyer"

I almost always buy citco gas (because its usually the least expensive) and for the first 3 tankfulls i was averaging about 51 mpg. My last tank i put in Mobile (always regular) and noticed that my milage has suffered back to about 48 mpg. However the weather has gotten about 15-20 degrees cooler which has an even greater effect on milage, so who knows if its the gas or the cooler weather.

Mr Bosox has used everything from exxon/mobil to citco to Sheetz (which is my favorite) ---- most do well, but i have found like another post that the little no-names do the best--- crazy huh? yep j from Virginia.

Mr. "Salsa" Bosox

The only time i've noticed is when I go to a station that mixes ethonal in their gas, then power drops and mileage suffers. Other than that, no.

i was going to say the difference could be the pumps not the gas, but then i remembered our cars calculate our mpg for us and the pumps wouldn't make a difference.

This post mentions a toptiergas that Toyota was a part of. One of the sepeculations put forth in the thread is that since it's gasohol the toptiergas will lower your mileage, although may keep your engine cleaner.

Best commute RT = 27.5mi @ 90.5 MPG (sg2)
Best (non-trivial) tank = 665.5mi @ 72 MPG (fcd)
MPG Centurion - Hybridfest 2007 - Prius II - 26mi @ 106 MPG (sg2)
Dan <11011011> @ CleanMPG.com

Newbie here. Getting my 05 Prius (pkg 6) this week hopefully. The only difference in the gasolines is in the additive packages which have stabilizers and detergents to keep the gas fresher longer, and to help keep the intake system and combustion chambers clean. In general, always buy your gas at a location that sells a lot of gas. This way it will be fresher and you should get the best mileage.

Rich

I don't think fresher is the right word by I get your point. Stations that have high volume have tanks that are constantly being used and filled... which in turn keeps moisture down. Water in gas is very bad... and high volume stations keep that at a minium.