Gas Octane

Badger, Creemore and others - I ABSOLUTELY get more mpg out of 91 vs 89. Now, it very well may be because I use eth-free 91 but that's because eth-free 89 or 87 is illegal in this state! So it's not always as cut and dry as you might want to believe. I get 18.5 on 89 and 20.4 avg on eth-free 91. Both numbers calculated over 10+ tanks, summer and winter gas.

 

Yep I second that, and driving empty not towing anything I've gotten 27.5 mpg driving 53-55 mph. Flat ground no wind.

 

only filled about 6 times, but I drive very consistent routes during my day, and I notice a very clear 1 mpg difference between 87 and 93, or 87 and 90 NO-E.
3 tanks with 87 were all between 16 and 16.5. Each 93 or 90 fillup was between 17 and 17.5
With a 20 cent price difference that makes it a draw.
Literally, YMMV

 

Sorry, I was responding to the power thing. I believe you on the fuel economy. My own experience, over about 100 tanks (iPhone app) is that premium us just over 1 mpg more economical. I live in a hilly area. The thing is, premium is SO much more expensive in Canada that I wouldn't bother trying to make an economic case for it

 

Right on - what's the premium...premium that you usually pay? 91 fluctuates here - sometimes 20 cents over 89, and sometimes 30 cents over.

 

I've used 93 the last couple tanks because I've been getting pinging under acceleration. Gone. I used it quite a bit in the past and I've noticed approximately a 2 MPG difference from 87 to 93. Our 87 is 10% ethanol so that may very well be the difference. Whatever, 93 is working fine for me. Maybe I'll get it every other tank.

 

It works works out to 57 cents per US gallon. Arrrgggghhhh....

 

91oct. I pay more, but I end up going farther on each tank of gas. so it ends up equaling out. And if it's better for the engine, hell, why not! lol

 

I use 91 without ethanol. I have a place on my way home from work that will never use ethanol. We put in the wifes new Grand Cherokee and it runs better on it as well even as a flex fuel.

 

Anyone here in DC metro area (MD or VA) that know of anywhere to find ethanol-free gas?

I'd prefer to use it, but I haven't been able to find any in quite a while...It's pretty much E-10 across the board unless I head to the shore and find a marina.

To answer the OP, in this area most places carry 87 and 93 and *either* 89 or 91, which is what I generally use.

 

http://pure-gas.org/index.jsp?stateprov=VA

Try this site out Pete. Will tell you the station by city in VA. Just change your state for where you want it.

 

Thanks, I have seen that site. Problem is that I'd have to burn a tank of gas to get to most of these places!

When I think about it, I usually check this site when I going camping or just on a road trip in general, but it's almost impossible to find ethanol-free fuel here near the city for my everyday use.

 

93 cause she's my baby

 

On average in California 91 octane is .20-.25 cents more per gallon than 87 octane. So if you put 20 gallons in when you fill up then it will be $4-$5 more every time you fill up your truck if you use 91. 87 octane fuel goes for about $4.25 per gallon in Northern California (cost could be more or less depending on where in California you live). That means that you would need to average about 1 more mile per gallon using 91 to break even financially in my area.

Personally I use 87 most of the time and 91 when I'm towing. The engine seems to struggle a lot less when I use 91 when I tow.

 

My 3.4l runs best on 87 or 89 at the most. 93 makes it run worse and decreases the fuel economy.

It depends on how the ecu is programmed and elevation makes a difference.

 

thought it didn't make a difference but after use 87 octane for a while it seemed like the truck was being held back and not running at 100%, everytime I get on the freeway I would have to mash the pedal to the floor just the get it going, but after I went back to 91 octane, I no longer have this problem.

 

Call me crazy but,
Theres 2 particular hills around here ( on highway) where truck will downshift to 4th with 87 oct. to maintain cruising speed, but with 91 it has nuff nuts to do it in 5th.
Bring it.
I will drive on fumes past 6 gas stations to find a Shell.
I like it a lot.

 

I Ran 87 once and the truck was pining and the mpg was 13 to 14 with no mods ...terrrible. Now constantly run 91 which is less than 2.00 more for a full tank and no pining and 18 to 19.5 mpg in summer ... a lot better.

 

91 everytime, seriously its only like $2 more for a whole tank!

 

Here in Knoxville TN we generally only have 87, 89, 93. I recently switched to the 93. Engine sounds much better when pulling, seems to run a little smoother, and maybe a touch more power. Cost about 10% more so if I can get 1.7 to 2.0 more mpg, then it is a wash cost wise, and has to be a little better for the engine. You did not have a 93 in the poll so I did not vote.