I appreciate all the feed back. But it seems that people back east get better mpg's. I was told that fuel in Ca has way to many additives to combat emissions. I did notice that one time when I filled up Yuma Arizona I did get more miles, but assumed nothing of it. I need to figure out to get at least 420miles and not drive like old lady.
Thanks everyone!!

 

Well'll I'll bite. I've been filling up with reg unleaded for 5 months now. I'll let it run out and fill it up again in a couple weeks and see what it reads. Right now its around the late 370ish area

 

I usually fill up at 400-415 or so. I always leave 60+ miles on the range so I don't end up walking. That works out to about 29mpg. The longest i have gone is 515 using 14.25 gallons. That is around 36mpg. 87 or 94, no difference by octane.

 

Please show me something, FROM A RECOGNIZED PUBLICATION, that substantiates/supports the HHR can determine the type of fuel used BY PHYSICALLY ANALYZING the fuel.

 

don't be a bully snoop-dog.

LOL

Anyway, can we put this to rest already. For mileage, 94 or 87 it dosen't matter. I say it again, I GET BETTER GAS MILEAGE THAN YOU WITH 87 octane. In c-town we have 94 at the pump, I use it sometimes, when its real hot and I'm carrying 3 other people and luggage and I want to show OFF. Other than that its a waste of money.

I want you to buy whatever you want, it's YOUR hhr. But that won't help mileage. Sorry charlie, I've had too many 515+mile tanks to STILL BELIEVE THE HYPE. If your not in an SS and you have NO BOOST, that it is a HUGE waste to get anything but high quality 87.

And please in whatever response to this post, do not use the words KNOCK, SENSOR, RETARD, TIMING, BREAK IN PERIOD, or the like. You will still be wrong.

I have been crusin at an average of 20% greater mpg CITY and HIGHWAY than the sticker since mile 500 (took that long to use the DIC inst mpg) until today at Mile 5342. Still reading 48% oil life.

 

Slight clarification. The energy content of the fuel (btu/lb) CAN vary with octane, sometimes up sometimes down. High octane race gas with high Toluene content yields better MPG. High percentage of Ethanol raises octane, but lowers energy content, so you really need to know the make-up of the fuel in your state to conclude with certainty that octane does not affect mileage. Cleveland sure got a good one, I can't even come close to his results.

 

My last fillup (today) I had covered 424 miles and put in 14.42 gallons and spent $57.01. I notice though, that the ethanol blended gas drops my highway milage from 32 mpg down to 29 mpg.

 

Sorry if I sounded like a "bully". But I absolutely cannot tolerate people that "stretch the truth" and apply it with such conviction that others will pass it on as truth . Absolutely unbelieveable.

Now if I'm wrong about the above assertion, I will apologize AFTER some documentation is provided. And it's still unbelieveable

 

I don't disagree, but remember, if your car can't tell what you put in it, it can't take advantage of it. If i put rocket fuel in my car, my mileage wont get better. The "retard/timing/whatever" only works in a tight limit. It won't retard enough for me to run 85 octane for example, or advance enough for me to get better mileage out of gas higher than 91 with out a tune. Also without sufficient load, oxygen depravation, temperature, WOT etc, the HHR wont distinguish between 87-94. I should have added (btu/lb) to my do not respond list of words.

You have a tune c2vette, so you probably can take advantage of 91+, and probably can't run well on 87, YOU TELL ME, I'm still stock, and lusting after you BSR/HAHN/PPC lol

 

Ummmm.....earlier in this thread someone mentioned 98 octane. I have never heard of an octane rating that high in ordinary motor fuels.

Was that a typo or is there actually 98 octane gasoline?