StreetHHR

I've been seeing some people get amazing results in terms of gas mileage. I have a 2.2 and have been getting 21.2 MPG in all city driving, A/C on or off depending on the weather. Unfortunately I can't do much about my driving style living where I live because I can't control the stop and go traffic and the the amount of red lights I run into at each corner. Is there any mileage improvement in using 89 over 87 that could possibly offset the cost per gallon?

Thanks in advance

kyhhr

DO NOT USE 87!

Sorry I know "caps" is taken as yelling but I am.
Your engine is designed to use the 89 octane. 87 burns dirtier and with less compression. Use 89 and you should see an improvement in gas mileage.

I use 89 Octane and drive both freeway and city and I get around 27-30mpg on average.

I have an 06 HHR LS with 57K miles.

solman98

I think it designed to use 87, not 89.

I've always used 87 and continue to get 27+ in town and 30+ highway with each and every tank.

twistrman

yeah, the ss is tuned to use premium (along with a warning on the fuel door) but the rest of them are made for 87.

I use 87 and my city mileage sucks, but my town is horrible for it, stop and go, all short distance, and lots of big hills. my highway is 30 though.

Clevelandhhrss

Auto or manual,

Your trips are short =3miles or less

Your idling = long stop/frequent stoplights, fast food drive throughs, cooling car with a/c before driving

You drive fast, or simply accelerate fast to a normal speed, or set cruise above 70 frequently

Your tire pressures are less than 35 once warmed up

Your dic avg speed is less than 30 over the course of a month

Pick from above, these are all more important than what fuel you use and probably explain everything. If your car is operating like it should, you should get better mileage than me. .... that is when i was Running 87 in an SS considering the 2.2 is rated at a higher mpg.

i can't speak on your specific car, but if you don't do any of the above it's hard to imagine that you'll see less than 25 to 27 mpg overall.

BTW I have never see mileage that low without really really driving like I stole it :)....... Fun though :)

GDZHHR

Actually, the SS and the 2.4 are tuned to run on 91.

StreetHHR

Auto for me and those two are probably the culprits for me.

And kyhhr, I had read the manual and it says 87 octane or higher should be fine for the engine although it doesn't mention anything about mileage so the dirt and compression could be factors in that aspect.

On my next full-up, I'm just going to use 89 and see what happens for myself...if I don't see any noticeable difference, I'm always free to go back to 87 after that

masterchief1112

dude are you off your rocker. if it wasnt made to run 87 they would tell you that when you drive it off the lot. i drive 60-40 city eway and i still avg about 30 and its on 87. heck even my owners manual im pretty sure says 87 is just fine. as for 87-89 if ive seen a difference. almost none at all mabe runs a lil cleaner. now running the 94 from sunoco i have noticed a little peppier change. no real butt dyno difference. i would say betoween them all there is a few hp diff but not alot. if its tuned to run higher octane you would prolly net more outta it.

Clevelandhhrss

I ran 600 miles on a single tank of 87 in a Shiny Black SS to put all of this to bed. I went to my normal routes, did normal things, just tried to eek every ounce when i could.
I succeeded and my SS did not go boom...lol

Nor did noice any change (mileage not power) once I went back to 94 octane if there is a difference it isnt anything i noticed. However many with the 2.4 report a small 1-3mpg difference when NOT hypermiling going from 87 to 89. The cost almost always equals out with the mpg gain. So if your "butt dyno" feels more power....use 89

You have an auto, which makes hypermiling tougher, although I went from 26 to 36 mpg overall using those tricks.

Even so assuming your just "driving normally" and you car is "operating" normally and you do live in pool-table-flat southern florida #1 and #2 are most likely (not your hhr) problem.

LOL, not to pick on you..but it is highly unlikely that you can satisfy condition # 1 and #2 WITHOUTalso satifsying condition #5 AND NOT satisfy #3(a) and or (b) and or (c).

:) Check it out for yourself.

an08HHR

Out of the 06 owners manual:
If your vehicle has the 2.2L L4 engine (VIN Code F),
use regular unleaded gasoline with a posted octane
rating of 87 or higher. If the octane rating is less than 87,
you may notice an audible knocking noise when you
drive, commonly referred to as spark knock. If this
occurs, use a gasoline rated at 87 octane or higher as
soon as possible. If you are using gasoline rated at
87 octane or higher and you hear heavy knocking,
your engine needs service.