dalek

Is it a pipe dream to run an '08 HHR with 2.4 engine on 87 and get decent fuel mileage? I have been using 91 since I got it last fall and getting upper 20's on road with K&N air filter the only thing done to it. I travel Kansas and Oklahoma and I know my mileage drops in the wind we have out here. Thanks.

JavaMann

There's lots of variables that go into mpg, but for what it's worth, my 2008 2.4 on 87 octane gets 25-26 in town and 29-32 on the highway. I drive like the old fart I'm getting to be, lol.

ronp

I see no change from 87 and 91 I get 28 to 30 highway at 65 mph and up normal highway driving. just stay away from the E85 I got 14 mpg.

SS fan

I have a 2.4, ran 92 in it for a long time. Tried some 87 and it gets way better mpg with that, a touch over 25 average because I am always carrying a load. I have the K&N intake and a Trifecta tune.

Old Lar

After 111,000 mile in my 06 2.4L HHR auto, I've been running 87 octane most of those miles. I experimented with 93 octane (2000 miles) and saw no improvement in mpg. Just a lighter wallet. I have averaged a tad over 30 mpg in the seven years of ownership. Max was 38 mpg, the worst was 21 mpg.

mpg is related to how heavy your right foot is. I use cruise on the highways and a light foot other times. I try to get the transmission into lockup as soon as I can which is about 40 mph and 1600 rpms.

DaGrinch

On my '08 2.4, I would get between 27-28 mpg on 87 octane in the mountains of Western MD. Get out of the mountains and it was consistently at 30. City driving was around 24-25 mpg on the 87.
But, like JavaMan, I, too, am starting to drive like the old man I am getting to be - especially after hitting 60 last week!

SS fan

Happy birthday Grinch, I had one last week too.

sleeper

Hapy Be-Lated Birthday- DaGrinch & to SS fan..

Mine is last week of this month.. coincidence ?

PS: I also get better gas mileage on 87, but more fun on 93

finnhhr

We have used with -08 hhr 2.4 ours MON 95E10, which is around RON 90 in US octane,for long time and no harm done, but we dont get so good mileage between fillups. That also affects that currently is freezing around 5-10F... Our more in town-like driving FILL-UP average is around 25MPG.
HHR´s like all modern cars have knock sensors, if the gas quality gets too low it will knock for sure. But if the manufacturer recommends premium91 why not use it- one SHOULD get better mileage with it...

But i use at my -91 dd buick ours "MON 98E5" (REAL premium in RON´s), cause it has less ethanol in it and if my old beater gets even 1 more mile or 1 more hp with better gas, i buy that premium gas. I drive more highway roads with my old buick and it gets around 22MPG between FILLUPs.

difference in simply is like this
EURO "regular" MON 95= (RON 85 + MON 95/2)= RON 90 U.S.A.
EURO "premium"MON 98= (RON 88+ MON 98/2)= RON 93 U.S.A.

Why they count the octanes different way, i have no idea... sorry to go slightly Off-topic here...

dalek

Thanks for the info. I have been running 91 since I bought it last fall and was thinking I would go with 87 since I don't have a real heavy foot. I'm over 60 and don't drive near as hard as I used to!!