mudbilly

I was browsing thru the owners manual and discovered that they recommend 91 octane for the 2.4l motor.............being the cheapskate that I am, I was wondering if anyone here has been running no-name 87 in their car?

I'm almost ready for my first fill up

SoCalHHR

You will get better mileage and performance by running premium in your 2.4L.

Tthere are several threads already on this - do a search, there's plenty of reading!

1BadPig

Butt Dyno says premium gives more performance but calculation shows little to no benefits on mileage.

SoCalHHR

Just a tip: if you are getting better "performance" you are not getting better "mileage."

Answer: Keep your foot out of it.

Then you will see mileage gains with premium.

glenngeb

What about using an octane booster, sold in most part stores. I used it on a 2001 3.1l Malibu and went form 24 to 30 mpg. Afraid to use it now as I only have 250 miles on my HHR

crowbar

i run the cheapest crap i can find in mine, never had any problems 6000 miles later

wolfee

Crowbar, I haven't got my hhr yet and dunno if I want the 2.4 or not. I am astonished they can run a 10.5 compression motor on your "cheapest crap you can find". Do the sensors and microchip just detect the crummy gas and adjust the spark accordingly? Do you EVER hear any knock at all?

crowbar

ive never heard any spark knock and never noticed any hesitation. i also have a 04 yamaha r1 with a bunch of engine mods and unless im expecting to race someone i run cheap gas in it also with no problems

GDZHHR

I get about 2 mpg better with premium.

Did a little math and by using premium, I'm saving about $1.60 per tank using premium over regular.

nfboy

I'm on tank 4 now. 2 have been 87 octane regular and 2 have been 91 octane supreme. Can't say I notice any difference in performance or mileage but time and testing will tell. Next tank will be 89 mid-grade.