Yeah, she'll run fine on 87 or 89.... but you'll lose some HP.... and therefore you should get worse mileage. If an extra 10¢-20¢ a gallon makes that much of a different to your wallet then please fill up with regular. If you do... do us a favor and let us know the mileage you're getting off of a tank of regular too.

 

No offense taken SilverStreak. I actually doubled checked right now and it read 28.8.

About a month and a half ago I drove to New York and right before I left I reset everything. I was got over 30mpg on that trip. Tank and a half to get there and a tank and a half back home.

I reset my trip everytime i feel up and it's always between 290-305 miles. I drive 30 miles round trip to work. 3 lights on my way there but i rarely hit them when they are red.

 

Yeah, I'd totally believe 30MPG on the highway, certainly.

 

This is my wife's car. It's now at 1900 miles and she is still getting 26.4MPG on 87 octane.

 

Actually, the additives that increase octane do absolutely nothing for the energy content of the gasoline. All they do is make it more resistant to pre-ignition. When you are cruising along at less than WOT, the timing is no where near fully advanced and there should be no measurable difference in fuel economy.

 

21-23? You sure? I run 87, the cheapest gas I can find and I got 330 miles out of the tank before last fill up and I still could have gone another 40 miles before I needed to fill up.. I just had things I needed to do :P. I haven't ran my SS on 89 or 91+, but if it's better than 87, you should be getting around 30 MPG. I get 27 mpg off of 87.

 

As long as you can get a consistent grade of gasoline, 87 is fine. I run 87 here in Vancouver and I always get my gas from Chevron (I know some of the states have Chevron gas stations.. but not all). For all you guys in the US.. try Texaco 87 octane. Haven't had any problems with my mileage.

I've had bad experiences with Esso/Exxon gas before.

 

I always use 93 octane.... I don't want to have the horsepower potential of this engine go to waste. I also drive in horrible city stop-and-go traffic.... so yeah, 23 is the best I'm seeing.

 

I have 4500 miles on my car and i only get around 20-21 mpg, never had any higher

 

Even though I dont have the 2.4, it took my 2.2 a good 10000 to really break in. I have 20000 on my Cobalt now, and im getting around 32mpg overall. Just give the engine sometime to break in and you will see your gas mileage improve.

 

YEah, exactly. I am well over 13000KM now and my mileage has improved a lot.

 

You must have a pretty heavy foot then.

Shifting at 2k-3k RPM and keeping it under that range for the most part, along with avoiding jack-rabbit starts, blipping on down shifts, high RPM downshifts, etc are the only way to get the rated fuel economy.

 

I'm getting 8.7L/100km with 30 min hwy/25 min city driving per day on 87 octane. I punch the throttle when i'm pissed off with traffic and I have to take a side street shortcut or passing some idiot doing 30 in a 60. I just hit the 4000 km mark too

 

im only getting like 17mpg in mine with 700 miles on it

 

Today I got the best gas mileage out of my SS....when I got home after filling up the tank I checked the little computer thingy and it was saying 8.6l /100km!!!! WOW!

_________________________
2006 Cobalt SS 2.4l BLACK

 

Damn son pull your foot off the gas.

But i get about 23-24mpg with 1400. But thats with driving it semi hard as two jobs during the holidays is hectick and it seems like everyone no matter what speed drives in the left lane . Also thats mixed highway/city but i do about 80 on the highway so that hurts it a bit.

 

My fuel economy has actually gotten worse over time with the 2.4L VVT. However that's easily explainable. Around 2500-3000 miles the engine finally became really broken in. It revs far more quickly and smoothly then it ever did. It's been very hard to not want to make this engine go ***** to the walls all the time.

Also up until last week the weather has been perfect so I've had the top down all the time, and that really kills my fuel economy by like 3 mpg instantly.

 

I drive an 06 SS/SC 140 miles roundtrip to work every day. I average on the week between 28-32mpg. I dont drive like a grandma, but I also dont get on it at every stop light.

 

I was getting 28 while it was warm out. Now I'm getting 25.5 since the temp dropped below freezing.