If you look in your manual, I think it recommends 91 octane fuel. You may get better mileage from the higher grades of gas. I tried it once so far with no immediate results (only 2000 miles so far). I'm used to old Saabs, if you ran the premium gas , you got better milage, usuually better enough to offset the higher gas price.

 

Hmmm - do you have HID's? Those things are known to take a little bit to light up. Now that you mention it... I did notice a hesitation between when the highs go off and when the fogs came back on... but I didn't notice any "dark" time.

As far as the premium gas... if you look at the cost differential between RUG and PUG, unless the mpg delta is friggin' amazing, I can't imagine it being worth the extra $$$ at the pumps. But... what do I know? Higher octane is not supposed to be more potent; it's only supposed to be less prone to pre-detonation for higher compression engines.

However... if some gas has ethanol in it and some other gas doesn't, that can make a huge difference. Ethanol isn't near as powerful as gas... which is why the move to E85 makes no sense to me - costs more, burns food, and doesn't result in near the mpg's of good 'ole gasoline.

But... if the GM 'injuneers' programmed the PCM to check the gas on-the-fly and de-tune the engine for 87 octane gas... then maybe that's contributing to the situation. Does anyone know if this is the case? I'd really like to get more than anectdotal evidence of this...

 

I have an 08 2.4 auto 2LT. When I picked it up it had 60 miles on it, now 1220. 99% of my driving is in town and about 10 miles a day. My best mileage so far has been 15.9. I drive it conservatively and mix it up with the "whip effect" and a few banzai runs.

I, too am concerned and mainly because I read all these varying reports of mid 20's MPG. A friend has an 07 2.4 and he drives the piss out it and gets 23 average. The dealer told me to put another 1000 miles on it and monitor it. These cars do not have fire breathing ponies, are rather heavy and have 4.13 gearing. I hope mine goes up. What is the recommended octane?

 

Think the book indicates that either fuel is OK. I'm going to try both and keep an eye on it.

The blackout with the lights occurs when going just from low beam to hi beam. Try it sometime and see if everyone's does it. I have the standard lights that came with it. Also, I'm not really impressed with my high beams. They don't throw off a lot of light. Anyone gone with something better?

I don't like the blue lights. They blind you if they're coming at you. Can tell an Audi or Lexus a mile away. Think they're illegal if they don't come standard on a car - not sure.

 

I'll watch for it. BTW, I've been goofing around with the lights on my truck, and I'm starting to be happy. I too think the highs on the HHR stink... the fogs do too, for that matter. But... at least you get fogs and low beams together.

I've got a couple of diodes tying my highs, lows, and fogs together in my truck. The result is that my lows and fogs work independently... but when I go to highs, all three are on. Plus... I switched out my standard fog bulbs with Silverstar's. I will tell you... the combination is bright! But... I'm not done. I'm eventually going to replace my lows and highs with HIR's - they're essentially a reflected hallogen - which is supposed to be really, really bright.

I would think that you could upgrade to Silverstars, though they tend to be a little blue (not ridiculously blue like some of the "ricer" racer guys have in their cars). It's not too bad if they're just in the fogs (which is where I have 'em in my truck). They are 100% legal and run about $20 each at your local parts store. WalMart even carries them. I have heard some complaints that they burn out too fast, which is why I only have 'em in my fogs. They are bright.

I think the HIR's are simple drop-in's; a tad bit of trimming to get the base to fit. They are very bright - supposed to be 75% brighter than stock - and run about $25 per bulb, available from a dealer out on eBay. You have to be sure you're getting the real Toshiba HIR's though... there are bogus knock-off's you have to watch out for though. Search for "HIR headlights" and make sure you are searching the title and descriptions.

Not sure if the "all headlights on" mod can be done to these cars or not. Now that I know how to do it (2 diodes is all it takes), if we keep the car, I'll probably look at trying to do this.

HID's are another thing altogether. They require ballast and different wiring; plus, to get a good set, you can spend as much as $200-$400. Out of my league at the moment for either the truck or the car.

Just asked my wife... and she confirmed the brief blackout between lows and highs. Guess I just don't drive the HHR often enough to notice.

 

I have the 2.2 & only drive city so far (like a leadfoot) so I can't really comment... but I am geting 23.

I can't believe your old van conversion & 4X4 got anywhere near 22 MPG. Seriously?

 

Our 2000 Chevy Express van (raised roof, fully customized) used to get 18-19 mpg out on the highway. I did not say that I got 24 mpg in it; I did say that I was hoping to vastly improve the mileage by getting the HHR, and I did say that I only improved the mileage by 3-4 mpg.

My 4x4 Chevy Silverado w/Duramax diesel does get 23 mpg on the highway. It's modified just a bit (CAI, Predator economy tune, etc); it did not get above 20 mpg when it was 100% stock. I know of several guys out in the diesel arena that are getting 25-27 mpg. I'm hoping for 25 after a couple of more mods. The tough thing here is that the more mods you perform, the harder it is to keep your foot out of the accelerator. BTW, one of the fastest Duramax diesels out there puts more than 1000 rear wheel horsepower down, yet gets somewhere around 34 mpg on the highway. Then again, he probably has in excess of $100k in his truck too. Oh well...

 

Stock wheels and tires? If the tire size is diameter is different it will skew your odometer. Spark plugs maybe?

 

Are you sure that you are calculating correctly. If the DIC says 31, its probably correct.

 

Some cars turn off the lights while switching... I'm guessing to make things easier on the poor bastard you're blinding before dropping down to low beams.

I haven't used my high beams yet (all city so far), but I'll let you know if it's too long of a pause to be safe on my HHR.