I have no concern for performance. I didnt by the car to go race with or burn up the roads. I bought it to transport the family. As I said before I have another car that gives me the fix of speed and power I need.

I just want to make sure I dont shorten the engine life and make it last as long as possible. I did RTFM and you are correct that is what the manual says, however I looked was looking for real world experience.

GM is not the all mighty all knowing IMO. Hell there is no way I am gonna let my car go beyond 5000 miles on the oil change, but thats just me.

 

It sounds like you answered your own question afterall. Enjoy the savings and live without a few ponies.

 

I've owned two cars now that were "premium optional". My '99 Cadillac Catera ran rough on 87 and super smooth on 91 (that's what we have here). Mileage was the same and performance was only marginally better. So I compromised and ran mid-grade. My dad has the car now and only runs 87 in it. It has 110k on it.

I've found the HHR to have better performance at freeway speeds and slightly better overall mileage running 91. Cost ends up being a wash with the mileage gains. So I run 91 all the time. I like the extra punch on my daily 25 mile commute. It does not run rougher using 87. If you chose to use 87, you will not harm the engine in any way. However, REX347, I would encourage you to try it for yourself, don't just take our word for it. Run premium for a month and keep records of the results. Do the same for a month of regular. Do the math, then decide. That's what I did and why I use premium in my HHR.

CrazyCarKid, the G6 has the same block and head, but it is not tuned the same. The 2.4 in the HHR has more torque and more HP than the one in the G6. Granted, its not a lot, but the numbers for the 2.4 in the HHR are based on the use of premium fuel. The G6 would not benefit from 93 because it's not tuned to take advantage of it.

 

I've been running mostly 87 octane in my 06 2.4L auto. I did exclusivly 92 octane (91 isn't avaialable around here) for 2000 miles and saw no difference in mpg to justify the 20-24 cents per gallon price increase. There was some better acceleration using the 93 octane, again not enough to justify the price increase since my driving habits don't involve high speed driving/drag racing etc.

 

I noticed much better fuel mileage with 93 than with 87,slightly better with 93 over 89. Surprising to me is the fact that the performance isn't noticeably better.My car is somewhat sluggish from a stop no matter what gas I use.The thing just doesnt have much vigor until the tach hits about 2800 r.p.m.That's partially explained by the fact my car is a 5 speed so it doesn't benefit by the torque multiplication of a torque converter.

 

I've tried 87 and 93 and personally I seen no difference in either rating. I'll stay with the 87.

 

I tend to trade off every other tank or so (87 & 93). I haven't noticed any better mileage, (haven't really checked) but I've definitely noticed a hesitation from a standing start with the lower octane.

 

I've got the 2.4L L4 engine code V. The manual is quite ambigous about fuel:

If the vehicle has the 2.4L L4 engine (VIN Code V) or
the 2.0L L4 engine (VIN Code X), use premium unleaded
gasoline with a posted octane rating of 91 or higher.
You can also use regular unleaded gasoline rated at
87 octane or higher, but the vehicle’s acceleration could
be slightly reduced, and you might notice a slight audible
knocking noise, commonly referred to as spark knock.

I only have 160 miles on my car with with the exception of 4.5 gallons of 89 octane I have put it, it's been running on the first tank from the dealer. I don't have any knock and will probably continue to run on 89 octane. What worries me is the statement about California fuels:

If the vehicle is certified to meet California Emissions
Standards, it is designed to operate on fuels that meet
California specifications. See the underhood emission
control label. If this fuel is not available in states adopting
California emissions standards, the vehicle will operate
satisfactorily on fuels meeting federal specifications, but
emission control system performance might be affected.

I am having to move to New Mexico because of work, and have no idea about what type of fuel they have in that state....

Fred

 

90 octane (proof) tequila.

 

I bet there are thousands of cali cars being operated in other states with no problems whatso ever..Your emissions have a wide operating range..you'll still pass, though "readings" may be different then cali. Besides..I bet the gas is actually better. Cali gas is about whats at the tailpipe, not whats at the rear wheels.....\
Whats the chance that about the only difference between the instate compared to outstate is the tune....