I am in the market for a HHR SS I really love the looks of them and I had one out and took it for a ride. I noticed on the inside of the gas filler cover it said premium fuel recommended and I asked the salesmen about it if you did not run premium fuel in it if it would cause any problems, he said it would only could a lose of horsepower and not cause any motor problems. I was wondering how many of you out there are only running regular fuel in you SS. I own a 2008 Pontiac G6 GXP and I will be trading it in on the SS if I go throught with the deal of getting one. The one I took out for a ride was Black on Black and the only option on it was the Automatic Trans, looking over the options there are very few you can get on them. In this area right now there is about $4000 in total rebates and incentives that can come right off the top of the cost. I am new on here so thanks for any of your replys.

 

I wouldn't use anything lower then 91 octane on the factory tune for the simple fact the factory tune knocks even with 93 octane. I'm sure others on here would disagree and say to use 87 octane (I just wonder if GM could turn down warranty work if you had 87 octane in your tank when it says to use premium).

 

X2. My tech writer and Chevy Tech guy both own Turbo cars and have given me the "premium only" lecture. The fuel efficiency overcomes the pennies is cost differential.

 

I never put anything under 91 octane in mine (I usually run 93), even before the stage kit was installed. Now I have to.

But there are some in our group who have done some comparative tests and found that the fuel economy dropped with lower octane.

You might want to do a search to resurrect the thread.

 

91 octane or better since day 1.

Manual States:

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 figure, it's about 20 cents more per gallon... at 16 gallons that's $3.20 a tank if you are completely empty... For $3 a fill up, I figure it's worth it. Besides, many fuels have more additives and cleaners in the premium (Shell and Chevron both do I know for sure)... You can't buy a bottle of that stuff for $3, but it comes in the premium, so I like using it as a cleaner to clean out the injectors and all...

 

I think it's more of a customer satisfaction and driveability issue. If the octane is too low the PCM will pull timing. If it's bad enough you will notice it (surging or like hitting a rev limiter).

As said above, if the LNF knocks on 93 (per HHRSSouth above), my guess is it will definitely surge or fall down with 87 if you are in any significant boost. When not in boost you probably won't notice anything.

I need to get my scanner out and see what mine is doing on this oxygenated E10 91 octane California gas. I had to pull a bit of timing from my GTO (on 91) and my 6.0L truck (on 87) because it would knock and pull enough timing you would lose some power. Backing them off keeps them out of the knock and the PCM doesn't pull timing. GM's knock routine is extremely aggressive. It pulls a lot of timing fast (attack) and returns it sllllooowwwlllyyyy (decay).

But for the $3.00 extra per full tank, I just run 91 and be done with it. Run top-tier gas too. We can't change the timing tables without GM knowing and I really like my warranty.

 

93 Octane Shell VPoewer since day one and nothing else

 

All I have personally used since owning is 93 ocatane also, I reset my ecm also after I ran the 1st tank from the dealer (didn't know what octane they stuck in it) and I put in 93 octane myself. I didn't want my computer thinking its suppose to run on 87 octane or 91 for that matter. I would not doubt that some dealers stuck 87 octane in our HHR SS because it was a cheaper fill up. Just something to think about for those of you getting a new HHR SS.

 

X2