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Not again - the bottom line is the Gen 1 Cruzes - all of them including the LS - included the KRD option code for "91 octane". This code was applied because the engine itself was tuned for 91 octane. The only reason you can run 87 octane in these cars is due to the knock sensors embedded in the engine and ECU programming that listens to those sensors and automatically detunes the engine for 87 octane. There are two ignition maps in the car as a result. The real world result in the Gen 1 Cruze was a loss of up to 10% of your power and fuel economy. Take a look at https://www.edmunds.com/chevrolet/c...ot-weather-mpg-test---regular-vs-premium.html for a real world comparison of 87 vs. 91 octane in the Gen 1 Cruze LTZ.
 

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Yeah, where I live it is not worth the 40 cent/gallon more for high test, even if it nets you a little mileage increase. I've never gotten worse than 30 mpg since buying my 13' LTZ new in fall of 2012. Tried running high test a couple of tanks, seemed to have a little more power, but not enough to warrant the cost difference. Been using 87 since new, and never had any issues. Winter gas nets me around 30-31 mpg, summer gas around 34-36 mpg. Got 85k miles on her and still going strong. To say it delivers premium benefits to my car is fiction, 87 and 91 both have the same detergents in them and cleaning abilities. To say it will net better fuel mileage in a car that is tuned to run on higher octane is fact. Waste of money to me, but to each their own though.
 

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Never noticed any power difference running anything more than 87 in 2011 cruze LS 1.8L. My son still owns the car, it's got 150k miles now. All run on 87 octane. Motor is a slug but a very consistent slug, and the gearbox is evenly spaced and dreamy, very very nice.

The idea of trying to get more power or torque out of such a sluggish motor by putting premium fuel is laughable to me, total waste of money. I recommend everyone run the lowest possible supported octane in any gas powered vehicle unless glaring performance/mpg difference is observable.

When premium is "recommended" for your car that translates to this: 87 octane is supported, so DO NOT WASTE YOUR $ on premium unless its summertime hot, in which case you will likely notice change in power&torque and maybe mpg.

I'll see all you gasser cruze people in the rearview mirror of my cruze diesel whether you put 87 or 91 in your gasser cruze; just accept that compared to diesel cruze drivers, gas cruze drivers are gas-guzzling slowpoke whale-killers at any octane.
 

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Never noticed any power difference running anything more than 87 in 2011 cruze LS 1.8L. My son still owns the car, it's got 150k miles now. All run on 87 octane. Motor is a slug but a very consistent slug, and the gearbox is evenly spaced and dreamy, very very nice.

The idea of trying to get more power or torque out of such a sluggish motor by putting premium fuel is laughable to me, total waste of money. I recommend everyone run the lowest possible supported octane in any gas powered vehicle unless glaring performance/mpg difference is observable.

When premium is "recommended" for your car that translates to this: 87 octane is supported, so DO NOT WASTE YOUR $ on premium unless its summertime hot, in which case you will likely notice change in power&torque and maybe mpg.

I'll see all you gasser cruze people in the rearview mirror of my cruze diesel whether you put 87 or 91 in your gasser cruze; just accept that compared to diesel cruze drivers, gas cruze drivers are gas-guzzling slowpoke whale-killers at any octane.
Actually if youd bothered to do any research, you'd realize that midgrade or premium DOES make a difference for the 1.4t which has an octane map to take advantage of it, and that the diesel is not any quicker in any instrumented tests than a 1.4T, new gen or old. It has more torque at partial throttle, and is programmed to do so, but foot to the floor, they're on equal ground. 1.8 - yah, it's a gutless wonder.

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Yeah, where I live it is not worth the 40 cent/gallon more for high test, even if it nets you a little mileage increase. I've never gotten worse than 30 mpg since buying my 13' LTZ new in fall of 2012. Tried running high test a couple of tanks, seemed to have a little more power, but not enough to warrant the cost difference. Been using 87 since new, and never had any issues. Winter gas nets me around 30-31 mpg, summer gas around 34-36 mpg. Got 85k miles on her and still going strong. To say it delivers premium benefits to my car is fiction, 87 and 91 both have the same detergents in them and cleaning abilities. To say it will net better fuel mileage in a car that is tuned to run on higher octane is fact. Waste of money to me, but to each their own though.
The question always comes down to the following:

  • Do you as the driver notice a difference with higher octane?
  • Is any noticeable difference worth it to you for the increased cost at the pump?

The answer to both of the above must be yes or you are simply wasting your money when using higher octane. In the case of my 2012 ECO MT when I ran 87 octane it felt like the clutch was slipping. In addition the car just didn't respond in the thinner, hot summer air at 6,000 ft. I was more than willing pay the premium price to get a better performing car. Many of our members have reported 89 octane is their happy place when it comes to price/performance.

I suspect the same questions are applicable to the Gen 2 Cruze.
 

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Never noticed any power difference running anything more than 87 in 2011 cruze LS 1.8L. My son still owns the car, it's got 150k miles now. All run on 87 octane. Motor is a slug but a very consistent slug, and the gearbox is evenly spaced and dreamy, very very nice.

The idea of trying to get more power or torque out of such a sluggish motor by putting premium fuel is laughable to me, total waste of money. I recommend everyone run the lowest possible supported octane in any gas powered vehicle unless glaring performance/mpg difference is observable.

When premium is "recommended" for your car that translates to this: 87 octane is supported, so DO NOT WASTE YOUR $ on premium unless its summertime hot, in which case you will likely notice change in power&torque and maybe mpg.

I'll see all you gasser cruze people in the rearview mirror of my cruze diesel whether you put 87 or 91 in your gasser cruze; just accept that compared to diesel cruze drivers, gas cruze drivers are gas-guzzling slowpoke whale-killers at any octane.
I ran an experiment on my son's 2012 LS MT while he was in college. His LS definitely performed better, not by much mind you, but better on 91 octane. It also returned slightly better MPG. However, I'm not sure it was enough to warrant spending the extra at the pump.
 

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I"m not seeing ANY difference between 85 and 91.

Test again in summer.

My aunt and uncle run 85. They started with 91. They've got higher compression ratios then us. They didn't see any difference either. They've got over 40k miles on both their vehicles.
 

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I recommend a very simple test: Run a couple of tanks of regular 87, calculate the MPG, then run a couple of tanks of higher octane, calculate the MPG. Drive consistently in city/hwy for this test. Then look at MPG, compare. When I did this test in my 1996 Saturn I was amazed to find the 92 Octane delivered about a 10% MPG improvement, about 33 to 37 MPG. The cost of the higher octane fuel where I'm located is about 10% more.. so I'm not wasting or saving money to use the higher octane fuel in that car, so I DO use it, because the car does have noticeably more power (and really, really needs all the help it can get!).. and it ends not costing any more overall making it an easy choice.

Results may vary, but I would expect an even bigger gain for a turbo charged engine like the 1.4L.
 
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I get better mileage from ethanol free. Not from increased octane.

Every owners manual i've had the luxory of reading in my cars. Have always said 87 octane. Even my motorcycles say 87.

It's an industry standard. With 87 as the number. Been that way LONG before leaded gasoline was discontinued.
 

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If I don't put 93 in my Cobalt, there's going to be a problem...of the rod-leaving-block or hole/crack-in-piston variety.

Plenty of cars call for higher octane. All the 5.7L Hemis call for 89, of all things.

Leaded gas was far more than 87 octane - lead raises the octane value a whole **** of a lot. When you're talking 12:1 or 13:1 compression ratio on an engine with iron heads, you need a huge octane value to avoid detonation.
 
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