# 87 vs 91 octane



## TGreyCruze (Feb 21, 2011)

Well recently i did this test were i wanted to run 87 initially and i was only getting 21.5-21.7 mpg. I know, i know its low for city driving but my wife's driving isnt the best with the jack rabbit starts and not letting off the gas a little when the rpm's start going up. Either way now im using 91 octane and now were getting 22.8-23.1 mpg. I do want to state that even with 87 octane if i just drive and not my wife i can pull easily 24.5-25 MPG's so im sure i can do higher then that with 91 octane if i just drive, since i use the tap shift and shift at very low rpm's. Im not really shocked at all since i would expect the higher octane to give me a little better gas mileage but i wanted to see how much better.

I honestly didnt feel like i got any performance out of it going with a higher octane just did it for the MPG's. Im thinking once i get the Trifecta tune with the Eco mode and the 91 octane combo this will make a bigger difference and in the end pay off and then some. This isnt done by a professional and by no means am i qualified in anyway to test and give facts on what works and doesnt. Just from my own experience by filling up the tank and reseting the MPG's. Im sure there is a better way of doing it ofcourse.


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## montgom626 (Jan 16, 2011)

TGreyCruze said:


> I know, i know its low for city driving but my wife's driving isnt the best with the jack rabbit starts and not letting off the gas a little when the rpm's start going up.


U think? Hammer that throttle baby!


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## Big Tom (Mar 8, 2011)

The problem I see with higher octane fuel now is with the very high price of gas, people who should use the 91-93 are using 89 to save money. Also less people are driving high perf cars as much which makes the good gas sit at the station in the tanks longer. In my motorcycle I can tell when I get old gas right away. Make sure you look for a high volume station when you purchase your gas to make sure you getting what you paid for. I also try to choose a pump that just had a motorcycle or Corvette sitting at it to have a better chance to get a full hose of the good stuff.


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## shawn672 (Oct 31, 2010)

Its a 20 cent difference between 87 and 91... That's about $2.25 per fill up... I don't think anyone should be concerned with the price of higher octane. I spend more money on soda everyday than I do on the premium gas for that day


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## Big Tom (Mar 8, 2011)

I'm sure none of us here on the forum do but there are lots of "other" people out there. I have seen some cheap people from time to time.


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## LJG (Jun 8, 2011)

You guys in the States are lucky with your fuel prices. We've just come back from a month’s road trip from Memphis down to Savannah on the East Coast, then up to Maine and across to Detroit and it was noticeably cheaper in comparison to Australia. It was dearer up north than down south, but not by much, I think it was $3.78 or thereabout down south and about $3.87 up north. 

Over here the base unleaded this morning in Brisbane was $4.99 a U.S. gallon equivalent, the top rating Premium Unleaded was $5.67 a U.S. gallon equivalent. For those with petrol models that makes quite a significant jump in price to go to the premium fuel, which the 1.4 ECO is supposed to run on I think. Diesel here this morning was $5.52 a U.S. gallon equivalent.

One thing that did give us a good laugh down south was the kangaroo Express service stations! I didn't have the heart to ask why they were called that, maybe because it makes your car hop further haha :jump: 


Kangaroo Fuel by LJG_Images, on Flickr


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## Aeroscout977 (Nov 25, 2010)

On our civics we found that the money saved from 87 vs >91 octane(required) per fill up actually cost the user more over the span of 6 months and longer due to MPG lost. I can't speak for numbers in the opposite category i.e. 87 required and switching to 91+ on OEM ignition timing. Just food for thought.


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## jakkaroo (Feb 12, 2011)

i peaked 39mpg with 89 got about 37-38 with 87 and thats 65


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## SilverIce2012 (Aug 9, 2012)

my 2012 Cruze has had a bit of hesitation lately. Wonder if it's the cold/12-inches of snow effecting the smooth drive? Any thoughts?


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## obermd (Mar 3, 2012)

SilverIce2012 said:


> my 2012 Cruze has had a bit of hesitation lately. Wonder if it's the cold/12-inches of snow effecting the smooth drive? Any thoughts?


12 inches of snow will give any low slung car fits. Cold weather will also make the car "stiffer" and less responsive until it completely warms up.


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