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2017 3LT Stingray
Buddy and I are thinking about taking a trip to out west in my Vette. Possibly 4,000+ miles. Normal driving, lots of interstate and no hot-rodding. I know the computer adjusts for varying octane, but is this long of a distance ok ?
 

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I seem to recall that while you can run on the 87 octane, you will find you actually get poorer gas milage. I would recommend you stick with the 91 and seek out Costco along your run. They are typically 20 to 40 cents cheaper per gallon on 91 octane vs a Shell or Texaco. Costco only sells Top Tier gas.
 

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Costco purchases "top tier" gasoline from the closest local refineries based on the best rate they can get. The additives in their fuel is determined by the additives that the select refinery uses in their fuel. I've never run 87. I've also never run anything but Chevron because I'm a fuel snob. Please share your results.
 

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When I picked up my car from the dealer I had full 91 to 93 Octane and a 250+ mile drive home. I put it in Econ, and made it all the way home on 1 tank, 75 to 80 MPH. Using cheap gas leads to expensive injector repair (‘87 Mustang GT), so I only use the good stuff.
 

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I seem to recall that while you can run on the 87 octane, you will find you actually get poorer gas milage. I would recommend you stick with the 91 and seek out Costco along your run. They are typically 20 to 40 cents cheaper per gallon on 91 octane vs a Shell or Texaco. Costco only sells Top Tier gas.
I have no problem mix 91 or 93 with 87 no brainer for me any way
 

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My sense is that 87 octane fuel is only to be used when premium is just not available and then only just far enough to get the car to premium fuel. Technically speaking, the risk of engine damage is real with low octane (87) from detonation. You will hear it as a soft knocking, especially when accelerating or when the engine is under load such as climbing a hill. An entire trip with 87 octane would most certainly cause engine damage. You don’t have to believe me, just read your owner’s manual on this subject, which reads in part:

“If equipped with the LT1 engine, use premium unleaded gasoline meeting ASTM specification D4814 with a posted octane rating of 91 or higher. Regular unleaded gasoline rated at 87 octane or higher can be used, but acceleration and fuel economy will be reduced, and an audible knocking noise may be heard. If this occurs, use a gasoline rated at 91 octane or higher as soon as possible. Otherwise, the engine could be damaged. If heavy knocking is heard when using gasoline with a 91 octane rating or higher, the engine needs service.”

Have a great trip!
 

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2017 3LT Stingray
Buddy and I are thinking about taking a trip to out west in my Vette. Possibly 4,000+ miles. Normal driving, lots of interstate and no hot-rodding. I know the computer adjusts for varying octane, but is this long of a distance ok ?
A couple years ago I got 33mpg on a 200 mile trip at interstate speeds on regular 87 gasoline in my 2016 2LT. The mpg was done using a pencil & paper. Here in Ohio the county auditors verify that you are getting an accurate volume of gasoline. But they don't check the octane numbers. So when you purchase 93 octane gasoline are you getting 93?? With newer cars most people would never know. Some drivers who know and use the potential performance of their cars may tell the difference in octane.
 

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Even if you only averaged 26.7 mpg over the course of 4000 miles you would use 150 gallons at a dollar per gallon more than 87 octane that’s $150 or one night of a hotel room. When you use a lower octane the knock sensors detect it and retard the timing giving you less performance and more importantly less gas mileage. You don’t hear the knock because the computer is doing everything to eliminate it.
 

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2017 3LT Stingray
Buddy and I are thinking about taking a trip to out west in my Vette. Possibly 4,000+ miles. Normal driving, lots of interstate and no hot-rodding. I know the computer adjusts for varying octane, but is this long of a distance ok ?
There was a change for 2017 and newer C7 and the owners manual states 93 octane is required. It states 87 can be used if nothing else is available. Given that you are driving 4k miles and is we assume 30 MPG you will use 133 gallons of fuel. If the 93 octane costs $.60 more per gallon you would only save $80 bucks on fuel. I would just spend the $80 and remove any doubt. Even splitting the difference and going to 91 which was OK up to 2017 would only cost you about $40 bucks.
 

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There was a change for 2017 and newer C7 and the owners manual states 93 octane is required. It states 87 can be used if nothing else is available. Given that you are driving 4k miles and is we assume 30 MPG you will use 133 gallons of fuel. If the 93 octane costs $.60 more per gallon you would only save $80 bucks on fuel. I would just spend the $80 and remove any doubt. Even splitting the difference and going to 91 which was OK up to 2017 would only cost you about $40 bucks.
 

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If 93 is required there are a lot C8 owners in California using 91. The engines adjust timing for lower octain fuel. Would I choose to solely run regular no - at a minimum I will mix mid grade with 91 - no problems no knocking. What do you do If there isn’t premium is available you use mid grade or regular….
 

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Note: The Owners Manuals beginning in 2017 said 93 Octane is highly recommended. It does not say it is required for the LT1 engines. A lot of owners have only used 91 octane without any issues for years.
 

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I guess I'm weird.... I run 93 PERIOD. I look at it this way; if a couple of bucks a tankful is going to break me or hurt my wallet then I shouldn't have bought the Vette in the first place...
 

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If 93 is required there are a lot C8 owners in California using 91. The engines adjust timing for lower octain fuel. Would I choose to solely run regular no - at a minimum I will mix mid grade with 91 - no problems no knocking. What do you do If there isn’t premium is available you use mid grade or regular….
The C8 owners manual for 2023 says 91 octane is reccommended. That was true for the C7 2014 to 2016. In 2017 Chevy changed the reccomendation for the C7 to be 93 octane.
 

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Just returned from a road trip from Buffalo, NY to Key West FL and back. Used 91 all the way. Base 2015 stingray, 7sp manual.
Speedometer Odometer Gauge Automotive design Vehicle

See attached image. Had occasion to hit 95 mph.
 

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Costco purchases "top tier" gasoline from the closest local refineries based on the best rate they can get. The additives in their fuel is determined by the additives that the select refinery uses in their fuel. I've never run 87. I've also never run anything but Chevron because I'm a fuel snob. Please share your results.
That's not correct. Costco has their own additive mix that is added to the fuel AT THE STATION, not at the terminal. And all Costo gas is Top Tier.
 
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The C8 owners manual for 2023 says 91 octane is reccommended. That was true for the C7 2014 to 2016. In 2017 Chevy changed the reccomendation for the C7 to be 93 octane.
For 2020 and '21, the OM said 93 was required, 91 could be used with a loss of performance. In 2022, they changed it to 91 required. No one outside of GM knows if there were actual changes to the engine / fuel system that allows the car to run better on '91, or if GM just got tired of owners in California complaining they couldn't get 93. The consensus on the internet (which MUST be true, right? ;)) is the second.

In either case, running 91 won't hurt your car, it will potentially cause the ECU to retard timing, which effects performance and mileage. I suspect only under heavy load or in high heat would you notice the difference. And at higher altitudes, octane requirements are reduced (which is why in high altitude areas 91 is generally the highest you can find.).

87 Octane? Under light load, in moderate to cold temps, it's doubtful you'll have any problems. I wouldn't run it in hot temps, or when I'm going to be running the car hard. In fact, I wouldn't run it at all unless it was all I could find when I really needed gas.

I agree with Yellow n Red, though. If you do the math, the difference in cost is pretty minor. If you can afford $40K, $60K, $80K, or $100K for a car, is it worth putting lower octane fuel in it to save a few bucks? If you average 15 mpg, and put 10,000 miles a year on your car (probably a lot more than most owners do), you're using 666 gallons of gas. If Premium costs 50 cents a gallon more, you're spending an extra $333 a year. If you only put 5000 miles a year on, only $116. If that's a hardship, you probably can't really afford a Corvette.
 
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