Premium Fuel
Thread Starter
Instructor
Joined: Dec 2020
Posts: 213
Likes: 96
From: northville mi
Premium Fuel
This summer I expect to pay around 5.50 a gallon for 93 octane. I understand that regular fuel can be used since the knock sensors will automatically retard the timing. This only affects performance and drivability is still good from what i can tell. Any thought on this? Based on my average driving of 3000 miles annually. I calculate that I will pay an extra $255.00 this summer to drive my vette. Not that big a deal
Popular Reply
Mar 8, 2022, 12:26 PM
Pro
Joined: Apr 2021
Posts: 649
Likes: 803
From: DFW
The fact some folks are contemplating running their car in a sub-optimal manner to save a few bucks is mind boggling to me. On a $80k car, $255 is a rounding error.
Melting Slicks
Joined: May 2021
Posts: 2,562
Likes: 1,579
I won't run anything less than 93 in mine. The cost differential when compared to voided factory warranty seems insignificant. Everything on this vehicle is logged. I wouldn't be surprised if it will log the fact that bad gas was used too.
Moderator
Joined: Feb 2006
Posts: 38,952
Likes: 17,825
From: DFW Area TX
Is $255 worth potentially voiding your engine warranty? From the 2022 Owners Manual:
Recommended Fuel
Premium unleaded gasoline meeting ASTM
specification D4814 with a posted octane
rating (R+M)/2 of 91 or greater is required.
The use of the correct fuel is an important
part of the proper maintenance of the
vehicle and a condition of the vehicle
warranty. If heavy knocking is heard when
using gasoline rated at 91 or greater, the
engine needs service.
Do not use any fuel labeled E85 or FlexFuel.
Do not use gasoline with ethanol levels
greater than 15% by volume.
Premium unleaded gasoline meeting ASTM
specification D4814 with a posted octane
rating (R+M)/2 of 91 or greater is required.
The use of the correct fuel is an important
part of the proper maintenance of the
vehicle and a condition of the vehicle
warranty. If heavy knocking is heard when
using gasoline rated at 91 or greater, the
engine needs service.
Do not use any fuel labeled E85 or FlexFuel.
Do not use gasoline with ethanol levels
greater than 15% by volume.
Pro
Joined: Oct 2017
Posts: 517
Likes: 426
From: Myrtle Beach, SC
You bought this car fully knowing the fuel costs that came along with it. Be grateful it's as fuel efficient as it is given the power level. My old STI required premium and averaged 21 MPG despite having half the power of my C8. Ask a guy driving a Raptor or Ram SRT if he's putting regular in his truck.
Drifting
Joined: Apr 2012
Posts: 1,325
Likes: 465
This summer I expect to pay around 5.50 a gallon for 93 octane. I understand that regular fuel can be used since the knock sensors will automatically retard the timing. This only affects performance and drivability is still good from what i can tell. Any thought on this? Based on my average driving of 3000 miles annually. I calculate that I will pay an extra $255.00 this summer to drive my vette. Not that big a deal
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Le Mans Master
Joined: May 2005
Posts: 6,638
Likes: 279
From: Muscle Shoals, AL
Cruise-In VI Veteran
Cruise-In VII Veteran
In addition to the C8 using premium, my daily driver is a TRX that uses premium and gets 10-11 mpg if I drive easy.
Last edited by johnodrake; Mar 8, 2022 at 06:28 PM.
Race Director
Joined: Mar 2007
Posts: 11,234
Likes: 8,374
Do not use gasoline with ethanol levels
greater than 15% by volume."
Edited: I originally asked if this statement above from the Owner's Manjual was inconsistent, because I thought E85 meant 15% ethanol (it does not). I even looked it up before posting and the first site I found said exactly that - 15% - but it was wrong. E85 has a much higher percentage of ethanol - as noted by those who commented below on my original post - and quoted the DOE definition of E85.
Last edited by Andybump; Mar 9, 2022 at 06:41 AM. Reason: Fix my error
Race Director
Joined: Aug 2016
Posts: 12,706
Likes: 10,132
From: Garden Valley CA
"Do not use any fuel labeled E85 or FlexFuel.
Do not use gasoline with ethanol levels
greater than 15% by volume."
Is this statement a a bit inconsistent? It implies that you can use fuel with 15% ethanol, but says you cant use E85 which I thought meant exactly that - 15% ethanol. Anyway, I dont plan to use it - premium is available here and that is what I use.
Do not use gasoline with ethanol levels
greater than 15% by volume."
Is this statement a a bit inconsistent? It implies that you can use fuel with 15% ethanol, but says you cant use E85 which I thought meant exactly that - 15% ethanol. Anyway, I dont plan to use it - premium is available here and that is what I use.
Racer
Joined: Feb 2021
Posts: 296
Likes: 207
The way things are going I am assuming $10.00/ gallon for premium for my June drive Denver to Spring Mountain and back (including a little bit on route 66 East through Winslow, Albuquerque, etc), assuming 28 mpg highway (too optimistic?) comes to an extra $342, less than the cost of a single night at a hotel on the Vegas strip.
Was just talking with my friend about oil barrel prices. Obviously the dummies in the White House will figure out something because there would be an absolute riot if gas got any higher than it is now lol
I'm l sure that we're probably at the maximum within maybe 50 cents a gallon or so... Depending on area of course. If you live in California good luck!
Pro
Joined: Apr 2021
Posts: 649
Likes: 803
From: DFW
The fact some folks are contemplating running their car in a sub-optimal manner to save a few bucks is mind boggling to me. On a $80k car, $255 is a rounding error.
Race Director
Joined: Mar 2007
Posts: 11,234
Likes: 8,374
So between using 91 which is acceptable and higher octane that is recommended, what is affected by running 91? I assume that the engine adjusts timing to avoid the knock or ping - and I assume that this in turn reduces available horsepower. Is fuel mileage less? Does the engine produce a little more heat (note you wont see a higher coolant temperature necessarily since the cooling system has significant capacity to maintain the target temperature, but it could still have more heat to dissipate due to the slightly retarded timing). Anything else - more deposits or something? My wife's Suburban is approved for flex fuel - but when we have tried that, the fuel mileage is significantly less.
Advanced
Joined: Jun 2020
Posts: 81
Likes: 53
From: Rockford, IL
Back when I was young and we hopped up a motor we averaged 6-8 MPG and probably only made 300 HP. We used to joke that we could pass everything except a gas station. I marvel at the way my Z51 C8 gets 30 MPG on the highway, and has great HP. I would never put anything in that was not 93 if possible. My race cars used to use 106+ octane and only made 600 HP. That was not that long ago.
Race Director
Joined: Aug 2016
Posts: 12,706
Likes: 10,132
From: Garden Valley CA
So between using 91 which is acceptable and higher octane that is recommended, what is affected by running 91? I assume that the engine adjusts timing to avoid the knock or ping - and I assume that this in turn reduces available horsepower. Is fuel mileage less? Does the engine produce a little more heat (note you wont see a higher coolant temperature necessarily since the cooling system has significant capacity to maintain the target temperature, but it could still have more heat to dissipate due to the slightly retarded timing). Anything else - more deposits or something? My wife's Suburban is approved for flex fuel - but when we have tried that, the fuel mileage is significantly less.
It is also interesting that 2022 cars no longer reference 93 octane as the recommended fuel.