Ethanol free 93 Octane vs E10 93 Octane
Thread Starter
Burning Brakes
Joined: Jun 2022
Posts: 752
Likes: 255
From: Florida
Ethanol free 93 Octane vs E10 93 Octane
Since getting my 13 base a year ago with just under 30k miles I've just used whatever top tier 93 was convenient. Recently my local station ran out of 93 and was selling 93 Ethanol free for the same price so I filled the tank. About 200 miles later I noticed a slightly smoother idle and an impressive 1.5 to 2 MPG increase. Went back the regular 93 and again within a few hundred miles the fuel economy dropped back.
Am I imagining this or is it possible this is better for the car. Price isn't horrible at 30 cent more.
Am I imagining this or is it possible this is better for the car. Price isn't horrible at 30 cent more.
Pro
Joined: Apr 2016
Posts: 603
Likes: 245
From: Indiana
Since getting my 13 base a year ago with just under 30k miles I've just used whatever top tier 93 was convenient. Recently my local station ran out of 93 and was selling 93 Ethanol free for the same price so I filled the tank. About 200 miles later I noticed a slightly smoother idle and an impressive 1.5 to 2 MPG increase. Went back the regular 93 and again within a few hundred miles the fuel economy dropped back.
Am I imagining this or is it possible this is better for the car. Price isn't horrible at 30 cent more.
Am I imagining this or is it possible this is better for the car. Price isn't horrible at 30 cent more.
6th Gear
Joined: Oct 2025
Posts: 6
Likes: 0
Using ethanol in C6 Corvette.
I do believe the vehicle manual specifically states do not use ethanol! FYI, I then asked a physical chemist why and the short answer is it's a high performance engine with very tight specifications and ethanol will damage the engine.
Thread Starter
Burning Brakes
Joined: Jun 2022
Posts: 752
Likes: 255
From: Florida
I know for 100% fact that even E85 is safe if the car is tuned for it.
Safety Car
Joined: May 2016
Posts: 4,669
Likes: 1,849
From: Erlanger, Kentucky
Since getting my 13 base a year ago with just under 30k miles I've just used whatever top tier 93 was convenient. Recently my local station ran out of 93 and was selling 93 Ethanol free for the same price so I filled the tank. About 200 miles later I noticed a slightly smoother idle and an impressive 1.5 to 2 MPG increase. Went back the regular 93 and again within a few hundred miles the fuel economy dropped back.
Am I imagining this or is it possible this is better for the car. Price isn't horrible at 30 cent more.
Am I imagining this or is it possible this is better for the car. Price isn't horrible at 30 cent more.
If there was a gas station near me that had ethanol-free 93, that's what I'd be using in all my vehicles.
Racer
Joined: Jul 2015
Posts: 312
Likes: 38
The Corvette is 50 state compliant. There should be zero issues running ethanol as all states have oxygenated fuel. Ethanol is hard on plastic and rubber not made to be ethanol old resistant. All modern vehicles can safely use ethanol blended fuels.
Burning Brakes
Joined: Jun 2021
Posts: 801
Likes: 408
From: NC
Ethanol fuels have a 6 month life versus 1 year for non-ethanol. Since my 2 collector cars are not driven regularly, especially during the winter months, I use 93 octane ethanol free. Both Shell and Mobil have it in my town. Tends to be about 20 cents more, but who cares.
Pro
Joined: Oct 2024
Posts: 728
Likes: 399
From: WI
As someone else stated, the reason for the MPG increase is because gasoline has a higher energy density than ethanol.
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