Octane
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7th Gear
Joined: Oct 2019
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Octane
Hey I have an 87’ corvette and I’ve been putting 93 octane in it for the most part and 91 and 89 sometimes. What is the best to put in for this certain engine and year so it runs the best? Thanks
Le Mans Master
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From: Akron Ohio
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St. Jude Donor '09-'10-'11
That's just it, the knock sensor will allow the ecu to adjust timing based on knock. It will keep your engine safe regardless of what octane you use. Back when my car was a stock street car I ran 87 in it all the time until race day I would switch to 93.
Team Owner
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From: Athens AL
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My 86 ran all day on 87 octane and never knocked, my 88 got midgrade before I changed the engine. You want the lowest octane that doesnt knock for best performance.
The only way to truly know is hook a scanner up and see if you get knock counts while youre driving. Your compression is low enough that midgrade should be fine, but try not to use 87 octane.
The only way to truly know is hook a scanner up and see if you get knock counts while youre driving. Your compression is low enough that midgrade should be fine, but try not to use 87 octane.
Team Owner
Joined: Sep 2003
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From: Freedom is never more than one generation away from extinction.
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My 86 ran all day on 87 octane and never knocked, my 88 got midgrade before I changed the engine. You want the lowest octane that doesnt knock for best performance. The only way to truly know is hook a scanner up and see if you get knock counts while youre driving. Your compression is low enough that midgrade should be fine, but try not to use 87 octane.
My 86 also ran just fine on 87 to the day I sold her. I tried different octane fuels with zero performance or mileage results.
After following this topic for better than a decade, it's easy to say, running hi octane fuel (premium) does nada for low compression engines.
Safety Car
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From: Glenbeulah Wi
My 1986 vette would knock and pull timing even with 93 octane fuel when it was all stock. If I ran 87 octane fuel it could not pull enough timing to prevent it for detonating and you could hear it knocking. With 93 I could not hear it but the scanner showed lots of knock retard. The 9.5 compression, cast iron heads, and high operating temperatures of my car combined together to make 93 octane the best fuel fo me.
