View Poll Results: Gas grade used for C4 Vette
87
4
17.39%
89
0
0%
91
19
82.61%
Voters: 23. You may not vote on this poll
Gas grade to use
Team Owner
Joined: Sep 2001
Posts: 62,143
Likes: 1,729
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Not one answer here, the C4 varies some in Compression Ratio during the long run.
My 86 ran perfectly on 87 octane. My 88 preferred midgrade when stock. Later cars could run midgrade or premium. So what year do you have?
The correct answer is hook up the scanner and run the lowest octane that doesn't give you any knock counts.
My 86 ran perfectly on 87 octane. My 88 preferred midgrade when stock. Later cars could run midgrade or premium. So what year do you have?
The correct answer is hook up the scanner and run the lowest octane that doesn't give you any knock counts.
Team Owner
Joined: Sep 2001
Posts: 62,143
Likes: 1,729
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Drifting
Joined: Mar 2003
Posts: 1,827
Likes: 212
From: Charlestown IN
Cruise-In V Veteran
I have an '85. I use 91 octane in everything I own. Including mowers. Gordon K told me these cars were designed to run on 87. No need for high octane gas. However, the gas we get here is garbage, The 91 does better. I work on small engines and I've seen the damage 87 can do.
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Safety Car
Joined: Mar 2003
Posts: 3,583
Likes: 504
From: Indianapolis IN
Finalist 2020 C4 of the Year - Unmodified
C4 of Year Finalist (stock) 2019
1986 iron heads running 87 octane with NO issues....I ran 87 in my aluminum headed 87 with the same results. Both ran/run just fine.
I refuse to waste money on higher octane fuel that will do nothing to improve the performance of my car that I could ever notice.
I refuse to waste money on higher octane fuel that will do nothing to improve the performance of my car that I could ever notice.
Burning Brakes
Joined: Oct 2017
Posts: 823
Likes: 106
From: Somewhere near Fort Wayne, Indiana
I run 87 in my 89, but I get a lot of shake under heavy throttle. I never considered it might be the octane, so I'll try some midgrade next tank. (It does say "Premium recommended" under the gas filler cover)
