View Poll Results: Which octane do you run in your '03 base coupe or vert?
Voters: 107. You may not vote on this poll
Fuel octane level
Thread Starter
Le Mans Master
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From: Rotonda West, FL 2015 Z51 M7 3LT
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Fuel octane level
******** The poll says "03 but disregard that and translate it to C5. It won't et me change the poll options. Sorry! ****************
ok - next pita question... Figured I'd try this one out as a poll...
In my '84 and '97 I ran 87 octane in both with no seemingly detrimental effects. I don't race 'em though. If the guy beside me is faster, I really could not care less.
So this soon-to-be-mine '03 seems to "want" 93. But for just drivers out there, not the racers, which to you run?
ok - next pita question... Figured I'd try this one out as a poll...
In my '84 and '97 I ran 87 octane in both with no seemingly detrimental effects. I don't race 'em though. If the guy beside me is faster, I really could not care less.
So this soon-to-be-mine '03 seems to "want" 93. But for just drivers out there, not the racers, which to you run?
Last edited by calvins; Jan 16, 2013 at 09:54 AM.
Thread Starter
Le Mans Master
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From: Rotonda West, FL 2015 Z51 M7 3LT
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I run 91 octane in mine as that is the highest available here. The owner's manual recommends premium but says you can run lower octane with reduced perfomance the result. From the '03 owner's manual:
Here, premium is about 20 cents higher per gallon than regular or mid-grade. For that little difference, I'll keep on putting premium in and not worry about the effects of a lower octane gas.
Gasoline Octane
Use premium unleaded gasoline with a posted octane of 91 or higher for best performance. You may also use middle grade or regular unleaded gasoline rated at 87 octane or higher, but your vehicle’s acceleration may be slightly reduced. If the octane is less than 87, you
may get a heavy knocking noise when you drive. If this occurs, use a gasoline rated at 87 octane or higher as soon as possible. Otherwise, you might damage your engine.
Use premium unleaded gasoline with a posted octane of 91 or higher for best performance. You may also use middle grade or regular unleaded gasoline rated at 87 octane or higher, but your vehicle’s acceleration may be slightly reduced. If the octane is less than 87, you
may get a heavy knocking noise when you drive. If this occurs, use a gasoline rated at 87 octane or higher as soon as possible. Otherwise, you might damage your engine.
Thread Starter
Le Mans Master
Joined: Jun 2002
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From: Rotonda West, FL 2015 Z51 M7 3LT
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From: Central PA. - - My AR15 identifies as a muzzleloader
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I'd say there's some pretty serious slant to the results of this poll. Using regular is a minority thing.
Truth is, there's no reason for 93 to cost .01 more than 87, it's all bs anyway.
Truth is, there's no reason for 93 to cost .01 more than 87, it's all bs anyway.
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From: Iowa
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The vast majority of gas stations around here don't have 93, just 91. That being said, I go out of my way to get 93 for my 98 C5 and use either 91 or 93 for my 02 C5.
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We have both 91 and 93 depending on station. All are E10. I try and go for Sonoco or Shell 93 in both my vettes. I am a firm believer that better gas makes for more efficient combustion...the higher the compression the more gain from improved efficiency. While C5 ECM's will adapt to lesser grades, you will be sure to lose power and fuel mileage, and probably need to run more techron, seafoam etc over the years to keep things clean out. That being said, gas is gas when it leaves the refinery. Depending on transport methods, transporter etc it's hard to tell what ends up in the tank under a specific pump. Most name retailers test and doctor the fuels at their local terminals and transport to reatil under strict corporate guidelines. You are more likely to get what it says on the pump from Exxon, Shell, Sonoco etc. Independents and Discounters on the other hand buy from whatever wholesaler is cheaper on any given day. In my opinion it's a crap shoot on what you get when you buy from them. 87 from Shell might be better gas than 91 from Sheetz. Only took one tank of bad gas to break me of the habit. Lots of folks will disagree..
Flame away boyz! 
Flame away boyz!
