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
Drifting
Joined: Apr 2010
Posts: 1,479
Likes: 33
From: Jacksonville Florida
93 octane is easy to come by where I live in Florida and it is mostly what I put in the car. I did try a few tanks of Plus (89 octane) a couple of years ago to see if it would work OK. I don't drive the car really hard and I couldn't tell any real difference in performance for my daily driving. I did notice a drop in gas mileage for those 3 tanks and it seemed that the increased mileage on the 93 octane tanks pretty much paid for the increased cost of the Premium so I've stayed with the 93 octane since that test. Your results may vary!!
I will say that when I posted that I was experimenting with the 89 octane I got pretty slammed on the Forum. Most common comment was that if I couldn't afford the fuel that the car should have I should sell the car and buy (insert favorite crappy, cheap car here).
I will say that when I posted that I was experimenting with the 89 octane I got pretty slammed on the Forum. Most common comment was that if I couldn't afford the fuel that the car should have I should sell the car and buy (insert favorite crappy, cheap car here).
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 5,027
Likes: 833
From: Rotonda West, FL 2015 Z51 M7 3LT
Oldtimer
boy... a true test would be interesting. Zmeister; if people are that shallow.... just tune 'em out. If you can afford a Vette running 93 ain't gonna break you up... that's not the point or question.... sheesh... tell 'em to get a life.
Race Director
Joined: Jan 2008
Posts: 16,027
Likes: 170
From: oregon
you may be able to scoot by in the winter but in the heat of summer knock is hell on ringlands and bearings. using lower octane is a good way to save $1 on a fill up and risk a shorter life on much more expensive parts. knock sensors react to knock, they don't act ahead of it
Drifting
Joined: Mar 2011
Posts: 1,412
Likes: 15
From: Richardson TX
There are dozens of threads about this... and its in your user manual.
The car/engine is made for premium fuel, 91+ octane.
If you put something lower, the ECM will adjust the timings accordingly. However, running lower octane will cause some predetonation, and will put more wear on your engine, not to mention decrease your power.
So, no, its not catastrophic for your engine, but it is not advised.
The car/engine is made for premium fuel, 91+ octane.
If you put something lower, the ECM will adjust the timings accordingly. However, running lower octane will cause some predetonation, and will put more wear on your engine, not to mention decrease your power.
So, no, its not catastrophic for your engine, but it is not advised.
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 5,027
Likes: 833
From: Rotonda West, FL 2015 Z51 M7 3LT
Oldtimer
I know what it says - then there's usually reality. My 97 ran fine on 87 - never knocked once. If the search engine here worked I'd use it. To put it mildly - it sux So, now that we've got the pleasantries out of the way.
Thanks for your opinion.
Thanks for your opinion.
Race Director
Joined: Jan 2008
Posts: 16,027
Likes: 170
From: oregon
you can't hear knock especially in the car. that rattle you may be thinking of at 2500rpm isn't what cracks ringlands, detonation at 6000rpm that you can't hear because it's masked with engine noise is what normally takes stuff out
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 5,027
Likes: 833
From: Rotonda West, FL 2015 Z51 M7 3LT
Oldtimer
excellent point racebum, and one I hadn't considered. Just to set the playing field, I run 93 in my lawn mowers, snowblowers, weedwackers, generator, etc.... so I'm not adverse to spending the $. As has been said, it's not that big of a deal in the grand scheme of things. I was just curious of others views and opinions, and whys.
I've been on forums a long time and sometimes mid-winter - a good discussion thread is a pleasant diversion from the weather. Well... for those of us who actually get winter. ;-)
I've been on forums a long time and sometimes mid-winter - a good discussion thread is a pleasant diversion from the weather. Well... for those of us who actually get winter. ;-)
Melting Slicks
Joined: Mar 2004
Posts: 2,388
Likes: 405
From: Horseshoe Bend ID
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Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
Interesting results. It just goes to prove that the ones who say they use 87 are not as numerous as you'd think from the posts in the octane threads.
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
4th Gear
Joined: Dec 2012
Posts: 4
Likes: 0
I'll never run cheap again. I have not tried 87 with octane boost though.
Last edited by Tuggo; Jan 17, 2013 at 07:01 AM.
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 5,027
Likes: 833
From: Rotonda West, FL 2015 Z51 M7 3LT
Oldtimer
Pretty clear - when dealing with this kind of motor it makes sense to run the high octane. Not that many miles go on it anyhow so for one or two bucks a tank - just makes sense. Just ran through my mind so I thought I'd ask for opinions....
Got 'em... lol -
Got 'em... lol -
Drifting
Joined: Oct 2011
Posts: 1,872
Likes: 333
From: Olmsted Falls Ohio
St. Jude Donor '12 thru '24
I run Shell 93 mostly because of the detergent package, it conforms to the manufacturer's recommendation, and it's rated as Top Tier fuel. If I can't get Shell, I'll take any Top Tier fuel I can get. By the way one of the requirements of being rated as a Top Tier fuel is an ethanol content between 8 and 10%.
Melting Slicks
Joined: Mar 2006
Posts: 3,456
Likes: 102
From: Piedmont Va
St. Jude Donor '11-'12-'13,'19-'20
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 5,027
Likes: 833
From: Rotonda West, FL 2015 Z51 M7 3LT
Oldtimer
hmmm. that's good to know pickle - thanks. I have one Shell around here. I used to run Sunoco 94 in my motorcycles and '69 Dodge Charger but haven't seen that around in years.
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
I have stripped down many LS6s. those with light touch on the go peddle sure have gummed up heads.
Those of us who are 3000 to redline
WOT have nice and clean cylinder heads. 87 will work, as long as you dont stomp on the go peddle hard.
we run 93 in the 04 and I run a 4:1 mix of 93/100 in the 03 track car. both are 100% petrol, no EtoH added.
and fuel is fuel no matter what station it comes from. All come from the same distribution terminals.
If there are different distribution terminals then the fuel may be different.
Last edited by AU N EGL; Jan 17, 2013 at 03:06 PM.
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 5,027
Likes: 833
From: Rotonda West, FL 2015 Z51 M7 3LT
Oldtimer
so Au, it sounds like getting on them is the right thing to do. That wouldn't really surprise me a whole lot though, I suspect that's what they were designed for. I'm definitely going to run 93 as that's all we can get here.