Questions about using 100 plus octane fuel
Team Owner
Joined: Feb 2001
Posts: 27,254
Likes: 136
From: Short Hills, NJ
It could yes, if they were to ever test for it.
Not too much actually, the car might run the same as it would with 93 octane but in most cases could run notably worse. Without tuning for it (and even in some cases where you have tuned for it) 100 octane fuel can have a similar effect as using 87 octane fuel would, the car just won't run as well. On a stock/nearly stock C6 a fuel with a higher octane rating than 91-94 is simply not needed.
I wouldn't use it EVER, in a stock Corvette at least.
Not too much actually, the car might run the same as it would with 93 octane but in most cases could run notably worse. Without tuning for it (and even in some cases where you have tuned for it) 100 octane fuel can have a similar effect as using 87 octane fuel would, the car just won't run as well. On a stock/nearly stock C6 a fuel with a higher octane rating than 91-94 is simply not needed.
I wouldn't use it EVER, in a stock Corvette at least.
Safety Car
Joined: Jun 2004
Posts: 3,563
Likes: 2
From: Dallas Tx
If it's unleaded it won't cause any problems except for the large waste of money. Racing engines need racing gas. No street car needs racing gas unless built up with massive compression or boost. Then it's kind of getting away from a street car.
Or if your area can't get decent 92 or 93, then it would benefit a Vette or anything requiring premium to mix in a percent of 100 unleaded to boost up the octane to a decent level. If I could only get 91, I'd try a 1/4 tank of 100 mixed in.
Or if your area can't get decent 92 or 93, then it would benefit a Vette or anything requiring premium to mix in a percent of 100 unleaded to boost up the octane to a decent level. If I could only get 91, I'd try a 1/4 tank of 100 mixed in.
Last edited by Michrider; Aug 27, 2008 at 09:44 AM.
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Intermediate
Joined: Feb 2007
Posts: 42
Likes: 0
From: Morehead City N.C.
Octane & Horsepower
There's a really great post on the C-5 site (which I can't find right now) which talks about the relationship between octane ratings and actual engine output. Most of us grew-up thinking that the higher the octane...the more powerful the fuel...higher octane would result in better performance. Actually, that's not necessarily true. To be honest, a fuel rated in the 80's is probably more "explosive" than fuel rated at 100+. The reason is...that the higher octane ratings were a result of engines that had higher compression ratios. High octane was introduced as a way to solve the problem of detonation in high compression engines. So, the lower the octane rating...the higher the explosive capacity of a gallon of gasoline. I know it sounds counter to what we think...but the higher octane ratings are designed to counter "knock" and other problems that can destroy a high compression engine.
Safety Car
Joined: Feb 2007
Posts: 4,939
Likes: 448
From: CHOCOWINITY NC
There's a really great post on the C-5 site (which I can't find right now) which talks about the relationship between octane ratings and actual engine output. Most of us grew-up thinking that the higher the octane...the more powerful the fuel...higher octane would result in better performance. Actually, that's not necessarily true. .
Burning Brakes
Joined: Jul 2008
Posts: 923
Likes: 37
From: Green Bay Wisconsin
Team Owner
Joined: Aug 2006
Posts: 133,592
Likes: 30
St. Jude Donor '11, '16
I go with the manual too, 87.......The ECU curves will top out at no more than 93, without that information, the engines will never 'see' 100 octane.....And as others have posted, it may not burn in a similar fashion to 91, making it tough on the rest of the systems.....
Le Mans Master
Joined: Jan 2005
Posts: 5,611
Likes: 5
From: Thousand Oaks California
If you use a lower octane fuel that produces some detonation, the knock sensors will back out spark timing and therefore the fuel economy may decrease. This decrease in fuel economy is not because of lower gasoline energy content.
The C6 is designed to take advantage for gasolines up to 93 (R+M)/2 octane. A 93 octane gasoline will allow for maximun spark timing, thus providing the most available power and fuel economy. Beyond 93 R+M/2 octane gasoline, there is no advantage, since the electronic spark control programing will not provide additional spark timing, and also, since the compression ratio is fixed, there is no need or benefit for a fuel above 93 octane.
Last edited by calemasters; Aug 30, 2008 at 10:59 PM.
Team Owner
Joined: Feb 2000
Posts: 53,529
Likes: 77
From: Arizona
Possibly because 91 is the highest found in some areas. The web site has always said 93 for 'maximum performance', and I have mixed up my own 93 for years. But this past year with pump 91 I see or feel no difference. I don't race, and have not measured any parameters to see if there actually is any difference.
