regular grade vs. premium??
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Originally Posted by CFI-EFI
Regular gasoline, inherently, has more power than premium.
I don't know where that myth started...
http://www.vermontfuel.com/server/energy_specs.html
http://www.chevron.com/products/prod...h_Rvw_chp1.pdf
http://www.peterverdonedesigns.com/fuelandoctane.htm
Le Mans Master
Joined: Jul 2002
Posts: 5,818
Likes: 2
From: Alive and well in Burlington NC
When the fuel prices began to get near the $3.00 a gallon point (yeah, I know - which time) I decided to try a tank of 89 octane in my 1991 to see if there would be any noticeable differences. Granted, I did not have my laptop plugged up nor did I run a performance tuning program during this test. However, I do posses a highly sensitive and finely tuned Butt-o-meter. Within 15 miles of hyw driving I began to notice a marked lack of throttle response along with a change in exhaust tone (yes, the audio input is wet-wired to the butt-o-meter). The Vette also seemed to develop a slight off throttle hesitation in around town driving that as not present during the use of 93 octane fuel and seemed to require more of the right foot to negotiate some minor hills encountered during it's DD duties.
Overall the Vette felt and acted "sluggish".
It took almost a week to burn through the tank of 89 octane after which I have run through almost two tanks of 93 and all of the above noted symptoms have since disappeared.
Coincidence? Maybe, but I'll stick with the premium. It is Butt-o-meter approved
.
My $0.02
Overall the Vette felt and acted "sluggish".
It took almost a week to burn through the tank of 89 octane after which I have run through almost two tanks of 93 and all of the above noted symptoms have since disappeared.
Coincidence? Maybe, but I'll stick with the premium. It is Butt-o-meter approved
.My $0.02
Team Owner
Joined: Oct 2000
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From: Fort Knox, KY
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Originally Posted by WEH 2000C5
I burn 87 in my LT1 & have no problems. I'm a Senior Citizen & drive like one . My car has 157,000 mi. & I imagine the wear lowers the BMEP's a bit. Plus I'm hard of hearing from Piloting Jets for 33,000 hours & can't hear the pinging if my Hearing Aid Batteries aren't fresh.
Being old has the advantage of blocking out all the things that annoy younger people.
Being old has the advantage of blocking out all the things that annoy younger people.
Safety Car
Joined: Feb 1999
Posts: 3,504
Likes: 4
From: Mexico Beach FL
Originally Posted by Tom Piper
Here is a direct quote from my original '92 owner's manual:
"Be sure the posted octane for premium is at least 91 (at least 89 for middle grade and 87 for regular). If the octane is less than 87, you may get a heavy knocking noise when you drive. If it's bad enough, it can damage your engine."
Tom Piper
"Be sure the posted octane for premium is at least 91 (at least 89 for middle grade and 87 for regular). If the octane is less than 87, you may get a heavy knocking noise when you drive. If it's bad enough, it can damage your engine."
Tom Piper
Of course, there was not as much power because the ECM was retarding the timing to keep detonation from happening. That is why the text under my fuel door states that premium is recommended. It is recommended because most Corvette owners, especially when these cars were built, were more interested in perfomance, not cheap fuel.
I know a '93 owner that ran nothing but 87 octane for years with no problems.
Everyone has to decide what they want to run, but the bottom line is you won't hurt a '92 LT1 that is stock, like mine was, by running 87 octane in it.
Tom Piper
Team Owner
Joined: May 2002
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Originally Posted by Hot Rod 90
here's the breakdown i would generally go with:
'84-85: 87 octane
86-89: 87, or 89 octane max
90/91: 89, or 91 octane max
92-96 LT1: 91 or 92 octane
'84-85: 87 octane
86-89: 87, or 89 octane max
90/91: 89, or 91 octane max
92-96 LT1: 91 or 92 octane
That's a good start. I like the "maximums" on there too.
I would add that cars used mainly in higher elevations can go down a point or two safely. This fits in CFI's 85 octane. Although there are places in the midwest that sell 85 or 85.5 that aren't high elevation.Does anyone know the reasoning behind this reduced octane requirement?
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Melting Slicks
Joined: Mar 2003
Posts: 2,898
Likes: 0
From: Oklahoma City Oklahoma
Originally Posted by 91redragtop
With gas prices going to thru the roof for no reason, my question to everyone is this. Do I have to run premium gas in the 91 like the owners manual and the little stickers say, or can I run regular grade gas in it? It gets much better mileage than either one of our trucks but I can't justify spending the extra 20 cents a gallon. To me that just cancels out the better mileage. I need to know if we can run the regular grade, because right now, the vert is just a conversation piece sitting in the basement looking pretty.
I use 89 octane mid-grade in mine, and it works just fine. I've run regular in it before, but there is just the slight hint of a knock when you put your foot in it. With mid grade, I can't tell a difference between that and premium.
Sorry about the pic quality...just ran out and took it with my phone.
Safety Car
Joined: Sep 2002
Posts: 4,971
Likes: 9
From: The reason time exists is so everything doesn't happen at once
Originally Posted by Fuzzy Dice
Interestingly, below both phrases it is printed in French?...are they all like that or do I just have a Canadian honker?...
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by CentralCoaster
I don't know where that myth started...
It isn't a matter of having more, it is a matter of using what you have to greater advantage.
RACE ON!!!
Le Mans Master
Joined: Sep 2002
Posts: 8,991
Likes: 2
From: Hanger 18 Taxachusetts
Irregardless of the cost per gallon it is as you originally said, you don't want to pay the extra 10 cents a gallon difference. A 10 gallon fillup is going to cost you an extra buck ! Put the recommended good stuff in.
Sure at $3.00 gallon it costs $30, but at $3.10 it is only $31. No brainer !!
The sucky part is paying the base price in the first place.
Do what I did. Invest in VLO. They are an oil refinery company. Their stock has gone up over 20% in the past couple weeks !!! So let them raise the price. I am making more off the stock than it is costing me in gas !!!
Sure at $3.00 gallon it costs $30, but at $3.10 it is only $31. No brainer !!
The sucky part is paying the base price in the first place.
Do what I did. Invest in VLO. They are an oil refinery company. Their stock has gone up over 20% in the past couple weeks !!! So let them raise the price. I am making more off the stock than it is costing me in gas !!!
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by Steel Blue 91
Within 15 miles of hyw driving I began to notice a marked lack of throttle response along with a change in exhaust tone (yes, the audio input is wet-wired to the butt-o-meter). The Vette also seemed to develop a slight off throttle hesitation in around town driving that as not present during the use of 93 octane fuel and seemed to require more of the right foot to negotiate some minor hills encountered during it's DD duties.
Coincidence? Maybe, but I'll stick with the premium. It is Butt-o-meter approved.
My $0.02
Coincidence? Maybe, but I'll stick with the premium. It is Butt-o-meter approved
.My $0.02
RACE ON!!!
Last edited by CFI-EFI; Apr 20, 2006 at 02:20 PM.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by CentralCoaster
This fits in CFI's 85 octane. Although there are places in the midwest that sell 85 or 85.5 that aren't high elevation.
Does anyone know the reasoning behind this reduced octane requirement?
Does anyone know the reasoning behind this reduced octane requirement?
I can only speculate that the relatively high altitude and the lack of hills, allow the use of lower octane in some of the plain states.
RACE ON!!!
Burning Brakes
Joined: Feb 1999
Posts: 1,157
Likes: 3
From: Encino CA
Originally Posted by 91redragtop
With gas prices going to thru the roof for no reason, my question to everyone is this. Do I have to run premium gas in the 91 like the owners manual and the little stickers say, or can I run regular grade gas in it? It gets much better mileage than either one of our trucks but I can't justify spending the extra 20 cents a gallon. To me that just cancels out the better mileage. I need to know if we can run the regular grade, because right now, the vert is just a conversation piece sitting in the basement looking pretty.
If that is a great concern then you should have gotten a Yugo instead of a Corvette. Moreover, if you can afford to have a Vette sitting in the basement without being driven (I assume you still have to be paying insurance), doesn't it seem odd to be worrying about a few more cents for premium gas??
Last edited by DougSilver; Apr 20, 2006 at 04:09 PM.
Team Owner
Joined: Sep 2002
Posts: 22,209
Likes: 12
From: OBAMA IS HITLER
I'm going to say this again.
There's "premium" which is 91-92 octane.
Then there's what should be called "super premium" but often isn't, whether its at the pump or by many on this board. That would be 93 octane.
Your "average" LT1, with 10.5:1 compression, should NOT need 93 octane. Maybe that rare animal would because of poor build quality at the plant........
91-92 max; that's most all LT1's. Going higher is pizzing $$ away, and plenty at that. It has just about nothing to do with being "safe". Justifying 93 to one's self is like shooting at the bank account, blindly. As for that "safe" argument, you guys DO have a knock sensor, right????
There's "premium" which is 91-92 octane.
Then there's what should be called "super premium" but often isn't, whether its at the pump or by many on this board. That would be 93 octane.
Your "average" LT1, with 10.5:1 compression, should NOT need 93 octane. Maybe that rare animal would because of poor build quality at the plant........
91-92 max; that's most all LT1's. Going higher is pizzing $$ away, and plenty at that. It has just about nothing to do with being "safe". Justifying 93 to one's self is like shooting at the bank account, blindly. As for that "safe" argument, you guys DO have a knock sensor, right????
Burning Brakes
Joined: Feb 1999
Posts: 1,157
Likes: 3
From: Encino CA
Originally Posted by Hot Rod 90
91-92 max; that's most all LT1's. Going higher is pizzing $$ away, and plenty at that. It has just about nothing to do with being "safe". Justifying 93 to one's self is like shooting at the bank account, blindly. As for that "safe" argument, you guys DO have a knock sensor, right????
The octane ratings here in CA have not been above 91 for quite some time now. About a year ago I experimented when the local Union 76 station was offering "racing" gas that was supposed to be about 100 octane. At the time it was several dollars a gallon more than the standard pump. I put in maybe 2 gallons of this and filled up the rest of the tank with standard premium. I have to admit that I felt a difference--the car was definitely more responsive. I'm not certain what effective octane I got out of this mix.
Safety Car
Joined: Apr 2003
Posts: 3,793
Likes: 9
From: VA
Originally Posted by Tom Piper
"Be sure the posted octane for premium is at least 91 (at least 89 for middle grade and 87 for regular). If the octane is less than 87, you may get a heavy knocking noise when you drive. If it's bad enough, it can damage your engine."