Premium Gasoline
Drifting
Joined: Jul 2007
Posts: 1,294
Likes: 37
Sure can on later models!
If you have a later C4, (1995-1996) you can program it to safely run on 87 octane. in fact, Hypertech Programmer III has a specific program to set your car's computer to use 87 octane. However, you have to drive a lot of miles to recoup your investment.
i dont know about the other C4s.
i dont know about the other C4s.
Intermediate
Joined: Feb 2008
Posts: 49
Likes: 0
From: Langley British columbia
I always use premium (94 octane) in my 88, there's a sticker on the inside of my gas tank door that says to use minimum 93 octane, not sure If other years are the same. However with my L-98's 9.5:1 compression and aluminum heads I think I could probbably get away with a lower octane rating.
Intermediate
Joined: Apr 2008
Posts: 44
Likes: 0
I have a 89 C4 and i use premium everytime AND I use the Lucas fuel additive everytime I fill up. (A $10 bottle of Lucas lasts quite a few fill ups. Its only 3 oz per 10 gallons of gas). Dont cheat yourself, treat yourself! If you want performance, dont worry about the extra $20 bucks you spend a month, remember you are in every mans dream car! A VETTE!
Pro
Joined: Jan 2008
Posts: 584
Likes: 1
From: Near Lockport NY Black 1986 Coupe
If you have a later C4, (1995-1996) you can program it to safely run on 87 octane. in fact, Hypertech Programmer III has a specific program to set your car's computer to use 87 octane. However, you have to drive a lot of miles to recoup your investment.
i dont know about the other C4s.
i dont know about the other C4s.
And for everyone else out there, I will repeat myself - Higher octane WILL NOT improve performance. I don't know where everyone is getting this common ignorance of thinking octane means better, because it really only means the fuel burns slower. It will, and I can't stress this enough, DECREASE MPG if your compression is too low. The fuel will not be properly burned and the leftover will exit into the exhaust and mostly clog up the catalytic converter(if you have one).
If you really feel like wasting your money, I can't stop you, but atleast take the time to learn the truth. At one point I thought octane meant power, but I was wrong. It's a neccessity, not a bonus.
Race Director
Joined: Oct 2005
Posts: 11,772
Likes: 177
From: Rolla Missouri
2021 C4 of the Year - Unmodified Finalist
St. Jude Donor '10 thru '25
Actually, since the higher octane burns slower, it decreases the MPG because it doesn't fully burn the fuel on exiting the chamber. Unless you are running CI heads and have compression higher than 9.5:1, you can use 87 octane and not see any lack of performance. Aluminum heads can be run to ~10.5:1 on 87, but at that compression I'd recommend 89 or 91 anyway.
All octane is, is a resistance to knock. The fuel burns slower so the mixture does not pre-ignite in the chamber at the higher compression. As you hit higher RPMs, if you have lower octane, it will start to ignite faster and may knock even if you are running adequate octane for that compression.
So, basically, you're fine with 87 until 9.5:1 on either heads, and 10:1 with aluminum. After that, it's your choice, but higher octane does not mean higher performance.
All octane is, is a resistance to knock. The fuel burns slower so the mixture does not pre-ignite in the chamber at the higher compression. As you hit higher RPMs, if you have lower octane, it will start to ignite faster and may knock even if you are running adequate octane for that compression.
So, basically, you're fine with 87 until 9.5:1 on either heads, and 10:1 with aluminum. After that, it's your choice, but higher octane does not mean higher performance.
I wouldn't trust Hypertech with making a programmer for a TV remote, let alone anything in my car.
And for everyone else out there, I will repeat myself - Higher octane WILL NOT improve performance. I don't know where everyone is getting this common ignorance of thinking octane means better, because it really only means the fuel burns slower. It will, and I can't stress this enough, DECREASE MPG if your compression is too low. The fuel will not be properly burned and the leftover will exit into the exhaust and mostly clog up the catalytic converter(if you have one).
If you really feel like wasting your money, I can't stop you, but atleast take the time to learn the truth. At one point I thought octane meant power, but I was wrong. It's a neccessity, not a bonus.
And for everyone else out there, I will repeat myself - Higher octane WILL NOT improve performance. I don't know where everyone is getting this common ignorance of thinking octane means better, because it really only means the fuel burns slower. It will, and I can't stress this enough, DECREASE MPG if your compression is too low. The fuel will not be properly burned and the leftover will exit into the exhaust and mostly clog up the catalytic converter(if you have one).
If you really feel like wasting your money, I can't stop you, but atleast take the time to learn the truth. At one point I thought octane meant power, but I was wrong. It's a neccessity, not a bonus.
Master__Shake_ has given the correct advice twice here.
All of the "Nothing but the good stuff for my baby" comes from people that don't really know the facts.
Instructor
Joined: Sep 2007
Posts: 207
Likes: 0
From: Exeter RI
I put 92 or better in my 93 LT1 because it says "premium recommended" under the gas door. I figured it wasn't worth the $4 a tank to defy GM. I assumed that meant 10.5:1 compression was the point at which higher octane gas was required to decrease detonation.
Corvette Enthusiast
Joined: Oct 2003
Posts: 524
Likes: 140
From: La Quinta CA
Every high performance car manufacturer on the market, whether it be from a US car manufacturer or foreign, tells you to use premium gasoline in their car. The Chevrolet Corvette is a high performance machine that was designed to run optimally on the premium blend of gasoline. I don't know all of the particulars behind why the GM engineers said that the high performance engines require higher octane gas, but since they designed and built the Corvette, I'm going to trust that they knew what they were doing and put premium in the car.
Instructor
Joined: Nov 2006
Posts: 195
Likes: 0
From: Stamping Ground Kentucky
I agree with Master_Shake_ and RollaMo-LT4. One of the reasons I like my L98 for just cruising around is that I can use regular fuel with the stock compression ratio. I think part of the misconception behind gas octane choice is because petroleum companies call the high octane "premium" so people assume it must be better somehow.
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Melting Slicks
Joined: Aug 2007
Posts: 2,619
Likes: 1
From: Salem Oregon
St. Jude Donor '09-'10-'11
Every high performance car manufacturer on the market, whether it be from a US car manufacturer or foreign, tells you to use premium gasoline in their car. The Chevrolet Corvette is a high performance machine that was designed to run optimally on the premium blend of gasoline. I don't know all of the particulars behind why the GM engineers said that the high performance engines require higher octane gas, but since they designed and built the Corvette, I'm going to trust that they knew what they were doing and put premium in the car.
Exactly why I put premium in mine, because it is recommended, and I am NOT willing to take the chance on putting in something that can damage it down the road. How many times have you heard, oh, well, you can eat this, cause its good for you, and down the road, 3 years later, they come back and say oh, by the way, we found out that this chemical we have added to it causes cancer? It could slowly eat away at the engine, and other parts, and we wouldnt even know it til its too late.I am not putting premium in "MY BABY" for no reason, I would love to pull up to the pump and put regular in it, but I figure, if I am going to drive a high performance car, I am going to treat it as such.
Drifting
Joined: May 2007
Posts: 1,440
Likes: 19
From: SW Chicago Burbs IL
Master_Shake_
I run 87 octane in my '89. Read the owner's manual - that's what's recommended.
Matthew
PS - I should add that's for my L98 - newer cars do require premium.
I run 87 octane in my '89. Read the owner's manual - that's what's recommended.
Matthew
PS - I should add that's for my L98 - newer cars do require premium.
Last edited by Matatk; May 1, 2008 at 12:41 PM. Reason: more stuff
Instructor
Joined: Apr 2003
Posts: 197
Likes: 0
Use premium gas because "GM Engineers tell you to"??? Aren't these the same engineers who designed many crummy palstic parts for the interior or made changing a tail light bulb a trip to the hospital??
Almost every car made suggest 91 octane. Just a CYA statement by the manufacturers. And as Master_Shake states, it appears the masses don't understate what octane rating really means or is use for.
This thread is starting to read like the 160 degree thermostate debate
Almost every car made suggest 91 octane. Just a CYA statement by the manufacturers. And as Master_Shake states, it appears the masses don't understate what octane rating really means or is use for.
This thread is starting to read like the 160 degree thermostate debate
Melting Slicks
Joined: Aug 2007
Posts: 2,619
Likes: 1
From: Salem Oregon
St. Jude Donor '09-'10-'11
Use premium gas because "GM Engineers tell you to"??? Aren't these the same engineers who designed many crummy palstic parts for the interior or made changing a tail light bulb a trip to the hospital??
Almost every car made suggest 91 octane. Just a CYA statement by the manufacturers. And as Master_Shake states, it appears the masses don't understate what octane rating really means or is use for.
This thread is starting to read like the 160 degree thermostate debate
Almost every car made suggest 91 octane. Just a CYA statement by the manufacturers. And as Master_Shake states, it appears the masses don't understate what octane rating really means or is use for.
This thread is starting to read like the 160 degree thermostate debate
Instructor
Joined: Apr 2003
Posts: 197
Likes: 0
If your engine knock, move up in octane. To try a lower octane is not ging to blow the engine up and if it doesn't knock you'll save some $$.
My mechanic use to work in the refining industry and sees no problem using regualr in my L98 unless it knocks, then suggest increasing octane.
As for using injector cleaner, have to be careful if the original Multitec are still in the car. If use an injector cleaner I was told Chevron is the best.
My mechanic use to work in the refining industry and sees no problem using regualr in my L98 unless it knocks, then suggest increasing octane.
As for using injector cleaner, have to be careful if the original Multitec are still in the car. If use an injector cleaner I was told Chevron is the best.
Instructor
Joined: May 2006
Posts: 143
Likes: 0
From: Chicago Illinois
I guess I can say it one more time this is a quote from an octane definition.
"Octane rating does not relate to the energy content of the fuel, nor the speed at which the flame initiated by the spark plug propagates across the cylinder. It is only a measure of the fuel's resistance to autoignition."
But if your car can run 93 octane, it usually has better additives and is the gas stations premium fuel. Run it all the time.
"Octane rating does not relate to the energy content of the fuel, nor the speed at which the flame initiated by the spark plug propagates across the cylinder. It is only a measure of the fuel's resistance to autoignition."
But if your car can run 93 octane, it usually has better additives and is the gas stations premium fuel. Run it all the time.
Pro
Joined: Jan 2008
Posts: 584
Likes: 1
From: Near Lockport NY Black 1986 Coupe
I guess I can say it one more time this is a quote from an octane definition.
"Octane rating does not relate to the energy content of the fuel, nor the speed at which the flame initiated by the spark plug propagates across the cylinder. It is only a measure of the fuel's resistance to autoignition."
"Octane rating does not relate to the energy content of the fuel, nor the speed at which the flame initiated by the spark plug propagates across the cylinder. It is only a measure of the fuel's resistance to autoignition."
If in doubt, only put 1/4 tank in. If it starts to knock for any reason, go back and mix in a half tank of premium and it should stop.
And if you'd like to prove me wrong, please run 87 in your precious stock L98s and tell me you hear a knocking. I will bet my car that you won't hear anything at 9 or 9.5:1 compression.
Edit: The exception may be 1991, but I'll assume they only ran aluminum heads.
Last edited by Master__Shake_; May 1, 2008 at 01:13 PM.
