Octane question
Thread Starter
Melting Slicks
Joined: Feb 2005
Posts: 3,465
Likes: 40
From: Auburn MA
Octane question
I have a bone stock 94 Corvette LT-1 Coupe 6 speed. Now that regular is just a hair under 4 bucks and premium is anywhere from 4.18-4.30 per gallon. What is the worst case scenario if i put 87 octane in it. The book calls for premium but what would happen if i put regular in it. Wouldnt the ECU just retard the timming so it wouldnt premature detonate. So worst case scenario it just wouldnt put as much power to the ground.
Slingshot
Joined: Dec 2001
Posts: 3,817
Likes: 24
From: Charlotte NC
Best case scenario = less power and some minor engine pinging or knock; if you keep your foot out of it.
Worst case scenario = significant pinging, significant loss of power and holes blown thru top of pistons. This is the worst that can happen with prolonged engine knock.
Worst case scenario = significant pinging, significant loss of power and holes blown thru top of pistons. This is the worst that can happen with prolonged engine knock.
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You're only going to save about $3.50 a fill up with the difference in price between regular and premium. To me it's just not worth the loss in performance for the little you save, especially if the car is not your primary transportation.
Safety Car
Joined: Feb 1999
Posts: 3,504
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From: Mexico Beach FL
If you look at the wording by the fuel filler cap, I think it says premium "recommended" -- it does NOT say premium "required."
Recommended means more power with premium and less with 87 octane.
Anyone with an LT4 out there, does it say premium "Required"?
Tom Piper
Recommended means more power with premium and less with 87 octane.
Anyone with an LT4 out there, does it say premium "Required"?
Tom Piper
Thread Starter
Melting Slicks
Joined: Feb 2005
Posts: 3,465
Likes: 40
From: Auburn MA
The car is my daily driver so it is driven every day unless i have the bike out. I am just wondering what is the worst thing that can happen. I want to run a tank of regular and see the performance and fuel consumption and see what happens then I will form my oppinion.
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
The 87 octane runs well in my 94. Its my DD and don’t really push it but really never heard any ping either. But the real questing is the 10% methanol (alcohol) blend that is now coming out. In FL I don’t know why they are pushing it so hard at this time.
Has anybody experienced a decrease in mileage or performance problems?
Has anybody experienced a decrease in mileage or performance problems?
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Instructor
Joined: Mar 2008
Posts: 118
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From: East Bridgewater Massachusetts
I live in Florida and I run premium in my 84. I ran some regular gas in her a while back and it was big difference. (not the best)
The pedal is a lot firmer and the motor runs much smoother with premium gas. Night and DAY. I would say to just run a couple tanks of Premium. Make sure the motor is running smooth again.
the pinging. Dont want
Take out a loan to cover the gas price. Premium in Florida is up at $4.11. Almost a foot long sub at SUBWAY.
The pedal is a lot firmer and the motor runs much smoother with premium gas. Night and DAY. I would say to just run a couple tanks of Premium. Make sure the motor is running smooth again.
the pinging. Dont wantTake out a loan to cover the gas price. Premium in Florida is up at $4.11. Almost a foot long sub at SUBWAY.
Melting Slicks
Joined: Feb 2008
Posts: 3,286
Likes: 6
From: Palm Beach
The 87 octane runs well in my 94. Its my DD and don’t really push it but really never heard any ping either. But the real questing is the 10% methanol (alcohol) blend that is now coming out. In FL I don’t know why they are pushing it so hard at this time.
Has anybody experienced a decrease in mileage or performance problems?
Has anybody experienced a decrease in mileage or performance problems?
It is Ethanol, not Methanol. Big difference.
Le Mans Master
Joined: Jun 2006
Posts: 5,642
Likes: 5
From: One day you're a Comet...the next day you're dust... Arkansas
The car is my daily driver so it is driven every day unless i have the bike out. I am just wondering what is the worst thing that can happen. I want to run a tank of regular and see the performance and fuel consumption and see what happens then I will form my oppinion.
Burning Brakes
Joined: Feb 2008
Posts: 1,168
Likes: 17
From: Iowa
I am burning 10% Ethanol (89 octane) in my LT4 for DD and it does just fine. I live in Iowa and have been using 10% Ethanol for in cars and trucks about 25 years and I have never got worse gas milage with it. I check it out against regular gas every time I go out of state. E85 will give you worse gas milage but I don't believe you will see a drop with 10% Ethanol compared to regular. I have never had a mechanical problem yet do to running 10% Ethanol . The only problems I have heard locally of were when it came out back years ago, people with foam floats in there carbs would have there float go to the bottem of the bowl. I dont own any corn fields so I'm not trying to promote the stuff, it's just that I've noticed (through coments on the web), that people in other regins are leery of 10%Ethanol. I dont know what you pay for it, but here its 10 cents cheaper and has 2 more octane points. Good luck with what ever you decide to burn.
Last edited by tixeon; Jun 2, 2008 at 06:39 PM.
Instructor
Joined: Apr 2003
Posts: 197
Likes: 0
This has been debate numerous times. Octane does not equal power but the resistance to pre-ignite or "ping". You should use the lowest octane that your vehicle doesn't "ping" at. The ECM may alter your timing to eliminate a knock but for normal driving most C4's could use regular.
As for 10% alchol or Ethanol, it causes problems with the original equipment multitec injectors.
As for 10% alchol or Ethanol, it causes problems with the original equipment multitec injectors.
Le Mans Master
Joined: Aug 2005
Posts: 7,392
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From: Merritt Island, FL
Le Mans Master
Joined: Dec 2006
Posts: 5,139
Likes: 482
From: H-Town Texas
My line of thinking is this, yes regular or mid grade may be cheaper. However, if the question is, will it cause damage? The next question is, if so, will I save enough to pay for my engine rebuild? Probably not. Is saving a couple of dollars at fuel up worth the risk? Not really.
Intermediate
Joined: May 2008
Posts: 49
Likes: 0
From: Binghamton NY
Mixture
The old 89 is certainly a big gas hogger compared to my Hyundai but to eliminate the pinging I am mixing 87 octane with 93 and ending up with something around 90 which does not ping.
Still not cheap, but an alternative to using the expensive stuff exclusively.
Good luck, its not gonna get any better soon.
Still not cheap, but an alternative to using the expensive stuff exclusively.
Good luck, its not gonna get any better soon.