Which fuel do you run?
Melting Slicks
Joined: Dec 2006
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From: Kingston Ontario
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Team Owner
Joined: Dec 1999
Posts: 34,873
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
But as far as running a lower grade like 87 or 89 octane, it's doable and the ECM will make changes depending on what it see from the knock sensor and the O2 sensors. Usually it will a retarding of the timing and maybe some changes in the fuel map.
I think the idea of "allowing" a lower grade is so that if you wind up somewhere needing gas and 87 is all that's available, the car will run on it. Just don't hammer on the car; very easy foot on the gas and don't load up the engine.
Le Mans Master
Joined: Sep 2013
Posts: 8,900
Likes: 1,074
From: Wisconsin
When I go on long trips when I rarely get over 65 mph and cruise AT 2000 RPM, I run mid grade, 89 octane. I am getting 27 mpg and since it does not knock there really is no need for higher octane. The only time you need premium is when you are running it hard. Premium is a waste for driving around town and cruising at 60 mph, lower grades will not hurt your car. Some folks are a little fanatical when it comes to gas. But it's there choice.
Some engines for which premium gasoline is recommended can run on regular without problems. That's because the engine's knock-sensor system detects the presence of uncontrolled burning in the chambers. When it does, the engine's computer-control system retards engine timing, eliminating the knock but slightly reducing power. If you don't mind giving up some performance, you can run these engines on less-expensive regular gasoline. To check whether your engine is capable of running on regular gas, read your owner's manual or ask your dealership's service department.
Last edited by JR-01; Dec 26, 2013 at 10:33 AM.
Team Owner
Joined: Aug 2003
Posts: 24,499
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From: Scottsdale AZ
Why would you ?
Not worth saving a few cents, especially on an older engine IMO.
There will always be those who say it's all a scam by Big Oil to make money, but there's definitely a difference in performance and fuel mileage.
Not worth saving a few cents, especially on an older engine IMO.
There will always be those who say it's all a scam by Big Oil to make money, but there's definitely a difference in performance and fuel mileage.
Last edited by CQRT; Dec 26, 2013 at 05:24 PM.
Melting Slicks
Joined: Aug 2006
Posts: 3,270
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From: Chilliwack B.C.
Chevron 94 for me up here. When I had my '88, I ran 87 quite a bit. Then I tried 94 for a tank and it made a huge difference - smoother and more power. I don't see a point to save a few dollars on fuel when I'm trying to get the car to perform its best.
Le Mans Master
Joined: May 2006
Posts: 5,814
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From: Pittsburgh suburbs Pa.
When I go on long trips when I rarely get over 65 mph and cruise AT 2000 RPM, I run mid grade, 89 octane. I am getting 27 mpg and since it does not knock there really is no need for higher octane. The only time you need premium is when you are running it hard. Premium is a waste for driving around town and cruising at 60 mph, lower grades will not hurt your car. Some folks are a little fanatical when it comes to gas. But it's there choice.
I alternate , regular then premium so it is mixed in the tank at all times . Also add Techron . I never run the car hard and it runs fine on that mixture.
Le Mans Master
Joined: Sep 2013
Posts: 8,900
Likes: 1,074
From: Wisconsin
Why not? It doesn't hurt anything. I got the same gas mileage with 93 and 89. The only time you really need premium is when you get on it. Lower grades will not hurt the engine and if you are going to drive it hard fill it with 93. Around town and cruising at 55, premium is a waste, it's not better gas, it just has more anti knock compounds. Too much anti knock compounds will actually reduce performance.
Melting Slicks
Joined: Mar 2008
Posts: 2,962
Likes: 254
From: Richmond, Ky
Since everything else I own runs on 87, I accidentally put some 87 in the Vette. It ran but would ping on acceleration and just was not fun. I got some 93 in it as soon as I could make room! If I can't afford the difference from mid grade to premium, I'll just park it.
Besides, I have a Shell card (Which I pay off every month).
