Okay. I've been using 94 octane - but - I would imagine I really don't have to. What do you think? It's an LT1 so I'm guessing more people will say to keep using the 93 octane. How much of a performance loss would there be? Would I get less mileage to the point where I might as well use premium?
What type of gas should I be using in my '95 Fleetwood?
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04 CTSV 500rwhp, 96 FTS-V T56 previously, 95 T56 Impala SS
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In that car, anything more than regular (87 octane), and you're just wasting money. Just go to a quality gas station, like Mobil or Texaco, and stay away from "Joe's Gas" and you'll be fine.
Any engine that was not designed with high octane in mind is fine to run on regular. If your car requires premium, the manual will say so. The only exception to this rule is if you have altered your car or programmin in any way that you would require premium fuel to prevent detonation. Such as in my case, where I changed cams and advanced my timing... Or if you raised your compression ratio or what not...
And Sal, I hope you realize you just opened a HUGE can of worms here... There are people who are adimant that you run the highest octane you can ALWAYS... And this debate will go on forever...
Any engine that was not designed with high octane in mind is fine to run on regular. If your car requires premium, the manual will say so. The only exception to this rule is if you have altered your car or programmin in any way that you would require premium fuel to prevent detonation. Such as in my case, where I changed cams and advanced my timing... Or if you raised your compression ratio or what not...
And Sal, I hope you realize you just opened a HUGE can of worms here... There are people who are adimant that you run the highest octane you can ALWAYS... And this debate will go on forever...
Bill's right, there is a lot of disagreement on this subject. So rather than bore everyone with another debate, I'll just give you some food for thought and then let YOU make up your mind. Just remember that my statements are backed-up by my experience over 20 years in the business and that included buying gas for our own pumps on-site, not hear-say, or just "something I read on the internet".
Fact #1. Buying fuel from a "name-brand" station DOES NOT assure you of anything as far as quality of the fuel, or it's accuracy as far as the octane.
Fact #2. You can purchase two samples of 91 octane fuel from two different stations and they MAY perform quite differently in your car. One MAY provide more anti-knock protection than the other.
Fact #3. You can buy two samples of the SAME fuel from the SAME station over a period of a couple weeks and it MAY test completely differently.
Fact #4. The actual test for octane is so expensive that virtually knowbody does it and therefore you are NOT quaranteed what octain you're buying no matter what it says on the pump.
Fact #5. Any vehicle with computer-controlled timing that utilizes a knock sensor will pull timing as it needs, but the system has a very limited scale to work with. In other words, it's possible that the knock sensor and PCM might not be able to pull enough timing to stop the detonation. And the opposite is true as well, the system will only INCREASE timing to the limits of the programming which will be determined by the OEMs fuel recommendation. In other words, once the timing is at max scale, adding extra octane is of little value. The problem is, I don't know any people that are monitoring their engine management systems constantly to be sure of what the computer has the timing set at and how much knock retard is being utilized at any given moment.
Fact #6. You CANNOT hear detonation in most cars until it is fairly severe.
Fact #7. Even a slight amount of detonation can destroy an engine.
Fact #8. ENGINES ARE FRIGGIN' EXPENSIVE!!!!!
My rule of thumb is to run at least one grade higher than the OEM suggests due to deviation in fuel quality which is absolutely common in the industry.
Fact #1. Buying fuel from a "name-brand" station DOES NOT assure you of anything as far as quality of the fuel, or it's accuracy as far as the octane.
Fact #2. You can purchase two samples of 91 octane fuel from two different stations and they MAY perform quite differently in your car. One MAY provide more anti-knock protection than the other.
Fact #3. You can buy two samples of the SAME fuel from the SAME station over a period of a couple weeks and it MAY test completely differently.
Fact #4. The actual test for octane is so expensive that virtually knowbody does it and therefore you are NOT quaranteed what octain you're buying no matter what it says on the pump.
Fact #5. Any vehicle with computer-controlled timing that utilizes a knock sensor will pull timing as it needs, but the system has a very limited scale to work with. In other words, it's possible that the knock sensor and PCM might not be able to pull enough timing to stop the detonation. And the opposite is true as well, the system will only INCREASE timing to the limits of the programming which will be determined by the OEMs fuel recommendation. In other words, once the timing is at max scale, adding extra octane is of little value. The problem is, I don't know any people that are monitoring their engine management systems constantly to be sure of what the computer has the timing set at and how much knock retard is being utilized at any given moment.
Fact #6. You CANNOT hear detonation in most cars until it is fairly severe.
Fact #7. Even a slight amount of detonation can destroy an engine.
Fact #8. ENGINES ARE FRIGGIN' EXPENSIVE!!!!!
My rule of thumb is to run at least one grade higher than the OEM suggests due to deviation in fuel quality which is absolutely common in the industry.
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