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Tha would be simplistic and often wrong. It depends upon the car.
No, it isn't simplistic, nor is it often wrong. As I pointed out earlier, the energy density of a gas/ethanol blend is lower than pure gasoline. Lower energy density means it doesn't carry as much energy as pure gas does, so it takes more of it to travel a given distance. This is why most people experience lower mpg using the blend. It's an unfortunate side effect of the attempt to reduce the use of foreign oil by "growing" part of the fuel ourselves.
Use the recommended octane. Higher octane some increase fuel economy. However, some stations' fuel blend could reduce your MPG. I tend to stick with top tier gas rated stations and my MPG stayed the same with only a 2 mpg difference (varies based on traffic and weather). One day I decided to get gas from a cheap station to save a few bucks. Though I didn't vary my driving, my fuel economy dropped from a city average of 23 down to 20, so low it almost dropped to 19. My car is a V6 2003 Chevrolet Malibu with 104,000 miles. My city driving MPG is between 22 to 24. Highway is a rare trip and last time I checked, it came to around 32 MPG.
BBC's Top Gear did a segment comparing a Prius to a BMW M series sports sedan. They had the Prius driven as hard as possible around the track with the BMW merely keeping up behind the Prius. The Prius ran out of gas before the BMW. At the end one host asked, "are you saying the BMW is more fuel efficient than the Prius?" His answer was if you want to increase your fuel economy don't change the car, change the driver. Changing how you drive will make the biggest improvement to your fuel economy. A lead foot driver in a Prius will get horrible MPG.
No, it isn't simplistic, nor is it often wrong. As I pointed out earlier, the energy density of a gas/ethanol blend is lower than pure gasoline. Lower energy density means it doesn't carry as much energy as pure gas does, so it takes more of it to travel a given distance. This is why most people experience lower mpg using the blend. It's an unfortunate side effect of the attempt to reduce the use of foreign oil by "growing" part of the fuel ourselves.
You were not clear what question you addressed in your answer. I assumed you were answering the thread question --Does higher octane yield higher mileage. And the answer to that is depends upon the car. Some cars can change their tuning to take advantage of higher octane gas and get higher mileage.
I agree that all other things equal mpg for ethanol is lower because ethanol has lower volumetric energy density.
No, the answer is no... higher octane does not increase gas mileage.
If a car requires 91 octane, using 91+ octane does not increase gas mileage. Using 87 / 89 and relying on the knock sensor decreases gas mileage.
Make sense?
In cars with sophisticated ignition systems the spark advance can be automatically changed with the changing octane leading to higher mileage from higher octane gasoline. As I said your answer is simplistic.
In cars with sophisticated ignition systems the spark advance can be automatically changed with the changing octane leading to higher mileage from higher octane gasoline. As I said your answer is simplistic.
It is a simple question with a simple answer.
You are supposed to use the optimal octane for a rated car. In high performance vehicles, this is usually a higher octane (91+). You will not get better gas mileage by using higher octane. A low compression ratio N/A engine outfitted for 87 octane will not gain fuel economy by using 93 Octane.
It is a simple question with a simple answer. If engine takes X octane, X octane is needed for optimal fuel economy. Increasing X will not increase fuel economy. Decreasing X will decrease fuel economy.
You are supposed to use the optimal octane for a rated car. In high performance vehicles, this is usually a higher octane (91+). You will not get better gas mileage by using higher octane. A low compression ratio N/A engine outfitted for 87 octane will not gain fuel economy by using 93 Octane.
It is a simple question with a simple answer. If engine takes X octane, X octane is needed for optimal fuel economy. Increasing X will not increase fuel economy. Decreasing X will decrease fuel economy.
If I put 91 octane gas in my car I get higher mileage than if I put in 87 octane gas. Simple and QED
If I put 91 octane gas in my car I get higher mileage than if I put in 87 octane gas. Simple and QED
Nope. Your car's optimum performance is at 91 octane. That means 87 octane may be "adequate" but not optimal. If your car can run on 87 but recommends 91, it uses a knock sensor to retard timing. A car that can function optimally on 87 (base model, low compression econobox ) will see no increase in fuel economy by using a higher octane.
Like I said, octane does not increase fuel economy. Lower than optimal octane decreases fuel economy. There is a difference.
That is a common myth. Octane is nothing more that gasoline's resistance to detonation (precombustion due to high cly temp and or pressure). A higher number does not burn hotter. They all burn the same temp. The higher octane burns slower that the lower octane. Whoever told you it would damage your engine is full of it. If your car calls for 87 feed it 87 if you want to waste your money then feel free to use 91 octane. It will not hurt your engine but you may actually loose MPG and be polluting more due to the slow burning and possibility of an incomplete burn.
This.
And I'll add.
If you hear a vehicle knock and ping and generally run rough, it is usually due to the a/f being detonated by compression forces, not by the spark plug firing. Basically the engine starts firing out of whack.
If you hear knocking and pinging- you can try a move up to a higher octane rating to see if it eliminates it. Better yet- if you own a modern car and you hear knocking and pinging AND have been using the recommended octane rating of fuel in your car- it's best to have a mechanic check you car, specifically the knock detector system (if so equipped). This system should retard the timing of the vehicle to eliminate the problem.
If you think that using a higher octane fuel is going to get you better mileage- well your plain wrong. If you claim your vehicle DOES get better mileage from higher octane fuel, maybe you should switch BRANDS of fuel and stick to your recommended octane rating. Chances are your vehicle may not like the additives in a certain brands fuel mix.
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