88 vs 90 octane

I am not sure I want to do that now. It takes an extreemly long time to do these tests. I can tell the difference in how the car performs with each fuel. the warm up cycle was shorter with the 92 and the mpg will climb on the trip mpg to over 90 mpg with 20 miles of in town driving the 87 will not do that. The reason I worked so hard on this last tank was to get into the 700 mile club. my average speed because all this driving in in town with 25-35 speed limit for 700 miles my drive time is like 30 plus hours. I have four children, I and my wife both work full time and with being on call 10 plus days a month, I hope you understand. I will continue to go back and fourth with costco 87 e10-vs-92 e10 so far this test is 6 months, I will do this for 1 year, after that I will probably just run the 92 e10 the cost per mile is less for me.

 

So are you running the tank completely out, to actual fuel starvation, as Bob Wilson has done for many of his engineering curiosity tests?

Or are you mixing the new fuel with a significant amount of the previous fuel, muddying the results?

 

Manufactures would lose sales if they put stickers on their cars indicating premium fuel equals higher MPG. Who wants to pay for premium fuel? Oh I guess I do

 

Use the grade that is recommended in your owners manual. By going to a higher grade you are just wasting your money.

 

........and Dr. Oz too.

 

^ I love the irony!....
Dr. Oz Grilled In Congress, Admits Weight Loss Products He Touts Don't Pass 'Scientific Muster'

 

There are two variables: (1) octane and (2) energy content. You are addressing octane in your comments, and I agree with your comment. But re: energy content- my understanding is both EPA and SAE (Society of Automotive Engineers) use correction factors to adjust observed MPG ratings based on fuel energy content. For example, 10% ethanol is a 3% energy content (MPG) debit.

For the average consumer, energy content is not important because it is just not worth it due to extra cost of premium. However XRAYDOUG and other Prius drivers are trying to set the world record for the most miles per tank in a Prius. Also trying to set MPG records. If they can get a little better energy content premium in their region (which depends on local EPA regs etc) they want to get it.

 

I only defined the term "octane."

The title of the thread is "88 vs. 90 octane."

 

^ I've never seen a 3% delta when using E0 versus E10, and I should be able to pick that up above the noise in the data.

I'm a little curious about the actual real-world benefit.
How efficient are ICE power plants these days, and how much of the additional three percent is turning the front wheels?

If you're trying to get a certificate with the word Guinness embossed at the top, then I guess you pay for the extra energy content but I presume that the actual benefit would be somewhere between 0.5 and 3 points.
Probably closer to the former.

One of the benefits on being me is that I don't pay for the gas that goes into my company car, and I live in a free state.
They let me pump my own gas, and it doesn't have to have alky-haul in it (although I suspect that much of it still does... )
I've tried several tanks full of the alleged alky-free stuff and I see no benefit.
That doesn't necessarily make me a 'denier'...I simply am not capable of measuring the effect.
Same with E10-87 versus E10-93.....although in fairness I've only burned through one tank of Premium in my company car since I don't want to take HEAT rounds for wasting their money on my chemical experimentation.

I am, and will remain very skeptical of any actual, measurable and repeatable efficiency benefit using higher octane fuel than your manual calls for.

It's nursery water for cars.

YMMV.

 

^^^I wish we could get access to a test track for one day, we could answer all the questions about fuels and tire pressure etc.

 

Ok, ok, the Esoterica Police are here. What does that mean in English, lol?

 

Sorry. I perhaps should have said "three percent change" instead of "3-percent delta"
It's a "me-ism" and perhaps (even probably) I used the expression incorrectly.
Symmetric difference - Wikipedia, the free encyclopedia


Ethanol is pretty self explanatory.
Ethanol fuel - Wikipedia, the free encyclopedia
E0 - no Ethanol
E10 - Up to 10-percent Ethanol.
At the pump...in the US, you look for a label similar to this one:

 

Then I am guilty too.

3% change means to me e.g., 50% to 51.5%
3% delta would mean 50% to 53%

 

I use most of the fuel each time. I have not ran out of gas yet. I drive past the 0 miles left every time. That way I get nearly 90+ % new gas. I am not sure exactly how much fuel is left in the tank and it is possible that running the tank dry could hurt the fuel pump because it is cooled by the fuel in the tank from what I understand.

 

Those who have tried had variances as great as 2.5 mpg. The backpressure that sets off the valve is not very precise in practice.

 

Exactly. Pumps are all different, even at the same gas station.

 

Those who have tried had variances as great as 2.5 mpg. The backpressure that sets off the valve is not very precise in practice.[/QUOTE]

It seems odd that my mpg always works out within 2% of the dash display and it is always less than dash display. I believe that if you keep track of you mpg like on fuelly your fill ups would have to average out a some point, even if there were these large errors. I don't believe I am having these type of issues with accuracy. in oregon we are protected from the dangers of filling your car with gas. I believe if you use a couple of gallons of gas and fill up the errors would be a problem. if you were switching back and fourth with different fuels you would end up with about the same gas all the time due to mixing with the existing gas in the tank. that may explain why others are seeing no change with different fuels.

 

I'm confident that Toyota has done better testing than any individual has done or will do here. I also believe if higher octane gave better mileage that Toyota would suggest we use it--or at least they would outline the benefits of using it and leave it up to us. After all, they would love to up those already high EPA mileage estimates further. That would result in selling more cars. So, color me skeptical if someone claims here they are getting some amazing mileage increase solely due to using a higher octane gas.

 

Every state seems to get a different formula for fuel. That would be nearly impossible for Toyota to test (if this is the case).