Refilled with non-ethanol 91 octane ...

[Hershey]

will see if any improvement . Refilled with 8.28 gallons of the 91 w/o ethanol . Eco showed 40 and there were 3 bars left . That would leave about 3 gallons of 87 w/ethanol . So not completely w/o ethanol :frown: . There were wet roads , winds up to 25 , plenty of hills , and temp in the mid 60s'. The 41.1 is getting home after the fill of 91 w/o E .

[edmscan]

Good luck in your quest .. however I filled my tank about a week ago with Shell "Gold" 91 Octane Ethanol free gas and so far ... I would have to say it is disappointing as I am not seeing any improved fuel economy. I think that I will be lucky to get as much as I normally do, but it will be a week or more before I know.

[Hershey]

May not help with the colder mornings . Had frost a few times .

[sickpuppy1]

I'd always been told that octane would not help mileage, unless what your running is too low for the engine requirements. IE: High performance engine require higher octane, low performance engine runs on lower octane, and running higher octane in a low performance engine does not help. Going ethanol free could help, yes, but arent all Shell fuels ethanol free?

[WeeYari]

There are some PetroCans in the Maritimes that offer ethanol free gas in all grades. Tried using ethanol free 87 while I was out there this past summer. Disappointingly, not a lick of difference in mpgs or detectable performance.

[Hershey]

The 91 was the only one without ethanol . The 87 + 89 have it . The gas stations with the 91 w/o E are about 47 miles away . Went shopping there . so stopped for a fill .

[edmscan]

Going ethanol free could help, yes, but arent all Shell fuels ethanol free?

Only the Shell Gold 91 Octane is Ethanol free, the "bronze" or "silver" contain up to 10% Ethanol.

Here in Alberta it is about 16 cents a liter more (or 61 cents a gallon more) for the 91 Octane vs the 87 Octane.

[Kaotic Lazagna]

Nothing about fuel economy, but may be some food for thought.

http://www.youtube.com/watch?v=gQghB4asSnI


Oh, and when ever I fill up with premium gas, I actually get worse gas mileage. I try to fill up with premium once a month for cleaning purposes.

[baseballfan416]

The way it's been explained to me, AND PLEASE!

Correct me if I'm wrong but...

Higher octane burns faster. Our cars are designed for a slower burn (hence, the reason most people don't see much benefit with higher octane). Yes, the compression is somewhat high for our cars, but the timing (primarily at higher rpms) is way too low for what it could/should be, and won't take advantage of a potentially quicker burn.

Meanwhile, the corn free aspect is of benefit because it burns at a lower temp.

Combine the two factors and it's basically a wash... If you could actually get corn free 87, it'd help because it'd be a slow burn as well as a cooler burn.

[daf62757]

There are some PetroCans in the Maritimes that offer ethanol free gas in all grades. Tried using ethanol free 87 while I was out there this past summer. Disappointingly, not a lick of difference in mpgs or detectable performance.

What are the "Maritimes"? Nova Scotia, St. John?

[edmscan]

I just finished my tank of Ethanol Free Shell V Power Gold gas .... and the results are well "Nothing to write home about". I got 638 km and 36.88 liters. This is 5.8 L/100 KM or 40.55 US MPG.

Interestingly, this is EXACTLY the same fuel economy that I got with "regular" 87 Octane 10% Ethanol gasoline.

So .... looks like the Ethanol free doesn't give you any better gas mileage. I watched a YouTube video recently and it showed that for cars like the Yaris, there is no difference in performance in the higher grade gasolines.

I think we have shown that there is NO benefit to spending the extra money to get higher grade gasolines.

[Hershey]

Just did a refill of SUNOCO 87 w/E10 . Took 9.358 gallons at 1 click and 386.3 miles on Trip B . Thus 41.28 m.p.g. with 91 octane w/o the E . There was about 3 gallons of VALERO 87 w/E10 still in the tank of the 91 w/o E . The Eco-Meter showed 39.5 and there were 2 bars left before the fill of SUNOCO .

[charles nelson]

Ethanol (10-85%) contains significantly less energy than 'pure non-ethanol' gasoline.
(Google it) My Flex-Fuel vehicle gets much better mileage, about 20%, with non-ethanol.
But here in MN, the non-ethanol usually costs more than 20%...so you get better mileage but end up paying more per mile. On a very long trip with the Flex-Fuel truck...I traveled a lot longer distance per tank fill in those states with non-ethanol. I have also tried 85% ethanol, at a much reduced price, but the truck's mileage sucked so badly that it wasn't worth the lower cost.

[mirapatec]

If the cost of the non-ethanol (pure) gas is equivalent to the cost of the E-10, I feel you would be better served running with the non-ethanol gasoline as much as possible. Just my 2 cents.

[Kar98]

will see if any improvement . Refilled with 8.28 gallons of the 91 w/o ethanol .

Gas with a higher octane rating will only improve your gas mileage if your car requires the higher octane rating because of a high compression engine like my VW Scirocco 16V. When I put in cheaper gas, it used more gas to compensate, and it ran like crap.

On the other hand, if your car is rated for regular gas, just use that, because you will not see an improvement in gas mileage.

[fnkngrv]

Gas with a higher octane rating will only improve your gas mileage if your car requires the higher octane rating because of a high compression engine like my VW Scirocco 16V. When I put in cheaper gas, it used more gas to compensate, and it ran like crap.

On the other hand, if your car is rated for regular gas, just use that, because you will not see an improvement in gas mileage.

Actually iirc even in the owners manual it states that you are not supposed to use non-ethanol gas whatsoever. Because of this alone regardless of the octane rating he very well may not be wasting money IF he gets that much better MPG out of it. I tried as much as possible when I was living in central AL to use the non-ethanol gas even though it was more expensive and usually after the first couple tanks netted on avg 3/4mpg better. Never bothered to do the math on the "savings" or "spending" but I can tell you that it ran better and I did get a much better response out of it. I really wish at this point that I would have been able to be tuned properly and had a solid dyno run to tell the difference if any between them. It just would have been intriguing to see if it were a placebo effect or not. :w00t:

[nookandcrannycar]

What are the "Maritimes"? Nova Scotia, St. John?

One of the most beautiful regions I've ever visited. Most people I know (Americans and others) use the terms 'The Maritimes' and 'The Atlantic Provinces' interchangeably for the combination of four provinces, but that is technically incorrect (I've never asked any Canadians I know what reference they use :biggrin:). The Maritimes include three Canadian provinces: New Brunswick (NB), Nova Scotia (NS), and Prince Edward Island (PEI). These are three of the four provinces of Atlantic Canada, which also includes the province of Newfoundland and Labrador (NL). With NL included, I spent about a month of the approximately four months I spent in Canada in 2006 (right before I bought my Yaris) in those beautiful Atlantic provinces. Another point of confusion is that St. John's is in NL and Saint John is in NB (and neither is St. John).

[jambo101]

Correct me if I'm wrong but...

Higher octane burns faster. Our cars are designed for a slower burn (hence, the reason most people don't see much benefit with higher octane). Yes, the compression is somewhat high for our cars, but the timing (primarily at higher rpms) is way too low for what it could/should be, and won't take advantage of a potentially quicker burn.

Meanwhile, the corn free aspect is of benefit because it burns at a lower temp.

Combine the two factors and it's basically a wash... If you could actually get corn free 87, it'd help because it'd be a slow burn as well as a cooler burn.

Actually Higher octane gasoline burn slower than regular grade gasoline, i'll leave you to do the research..
As the car is designed with economy as one of its main features the engineers who built the engine specify in the owners manual which gasoline to use for optimum performance in the engine they engineered.
Those thinking higher than needed octane levels are going to increase mileage and power have fallen into a very old marketing scheme/gimmick whereby the petroleum manufacturer gives the impression that the higher octane is a measure of quality instead of detonation characteristics,nice trick as many people go out and fill their cars with unneeded higher octane fuels and the fuel company laughs all the way to the bank.
http://www.handymanusa.com/articles/octane.html

[IFMJohn]

The whole higher octane fuel for fuel economy debate depends completely on the engine. Large engines tend to get higher fuel economy but only by 1 mpg or so. As far as getting more power by running higher octane fuel is a myth. And as far as running it to clean your engine out, again is a myth. Running a higher octane fuel cam actually cause buildup. Higher octanes have a longer burn time and require a higher pressure to fully atomize. Running higher octane fuel than designed can actually cause the fuel to not atomize causing the fuel to not fully burn. This can cause buildup and premature failure of emission components.

Its the good ol' "Some is good so more must be better." Except in this case it's not necessarily true.

[JustPassinThru]

I'd always been told that octane would not help mileage, unless what your running is too low for the engine requirements. IE: High performance engine require higher octane, low performance engine runs on lower octane, and running higher octane in a low performance engine does not help. Going ethanol free could help, yes, but arent all Shell fuels ethanol free?

Not anymore - by law.

In fact, in many states it's ILLEGAL to sell booze-free gas.

Higher octane doesn't increase fuel mileage when you increase beyond the design requirement. IOW, if you run low-octane gas in an engine designed for premium, the control module will retard the spark to prevent pinging; but if it's designed for 87 octane, running higher octane does nothing.

But removing the booze, increases the mileage. Because there's FAR less BTUs per unit of fuel in alcohol than there is in gasoline. Moreover, depending on the design of the ECUs, ethanol can mess up the feedback loop.

I haven't kept track; I avoid ethanol gas for other reasons. But I seem to get about 2-3 more miles per gallon with gas then with the odd rotgut tankful I've gotten.

[mirapatec]

I recently achieved 44.4 MPG on a tank of non-ethanol 87-octane gas. I was extremely happy. This is with an automatic transmission and city driving, by the way.

[albee213]

I once had a Dodge/Mitsubishi Cult 1980 something and it was a 4 popper, I used different grades of fuel in it while delivering pizza and kept tight records and found at that time it was breaking even running regular or premium becuase I was getting 1mpg more at every fill up and I felt it was worth it, I live in Seattle and there are nothing but hills here and the car was just happier going up them with with Prem. When ever I get a new car I start with low grade and then move up slowly to see the difference and not only look at mpg but how does the car feel when taking off from a light, going up a hill and listen to the idle, does it purr nice and even or is there a little stagger here and there.

Does anyone know the compression ratio for the Yaris, I keep reading its 10.5:1 and that would be in premium area for octane ratings. 8's are normaly low grade, 9's are mid and 10's are usually for high performance engines.

I just put a tank of mid-grade in my 07 Yaris and it feels a little smoother when I jump off a light and when passing on the freeway. I used regual and got 35 mpg, in a week or two I will see if there is a difference with mid-grade. One think I cant complain about is my last car was at the pump twice a sweek at $60, now looking at $40 every two weeks.

[IllusionX]

The 1nz engine is 10.5:1 compression. But does not need premium fuel.
Non-ethanol will increase mileage and overall peppiness of the car.

[Ben_]

In theory noon ethanol gas should give better fuel economy because it has more energy pet gallon. It takes about 300x more ethanol to produce the same energy as gasoline. This is assuming that 10% ethanol has does have that much ethanol

[why?]

ethanol technically will add power, because it makes the octane rating higher. In fact the Subaru community specifically tunes their cars for ethanol to get insane hp figures.

Non ethanol gas will get better gas mileage, but if coming from ethanol gas it will take a few tanks, because with ethanol comes water, and it takes a bit to get that out of the fuel system.

The compression has nothing to do with the type of fuel you need to use. Your numbers might have been great in the 80's but today the economy cars have higher compression ratios.

Oh, and I think my best gas mileage came on the crappiest gas in my region.

Octane really isn't about the temperature of the way it burns, because all gas burns at the same temp. It is about the consistency of when it burns. Higher octane gas is harder to ignite, but it will all ignite at the same time more often, whereas lower octane is easier to ignite, and might not quite all burn at the same time.

[albee213]

I have done some research on the Yaris 1.5 engine and it is a 10.5 to 1 compression ratio and in a normal circumstances that would require the use of high octane fuel.

Using modern technology they have found a way to inject fuel into the engine without causing early detonation by redesigning the head and fuel injection system.

Now after saying that, I am old school and to me 10.5 to 1 is a high compression ratio and to get what I think is the best performance out of this little rice cooker I only use mid or prem fuel, here on the West Coast its only .20 cents more per gallon for prem over regular. I was just in the South and did notice that the price difference between reg and pre was more like .60 cents, now that might make me change my mind as well.

[SirDigby]

this was interesting. looks like it died a year ago. Octane rating is the ability for a fuel to resist detonation under pressure. that's it. there are two different methods for testing this; the RON method and the MON method. then the results of the fuel tests are averaged. R+m/2. a modern ignition system will advance the timing to the point of knock or ping then retard slightly. that point depends on the fuel used. THE YARIS manual states use fuel with RON 91 rating.

[SirDigby]

ethanol-free fuel is awesome! my civic averaged 10% better fuel millage when E-free.
I just started to test my yaris at high altitude to see if the results are the same.

[ern-diz]

this was interesting. looks like it died a year ago. Octane rating is the ability for a fuel to resist detonation under pressure. that's it. there are two different methods for testing this; the RON method and the MON method. then the results of the fuel tests are averaged. R+m/2. a modern ignition system will advance the timing to the point of knock or ping then retard slightly. that point depends on the fuel used. THE YARIS manual states use fuel with RON 91 rating.

RON 91 rating is 91 octane?

I've had dudes go at me on here, basically laughing at me for preferring 91 octane. I've since tried some tanks of 87 and can't say I notice a difference in any measure other than my wallet. Still feels like I'm doing the old girl a disservice every time I pump 87, though lol.

[mirapatec]

I am still achieving higher mileage using the non-ethanol fuel. Around here, it is referred to as "marine fuel" since boaters use it.