Best gas -- premium? Ethanol free?

*sigh*
Here we go.

If that's a picture of Lake Ponchatrain in the background of your avatar, then you have access to E10, E0, Premium, etc.
(in some places it's a little more difficult to get non-ethanol gas, or E0)

This has been discussed, debated, fought over, and there are no conclusions that I can point to except to say that Priuses are regularly driven by people who swear by E0, E10, Premium and the cheap stuff.
IMHO, it really doesn't matter enough to justify an argument or the difference in price.

When Priuses first came out, there were all kinds of zany stories about them.
$5000 batteries.....
Not really "earth-friendly" through the life-cycle of the car....
EMF radiation hazard from the battery.....
You'll never recover the hybrid 'premium'....

Mostly?
It's what they call FUD.
Fear, uncertainty and doubt - Wikipedia, the free encyclopedia
People either exaggerate or make stuff up out of whole cloth.
IMHO, that's kind of the deal with ethanol and/or 'premium' fuel.

The people who designed and built your car recommend regular unleaded with (or without) ethanol not exceeding 10-percent.
There's anecdotal evidence that if you use "Top Tier" fuel that your car will run "better" and there is also some evidence that non-ethanol gas is 2-3 percent more energy dense than E10 (and usually 5-percent more expensive!)

That's a cute crumb-cruncher in your avatar pic.
Did you use nursery water with him?
If so then you paid about twice as much as people do for "regular" bottled water, and one HECK of a lot more than you would have paid for tap water.
...same thing.

FWIW....
I would NOT use "Premium" gas in a Prius, especially if you live pretty much at (or maybe even below in your case!) sea level. I like "Top Tier" gas stations because they're cleaner, and they probably do more tank and filter maintenance than the grungier Mom and Pop places.
Most importantly! They have better coffee and gedunk (snacks.)
I've tried E-0 for two tanks and saw no difference in MPG.
I don't personally believe that it will make any difference in the real-world efficiency or longevity of your car.


Your call.

Good Luck!

 

The mpg in my signature below is on E10 regular gas. No pulse and gliding used.

 

The best gas for a prius is usually regular at the busiest gas station in town, as it never gets time to settle.

If you do hill climb racing, there may be slightly better HP with E0 premium. But I question why you would buy a Prius for that sport.

Like every question you ever ask on Priuschat, it is hard to give a better answer without a location. US octane vs RON vs MON, E0 vs E10, mountain states get 85 Octane, etc.

 

This is a sensitive topic because Consumer Reports says all gasoline is equal, so it's hard for me to say that's a slight over-simplification (and get away with it).

For the vast majority of Prii drivers 99+% you are recommended to use Reg E10 and that is going to be great performance at the lowest cost. The E10 is expected to reduce MPG by 3% meaning maybe 1 to 2 MPG less on a Prius. So E0 might give slightly better MPG but they normally charge a helluva lot more for it, and often it's not a top tier or major brand. Toyota "supports" top tier dot com (TopTierGas.com).

Now if you are in the <1% of folks trying for a world record miles per tankful on a Prius, get back to me I tell some hints to maximize energy content and that probably includes E0 Premium in select locations.

 

There might be a 3-4% gain with E0 (pure gas) because the 10% ethanol contains about 4% less energy.

There is NO gain with premium (higher octane) because nothing in the design of the Prius engines will take advantage of the higher octane.

 

My life experience is that E0 (ethanol free) is the best because you get the most power out of each stroke and ultimately better MPG. Ethanol thins the gas, and while it makes a gallon of gas cheaper at the pump, it comes at a cost in MPG that pretty much negates its value...even more when you factor the energy required to turn corn into a gas additive.

It really doesn't matter, though. E0 or E10 will balance out fairly close in the end.

 

Before ethanol was added to gasoline, some now-banned chemicals were used (MTBE and tetra-ethyl lead) to satisfy the Clean Air Act.

So my question is, how does E0 satisfy clean air requirements?

 

From day one premium only, who knows if it is better or not but since filling up the tank of a Prius is only $30.00 bucks, I will spend the extra .50 cents per tank. I always get 55 mpg or more.

 

In my opinion, you're wasting your money. A higher octane rating denotes a slower-burning fuel, which has no practical advantage whatsoever in a conventional engine. Engines with higher compression ratios require Premium to avoid pre-ignition. Because it's a specialty product, it has usually been priced higher than Regular gasoline.

Of course, the oil companies don't mind one bit, if the motorist confuses the higher price with higher quality, and uses Premium instead of Regular, paying more. One might argue that they have even fed the myth by keeping explanations vague enough to allow people to assume the higher quality of Premium, without ever making such a claim.

Some companies may use different additives in Premium fuel, thereby providing some justification for the higher cost, but most brands don't bother with such distinctions.

 

"E0" would only be illegal if they were telling the truth about being E0.

 

By my reckoning, 4% of 10% equals about 0.4% less power by using ethanol versus pure gasoline.

I'd trade that 0.4% power-loss for a cleaner-burning engine any day of the week

 

The short answer is: E0 does *not* satisfy Clean Air Act requirements. The Clean Air Act (1990 Ammendments) requires that certain Metro regions must use so-called Reformulated Gasoline (RFG). All RFG now contains E10 (used to be ethanol or MTBE). That RFG region includes most of the East Coast thru parts of Virgina, CA, Houston, Dallas, Chicago area, and St Louis region. My guess is maybe 50% of Prius Owners live in a RFG region (including me).

More recently, during the Bush Admin, another law was passed to start requiring renewable fuels (E10) in ALL areas of the USA. The purpose of this bill was not to reduce emissions, but to reduce dependence on foreign oil. In non-RFG regions, some smaller companies are exempt from the mandate to blend E10 in all fuels. Larger companies may have also some flexibility to make a little E0 if they are meeting ethanol quotas or paying for ethnaol credits, which by the way quotas have not even been set yet by EPA for 2014. It's a hot button item.

Slightly longer answer:
Going back to the Clean Air Act 1990 Reformulated Gasoline decision to mandate 10% ethanol or MTBE to make gasoline burn cleaner, well, that was an extremely controversial so-called "bad science" decision by Congress. Congress/Industry had established a joint industry R&D program to measure auto emissions, and the new R&D data was basically showing that ethanol was NOT really required to make gasoline burn cleaner. This was an unexpected R&D outcome for Congress who then moved quickly to mandate ethanol/oxygenates despite the weakened case for actual need as far as emissions reduction. Fairly obviously, Congress wanted to go with ethanol for politcal reasons too.

PS- Greg I see you are in Canada...I am less clear on Canada rationale

 

There's something really strange going on in gas stations though, that I think contributes to the confusion.

First off, the expression "higher octane". Or "premium gas". Higher and Premium, yup, that's for my engine. Not "regular", run of the mill gas.

Then, count the pumps: one pump for the 95% of cars on the road that run just fine on regular (that word...), and two or three pumps for that 5% who's owner's manuals actual spec a higher octane. Why is that? Couldn't be the premium price could it?

And if you approach an attendant, and ask what he recommends? Here's a CBC expose on the subject:

Pump Fiction - Marketplace - CBC News

Hmm, that link's not working for me ;(

 

Here in the US, Consumer Reports has been saying to use Regular for quite some years. Sounds a little like Canada is not quite as avid Consumer Reports readers as we are? Another difference we have self-serve everywhere except NewJersey and Orgeon.

 

Over the years, I prefer to run tests with our Prius to determine what works and doesn't work. So this is what I found:

• Pre-E10 - there is a slight difference in straight gas, energy content:
• The 2003 Prius can slightly tune itself to exploit high octane fuel at high power settings but not reach the higher energy content fuel efficiency (i.e., power produced per unit of fuel.) This effect can be measured in the 2010 Prius in a maximum power, hill climb where higher octane fuel continues to burn while the lower octane fuel levels out:
• I was unable to find a density function with straight gas that gives an accurate prediction of the energy content. This was probably due to dissolved butane used in winter/summer blends but regardless of source, it means a field test is going to be more complex than just measuring the density:
• Both our 2003 and 2010 Prius will run on E50 without throwing a code. However, the mileage impact does not make economic sense in our region. E85 is NOT priced proportional to the energy content in Huntsville. In a similar fashion, E0 is overpriced for the energy content. In simple terms, the higher price per gallon means the cost per mile is not worth either one.
• The 2003 and 2010 Prius will run on E85 but as temperatures approach freezing, a cold engine may stumble in the first 15-20 seconds. Restarting the car and letting it run for a minute eliminates any subsequent engine stalls.

Understand I have no problem with folks sharing information they've found from other sources. Just I prefer to 'do my own work' and know what works or doesn't in our 2003 and 2010 Prius.

GOOD LUCK!
Bob Wilson

ps. Part of my gasoline studies is to empty the tank by running it dry with a spare, 1 gal. container of the next test gas. With the 2003 Prius, this is a non-event as there are plenty of warning lights when the engine won't run and I can use the traction battery to reach a safe place to park and add the spare gas. However, the 2010 Prius is 'silent' unless you monitor the energy fuel flow arrows which go away when the last of the gas is gone. Then I use the 2010 traction battery to reach a safe place to park and add the spare can. Toyota has a different opinion about whether this 2010 change is a safety problem.

 

Interesting video. An automotive expert uses Regular in his high-performance car, even though it calls for Premium. The computer compensates for any conditions which could lead to engine-knock, which is the only reason Premium exists.

The lady who paid extra for Premium, believing it led to cleaner emissions and less pollution, was surprised to learn that Regular actually burns cleaner than Premium, due to incomplete combustion of the Premium. This also leads to lower mileage with Premium.

It also indicated that the special "additives" claimed to justify the higher cost of Premium are nothing more than detergents, which the government mandates to be put in all gasoline, and putting in "more detergents" has no added benefit. The government has issued warnings to companies who make any claims that Premium is superior to Regular for deceptive advertising.

In spite of all these facts, the myth continues; and all gas attendants in the video (except one) recommended using Premium when asked, claiming all sorts of wonderful benefits which have been proved not to exist.

 

Greg, did that marketplace video play for you? Neither my or your links play for me, either on my win 7 ie11 desktop or iphone. I've watched it on cable though. Thanks for the summary!

 

It played for me, but it might be a Flash-video. Depends on your system.

Update: it worked on my Windows PC, but not on my iPad. Must be a Flash video.

 

Still feel that way after reading all of this?