Best brand of gasoline?

Gasoline is a commodity. A station will get whatever gas is most available. Even if it isn't from that brand's refinery. Even if from a brand refinery, the differences in the starting petroleum and refinery operation result in differences in the gasoline. All this means is that the gasoline at one station may not be the same as from another station of the same chain.

The only difference of meaning between brands is being Top Tier or not Top Tier gas brands use better detergents and other additives, that will help keep the fuel system cleaner in the long term.

Higher octane won't help in an engine not designed for it.

 

i thought the gen 5 engine was designed for it as an option?

top tier gas> /

 

Octane? There was that footnote about 91 octane for best performance in an early video. That could have been someone mixing up RON and AKI, and I saw that mix up on early gen1 Tundra labels. Most of the world, including Japan, uses RON on pumps. 91 RON is 87 AKI.

 

that's probably what i was thinking of, i'll never stop making that mistake

 

Walmart/Sam's w discount membership. Brand won't matter

 

I've found that ethanol-free gas (verifiable, from reputable source) provides superior performance, particularly on my Gens 3 and 4. Haven't driven enough on the Gen 5 yet to tell, but it came with a tank of adulterated gas, so will know soon!

 

Long term, top tier fuel will be the best for the car. On my last road trip to Spokane, I put in 92 octane just to try it. I thought it ran a little smoother but it could have just been the butt feel placebo effect. I still use 92 octane since it's so cheap to fill the tank.

 

Well, manufacturers do put high octane engines in cars, and say it is regular fueled for marketing sometimes. The 1.4L turbo in the 2013 Sonic was one such engine.

Cars run the engine at the cusp of knocking for best performance and efficiency. That can mean some preknock in the engine vibrations. An octane higher than the engine needs eliminates that potential running roughness. So the smoothness could be real. But that is about all the benefit for the higher price.

I think Canada premium is ethanol free, so there could be other reasons to pay more.

 

In the maritimes, Shell Premium 91 is usually ethanol-free, and only a nickel a litre more than the 87 Octane 10% swill. Car is obviously peppier and engine runs smoother and quieter.

 

Chevron's got a 4th octane level, their highest level, has a separate hose at the pumps, and a sticker saying ethanol-free. Ive tried it a couple of times: didn't really notice any difference.

 

In 2016 AAA did a little research that might be informative (if you’re interested, the actual results are written up in detail and are much more informative than just some of the condensed version). The pictures of certain parts of the engines might impress.
Nearly every one has an opinion on which brand is best, or if there is a difference between brands. So the AAA report will only inform those who realize a need to be informed. FWIW

 

Can get the PDF here, Fuel Quality (Top Tier) Full Research Report-July 2016 | AAA Newsroom

The results were pretty much what has been said here; using Top Tier gas results in less deposits. That keeps the engine running smoother, and at its best efficiency. Top Tier gas may also remove existing build up. It likely won't cost more to use it.

TOP TIER - High-quality Fuel Performance Standard - TOP TIER™

The AAA also tested out out the use of higher octanes.
Don’t Be Fueled: Premium Not Always Worth the Price | AAA Newsroom

For the Sonic, that price difference would make getting premium worth it. The difference here is double. That leaves the price per mile higher despite the efficiency improvement.

 

The comments mentioning that in some places higher octane gas having less or no ethanol is interesting and somewhat ironic to me because I had read years ago that adding ethanol to gas was an easy way to increase the octane rating. I believe that's why some people mod their cars to accept E85. I'll have to look for ethanol-free gas the next time I'm in Canada. It's possible I've used it but never noticed.

There is absolutely no reason to put anything other than regular grade in a Prius though. The ECU will not take advantage of it at all, since it's not a performance vehicle in need of higher compression.

Ethanol has less energy density, so from a fuel efficiency perspective, ethanol free gas should yield more miles per gallon.

 

Ethanol's effective octane is over 100, so it is commonly used to increase octane. The aforementioned Sonic has E85 fuel trim maps in its ECU, and some do convert to E85 or flex-fuel for the performance boost. Many race classes use methanol for the same reasons.

Gas isn't just used for cars. Other uses, like power tools and boats, weren't required to be ethanol compatible. They also tend to call for higher octane. To avoid potential issues for consumers, and to make ethanol free groups happy, some jurisdictions mandate premium octane fuel to be ethanol free.

 

Ethanol also introduces some oxygen into the fuel and reduces pollution. So yeah, going ethanol free will get you slightly higher mileage, but it's bad for the environment. Not sure everyone realizes that.

Oxygenate - Wikipedia

 

The EPA sets an oxygenate level for gasoline blends. Ethanol free gas has an ether or maybe butanol mixed in. I believe E7 is all that is needed to meet oxygenate requirments.

 

How many "Top Tier" refineries can you name?
(Hint: refineries advertise to a different audience.)

Good News!
If I'm accurately informed, the G5 does not have direct injection.
That means that you can just about 'run what you want to.'

MORE IMPORTANT QUESTIONS:

What's your oil capacity??
How often do you check your oil???
How often do you change it??
How often do you buy cars?

Gas preference is the LEAST important factor in determining car longevity.

 

IIRC it has both direct and port injection.

addendum: yeah:

Video on Toyota D-4S Direct Injection System(new for 2023 Prius) and does it work | PriusChat

 

In that case you REALLY do not want to be one of the......um......lesser informed people who try to pay more for E0.

MY mileage.
Real-world mileage WILL vary.