91 Octane w/Arco or 87 Octane with Chevron and other "name brand" fuel?

Is that a serious question ?
NO it's not the same thing at all.

A reasonable case can be made that fresher, newer oil is always "best".......and it is not unreasonable to have a calm debate about how often it should be done, both from a technical standpoint and for piece of mind.

The octane question, however, is quite different. Nobody nowhere who really knows anything about how gas engines work EVER recommends using a higher octane than the engine needs. NADA.....NONE.

Oil company marketing tactics have warped some people's minds. It seems that the damage is not reversible in come cases.

 

Yes it was a serious question albeit rhetorical. If you think the owner's manual knows better than everyone else what octane rating should be used in the car and then question the owner's manual's recommendation for OCI, it's contradictory. If that make sense to you then, you are right. There is no discussion here.

 

...in my mind, is not totally cut and dried.

Some of us live in EPA Reformulated Gasoline areas, which probably gives us a really clean Regular with detergent additives, but somewhat lower energy content. In this case we have no local access to E0. Re: Premium, I don't understand EPA regulations well enough to know if the Premium grade has to meet the same recipe requirements as Regular in reformulated gasoline areas, if so Premium would also probably be lower energy content. Re: detergents, apparently EPA requirements are not good enough, so TopTierGas.com stations add more.

For Orenji, I don't know what region he is in. If reformulated gasoline area, then I think Chevron Regular is fine for cleanliness. If not a reformulated gasoline area, then I am a little less clear on recommending against Premium as a hedge.

 

What ?? No discussion ??
Are you saying that you are right and I should sit down and shut up ??????

Yes I am saying that the owners manual is always right......barring a mis-print or similar error......but there are varying degrees of "right". Even the manuals specify different OCIs for differing conditions.
Not so for the octane recommendation.

I quit. Getting into the pointless region now.

 

Up here in Canada, the Owner's Manual (this is Toyota again) says to change the oil at 8000 km's (roughly 5000 mile) or 6 months. Just saying

 

No, I don't know if I am right or not. I only have an opinion. I'm saying if you think you are absolutely right, you should take your own advice. However, if you can entertain other opinions that are contrary to yours, then you can add to the discussion.

I would never ask you to censor your opinion. I actually encourage it. Especially on this topic because I agree with you.

iPhone ?

 

Keep in mind, on this web site, we do not bring in outside experts or Toyota experts to discuss technical topics. Also it seems, at least in the USA, we don't really see EPA and/or private industry experts being allowed to voluntarily contribute to these types of social media discussions. So in some areas like this we are stuck with sharing our own experiences, impressions and perceptions (and Consumer Reports etc.). The purpose would be trying to figure out valid best practices by sharing ideas.

 

Here are 5 articles that explain that unless you hear knocking, follow the octane specified in the owners manual.

Regular or Premium? - Feature - Car and Driver (best article, actual testing with examples where Premium does help)
Fact or Fiction?: Premium Gasoline Delivers Premium Benefits to Your Car - Scientific American (How could I resist Science?)
Paying a Premium for High Octane Gasoline? | Consumer Information (as close to Government advice as you will get)
When to Use Premium Fuel - KickingTires
Facts About Premium and Regular Gas

Now it is easy, find five modern articles that recommend Premium in cars that do not specify it. (this may have been true 40 years ago, so lets stay after 2000)

 

Regular or premium ?? Back in the day it was more interesting Sunoco had what they call a
BLENDED pump , ( with two tanks in the ground )
190 - Economy (87)
200 - Regular (89)
220 - Plus (92)
240 - Premium (94)
260 - Super 260 (96; originally 97.5)

Really ???? I never believed their claim to day I see the same tanker stopping at various
Branded stations filling their tanks .... really ??? Your fuel is better

 

I don't drive all that much - which begs the question why I paid extra for a hybrid... - but using premium fuel adds a dollar or two to my monthly fuel costs and [subjectively speaking] makes the ICE startups on my car smoother. I certainly don't expect it to give me any noticeable gains in fuel economy (nor am i going to bother comparing) and with the minor cost difference and no harm done to my car...i say...why not? But this is what works for me...clearly those who drive 20K+ miles/yr. would see a noticeable dent in their wallets for fuel costs.

 

The "placebo effect" is a powerful thing, in many different aspects of life.
I think that might be the first time I've heard "starts smoother" as a reason for using premium.

 

Re: Detergents
The very last article, at the end, talks about TopTierGas.com ... basically says Toyota does feel additional detergents are needed, that are found in TopTierGas.com brands. As far as I know, there is no longer any company putting more detergents in the Premium, so there is no benefit to Premium re: detergents. Presumably a few folks add extra detergents such as Techron if they feel they are needed (eg; due to use of non-top-tier).

Re: Energy Content/MPG
The first article said: "Premium does not necessarily pack more energy content" but I would add, Premium certainly could pack energy content in some cases. Because gasoline is sold based on an Octane spec, this means energy content is allowed to vary somewhat, in all grades. Presumably there could be stations where the premium tends to have more energy content than the regular, or vice versa. The only way to know this is with more data on the fuel (eg; density) or by experimenting to see if you get better MPG. Premium is so much more expensive, it probably would not pay to use it, even if it gave a little better MPG. But fuel energy content variations might explain some of the MPG variations that Prius drivers sometimes report.

I always use Regular TopTier but I might do an MPG experiment with Premium later this year.

 

Unfortunately the term "octane" has two entirely different meanings.

Statements like that, referring to the OTHER meaning and usage just clouds the discussion further and does nothing to clarify the most common meaning, which is a characteristic that resists compression ignition (dieseling).

 

? I am using the usual definition of Octane such as 87 Pump Octane (R+M/2)

 

Well then that last post made little sense at all.

It seems then that you are saying that the quality of this product might vary from one station to another or from one time to another.......and no overall conclusions can be made. Much like what can be said for ANY product on the market these days.

And you are saying that higher Octane doesn't inherently mean more (or less) energy content.
Which is what several others have been saying.

I can't decide who you are agreeing with.........if anybody.
Color me confused.

 

Edmunds.com has a pretty exhaustive list of premium recommended vehicles here. Save Money and Stop Buying Premium Gas
Midway through the article they mention a Chevy Cruze with the 1.4 liter turbo getting better fuel economy using premium in hot weather testing enough to save $ over the added cost. It's anecdotal but pretty interesting anyway.

If you do it, I look forward to the results of your experiment.


iPhone ?

 

As implied by Reference #1

"Premium does not necessarily pack more energy content"​

but the flip side of that statement is that Premium does probably tend to have more energy content, although it is not guaranteed to have more energy content. For example, ethnaol has high octane but low energy content.

The main argument for most consumers is: 87 Octane is good for almost all cars, even cars designed for higher octane probably cheaper to run on Regular. So Regular seems best for almost everybody these days.

The advanced topic is: even though Consumers Reports says all gasoline is equal, this is not strictly true. Energy content can vary; detergents can vary. Many little things can vary. As Prius drivers, we see a big 50 MPG hitting our eyes every day, and if a higher energy content gaso could give us 53-55 MPG, some would like to know that and fiddle with it.

 

Have experienced better performance using higher octane in my race car at Watkins Glen. Car was faster with Higher grade fuel. That means more horse power. Thats why the race cars use it.
At this years Green Grand Prix at Watkins Glen will run two Prius's a Gen 2 and a Gen 3.
You win by getting better MPG. Hopefully, level of Octane will not be measured. Will bring in my own gas.
Tires will be pumped up to 55psi, & any thing I can remove from inside will be left in the pits.
Starting to Diet now.

 

Good, because the diet will help more than Premium fuel.

 

SIGH.
One more time and then I quit.
That is NOT true.
If there is any difference in "energy content" so-called premium is highly likely to have LESS not more because the higher octane is usually achieved by putting additives into a lower octane base stock.

Those additives, like ethanol, always have a lower energy content and some like the tetraethyl lead that they used to use wouldn't burn at all......for an effective energy content of ZERO.