Additive vs. high grade gasoline



That’s why I said “basically”. I wasn’t referring to aviation fuels or fuels over 100 octane. I was referring to fuels blended for normal automotive use.


So am I. There are many components used. There is not enough isooctane and heptane in a barrel of oil to make near the amount of gasoline that actually is produced. Octane specs are met by adjusting the complex mix of components, not a simple C7/C8 ratio fix. More info here:


I looked, didn’t find it. What’s the main point? That most cars do fine without the added detergents?


If that was true, then gasoline would odorless, just like all the other organic compounds that end with the suffix “ane”. Methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane, etc.

A mixture of 2,2,4, trimethylpentane and n-heptane is a reference fuel that gasoline blends are compared to in order to determine their octane ratings.
2,2,4,trimethylpentane is a particular isomer of octane that has a fairly high antiknock property, it’s also known as iso octane.
Straight chain or n-octane has an octane rating of nearly zero.
There are fuels that have higher octane ratings than iso-octane, methane for example.

Octane ratings higher than 100 are extrapolated by how much the power of an engine can be increased by supercharging before detonation occurs compared to 100 octane fuel.


Wow! Guess I really blew it on that one. Looking at several articles online I see there can be over sixty components in gasoline and that octane rating is just an octane/heptane ratio equivalency. Thanks to all for straightening me out. My apologies.


NOVA archives only go back 20 years, that episode isn’t shown on their site.


Interesting to know. I always thought the iso-octane being referred to in gasoline lingo was the one with a single penultimate side chain.


But it’s this one instead, eh?


More proof I was never any good at organic chemistry!! … lol


One of the main reasons that those two particular hydrocarbons are used as a reference fuel is that they are both easily synthesized in pure form through chemical reactions as opposed to attempting to distill them out of a natural mixture of hydrocarbons.

In general, highly branched compact molecules resist detonation better than long straight chain noodle molecules. The long noodle molecules are easily fractured by heat into two free radicals that are so chemically reactive that they just spontaneously ignite.


That’s truly unfortunate.
But I watched the special perhaps five years ago. They described the entire fuel distribution system from the refineries to the gas stations, went deeply into the chemistry, and went into the labs of the major companies that develop the additive packages, as well as into the chemistry of the additive packages. Turns out that while the major companies each have their own labs, the chemistry of the additive packages have basically all evolved over the decades to be the same package chemically.

If someone wants to use only Top Tier gas, that’s fine with me. I’ll support their right to make that decision just as I’d support their right to buy their preferred brand of toothpaste. But in reality, it’s all just marketing, product differentiation in its purest form.

Feel free to buy and, if you’re a “believer”, promote Top Tier gasoline. I’m going to continue to feel free to occasionally point out that it’s marketing and nothing more.


This is from the 2017 Toyota Camry owner’s manual;

Toyota strongly recommends the use of Top Tier Detergent Gasoline. For
more information on Top Tier Detergent Gasoline and a list of marketers,
please go to the official website

Do you believe that Toyota is being paid to promote Top Tier gasoline?

There is a History channel program on gasoline that explains the pipeline distribution system and shows the oil companies additives being added during truck tanker filling.


I believe Toyota and Top Tier have a business relationship.
Toyota is sold all over the world. Do you think Top Tier gasoline is available all over the world? If not, do Toyotas suffer problems all over the world that they don’t suffer here? If not, can you explain why? What did the history special say about Top Tier? Anything at all?

A friend just bought a new cloths dryer. The dryer manufacturer recommends Fabreeze. Do you think it’s really necessary for her to use Fabreeze?

Have you bought your My Pillow yet? Do you really believe it’s superior?

Do you believe Purdue chickens are superior?

I could go on, but you get the point. It’s marketing. Developing relationships with the manufacturers of products that use your product are as fundamental as the product differentiation. And product differentiation is essential.


It’s a fact that Top Tier gas has more detergent than minimum spec allowed. And it’s a fact that several carmakers got together to set the TT specs. And I’ve seen tests results showing less deposits with TT gas. If you think that difference is insignificant that’s fine. But it’s not just “marketing”.


And I’ve seen an engine run without damage using only Slick50 and no oil.

Believe what you like. Meanwhile, I’ll continue to run my engines for hundreds of thousands of miles without problems. In over 50 years of doing so, I’ve never worn out a single engine. Not ever. Not one.

NOTE: “problems” does not include peripheral components. Or that OEM clutch that I had to replace on my truck at 295,000 miles. None of these things are affected by the gasoline.


Why would AAA back TT?

And CR found the AAA test results compelling:


Look, people, I’m not going to do this forever.

But it would be nice if one of you believers would tell me how Toyotas can run all over the world without problems and without Top Tier gasoline.

I don’t really expect and answer. Because there is none. So let’s move on.
I stand by my original replay to the OP: use what your owner’s manual recommends.


That is sufficient proof that better fuels are unnecessary, perhaps greater exposure to the auto industry would help to support your beliefs.

The History channel program predates the Top Tier fuel conspiracy, it was not mentioned in the program.


Back to the OP. Really? 20-30 cents/gal more? Where I live gas prices rarely vary more than a nickel between generic and brand name gas. The caveat most brand names require use of their credit card to get the best price. Again I am fortunate to have Top Teir certified station at a competitive price and they have non-alcoholic gas (not TT though) gas for my lawn equipment and outboard motor.


I rarely use TT gas…mainly because there isn’t a gas station convenient for me to use. Closest one is about 10 miles in the opposite direction of where I do 99% of my driving.

Is TT better?..maybe!..but that does NOT mean the NON-TT gas is bad. Nor does it mean that you can’t go hundreds of thousands of miles on nothing but NON-TT problem free - which we have. In fact I suspect that are MILLIONS of people in the same situation…and millions of vehicles world wide with hundreds of thousands of miles with no engine problems running exclusively on NON-TT gas.

There are so many people that say they only use TT gas and only the BEST Synthetic oil and only have the dealer service their vehicles…yet after 6 years and 90k miles they feel they need a new vehicle…jeez


Racing fuel is off road use only (wink, wink) and could be leaded a few years ago and exempt from road tax (which could explain the reasonable price). Of course that could have changed.


Maybe foreign gasolines have more detergents…