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Fuel grades



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bhp02

Paul, I have 2 friends that are chemical engineers

and they only use premium in their toyotas.

For the most part, I agree with you on fuel grades.

Eventhough because of my short term view, I use

regular. It seems that this board is sometimes very

hostile but keep up your advice. Although I may

not agree all the time,. your opinion is valuable.

i was looking at a shell site, and shell says that using premium gas will not extend engine life , and many other toyota dealers actully told me that using premium on "corollas" will sometimes reduce fuel economy because of something not burning right??. My point is that using regular on corolla engines will not hurt the engines nor cut the life of the engine. It all comes down to the brand you use, because all gas is not created equal.

Paul, I have 2 friends that are chemical engineersand they only use premium in their toyotas.

 

For the most part, I agree with you on fuel grades.

Eventhough because of my short term view, I use

regular.  It seems that this board is sometimes very

hostile but keep up your advice.  Although I may

not agree all the time,. your opinion is valuable.

Thanks for the input bhp2, Friendly question:

 

Are your ChE acquantances in (or experienced in) the oil industry? If so I would value their input.

Good discussion on the topic!

If Paul is right ( I have no data on the subject) about more detergents and performance additives are in the higher octane product, it is logical there would be a long term difference. I burned only Amoco premium in my 280ZX for years. I got cheaper as I got older.

Guest quick_nick

in australia we just have unleaded petrol, and high octane fuel for drag uses... now im not too sure what u people are on about but i know that it the little fuel gauge is on e, i have to visit the local shell and top it up... is this even relevent?

i have a belly button default_biggrin

... is this even relevent?i have a belly button default_biggrin

Wow, you got cars? I thought it was all kangaroos and koalas default_blink

 

Seriously, there's only one grade of unleaded? We typically have three grades of unleaded in the US (87 to ~93 octane).

What is the octane rating of the unleaded down under?

Guest quick_nick

i think its about 98%... which is pretty high isnt it?

im not all that knowledgable about petrol... as i said,,, i only care when that annoying light comes on..

tboner

i think its about 98%... which is pretty high isnt it?im not all that knowledgable about petrol... as i said,,, i only care when that annoying light comes on..

There are two ways to measure octane or shall I say there are two octane numbers commonly used. Those two are RON or the Research Octane Number and MON the Motor Octane Number.

 

What you see on gas pumps in the USA is an average of the two numbers or (RON+MON)/2

I don't know which is greater, but typically the spread between the two is 10 points.

So your 87 Octane gas may be (82+92)/2 which gives 87. (Note, I'm not saying RON will be 82 and MON will be 92, but if I got it right, it was a lucky guess, one number will be around 82 and the other around 92)

So many places in the world only display one of those numbers, so it makes it look like their fuel is a higher octane fuel.

However, when calculated using the same method used in the states, they usually come out to around 92-94 octane.

FWIW,

TB

bhp02

one chemist was a graduate in University of Manitoba/Canada,

He wanted to and was preparing to work for the oil industry, but it went bust

some 10 -20 yrs ago just as he graduated. Now he is just doing computer related work.

So he is out of touch, although I have yet to ask him

detailed questions and I don't know what post grad

research he has done.

The other chemist is with a paint company.

So the answer is no, they are not in the

petrochemical field. Most in the petro field

are in western Canada

(I am ****uming), while I live in Ontario Canada.

Regular Joe

Normally, I'm skeptical of the information from fuel companies, but when it comes to determining the limits of their own products, I would recommend trusting their documentation. I'm sure that if their high octane fuels could produce better economy, significant power increase or increased engine cleaning in 87 octane rated engines, they'd market those facts. They have tried in the past, but have been caught and convicted of false advertising (EXXON).

http://www.ftc.gov/os/1997/09/exxon.htm

Additional information from a second source fuel company can be found here (76).

http://www.boyleworks.com/ta400/psp/Mythsgas1.html

If you don't trust the engineers working for the fuel companies, you could always check out a media source (CNN).

http://www.cnn.com/2000/fyi/real.life/10/18/gas.costs/

Cheers,

Regular Joe

bhp02

I just had enough time to readhttp://www.ftc.gov/os/1997/09/exxon.htm,

don't have time to read anymore.

But I did not get involved in the discussion

about additives or

cleaning ability of the premium gas.

I have no facts to base an opinion on it

and if I vaguely implied it I could be wrong.

Also, I do make an ****umption that the

cleaner burning gas(in terms of leaving

deposits) would be the higher octane

although I have

no idea what the figures are and

whether it would be significant

and I guess by the ruling, the figures were

not significant enough.

bhp02

I think if you read all 3 articles carefully,

there is NO arguement that the higher octane

gas has the same useable energy as

regular.

Again, I believe that the higher octanes

(most) do have more and you get

better acceleration and mileage

from my personal experience.

But in my case, I decided not to use it

because the money spent did not seem

to be worth it. And I did mileage comparisons

under different conditions.

The oil companies do have to put something

extra or different in their premium blends otherwise

they would easily get convicted with fraud.

Regular Joe

Hello All,

Hopefully, this is my last post on this topic. Most of you won't care about the details, but for those of you who really, really want to more information about why "high octane fuel does NOT release more combustion energy or improve the performance of lower compression engines" (ie. the 87 octane designed Corolla engine), I'll save you the pain of wading through the P-V diagrams and point you to page 6.

http://www.aeromech.usyd.edu.au/MECH3201/d...o%20Lec%207.pdf

On the other hand, if you ever wanted to know exactly how a spark ignition engine worked, this is a pretty good basic rundown of the dynamics with some informative pictures and diagrams. Just don't get lost in the math.

Cheers,

Regular Joe

bhp02

there is a qualification that the engine is lower compression

for it not to have effect with higher octane. in the above article,

****uming the article is sustantiated.

Where does the corolla 03 engine belong

in the compression classification of the article ??

I do not know . does anyone know ??

Dave

I will add that I have spoken with two engine designers who back up what it says in the owner's manual...use the grade recommended for your car. That's 87. Higher octane levels may or may not have more detergent - hell, you can always buy Techron now and then - but they are formulated for anti-knock and that changes their burn characteristics as detailed earlier.

I will add that I have spoken with two engine designers who back up what it says in the owner's manual...use the grade recommended for your car. That's 87.

This is a Toyota forum and all Toyota owners manuals for the past 30 years have said:

 

"Select octane rating 87 OR HIGHER"

and/ or "use gasoline that has an octane rating NO LOWER THAN 87."

In addition, Toyota owners manuals have a section called "Operation in Foreign Countries" There it says:

"confirm the availability of the correct fuel (unleaded and MINIMUM octane rating).

Thus the Toyota factory engineers consider 87 octane the MINIMUM acceptable octane, not necessarily the recommended grade.

Sure it might be a Toyota forum. But all cars work on the same basic way.

I still have yet to see any proof provided by anyone, saying that with high grade fuel, you will get 500k+ miles without any problems. Or anything saying that lower grade octane fuel will cause fuel problems. If the higher octane fuel was any better. You would think auto manufactuers would put in this the manual. Suggesting to use a high octane fuel.

Lethal 7

Isn't that what 87 octane or higher means? Otherwise they should say use 87 octane ONLY. It's not like 87 octane is hard to come by, if anything the higher stuff is hard to come by so why mention 87 or higher then? Unless they are saying use higher, but it will work on 87?. Anyways......the beat goes on...

bhp02

Yes, If

I could get the premium cheap,

I would put premium. They do boldly

advertise that the premium blend with

petro canada has additional cleaners

although I am not familiar with any legal

issues related to that advertising.

The only problem I have with where

I live is that the motors and trannies

on toyotas outlive the body(destroyed from rust)

even with regular fuel. Typically at 150-200 k miles

rust up.

Of course other cars like my chrysler, the body will

last longer than the tranny and engine.(100k)

the manual says 87 or higher just for the sake of elasticity. But it has nothing to do with quality. I have done soooo much research on this topic, and both toyota and shell say that using premium has no advantage whatsoever on the engines life. Premium is for high powered engines that need the extra power because the car is big or a racer(luxurie or sports cars). But Econo cars like civics and corolla's do not need premium, regular is actully the (recomended) grade and if not (because maybe regular ran out or someone felt like putting mid grade) putting the higher octanes will still be fine. But u will be wasting money and thats it. If u want to keep your engine clean use BRAND names like shell, that is what i use and i love it.

I hope this makes sense.

The higher octane, the harder it is to burn the fuel. Remember that. The lower octane, the easier it is for the fuel to burn. The reason higher performance engines need higher octanes is so that the gas/air compressed mixture does not ignite before the spark comes, which is known as predetonation/knock..whatever. By using a higher octane, these engines DESIGNED FOR HIGHER OCTANE can get more engery from the gas. If a lower octane was used, the mixture would ignite from the compression, heat, or whatver else that is not hte spark and slowly destroy the engine.

Now looking at a corolla motor, it was designed to run on 87. If you put any higher octane in there, you are requiring the ignition system burn a mixture which is more resistant to burning THAN IT WAS DESIGNED FOR. That is why they say that you will not get any extra performance by using higher octane in engines which do not require it. However, there are environmental variables which we cannot control...if for some reason the engine is predetonating at 87 octane you should move up. Im not very familiar with the corolla engine, but im sure there is a knock sensor on there which will detect knock and retard the timing if the engine were to knock. If this was the case and you fill in a higher octane fuel, you will most likely notice an increase in performance since the engine does not have to hold itself back.

Lastly, I have heard rumors that some honda engines such as the v6 in the accord is designed to run on regular gas, but will actually step it's performance up if a higher octane take advantage of the higher octane. Would toyota do this...maybe....but in a corolla, I doubt it.