[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.

[surfinguy]

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.

This post has been edited by surfinguy: 11 July 2003 - 12:51 AM

[Costello]

bhp02, on Jul 9 2003, 09:25 PM, said:

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.

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.

This post has been edited by Costello: 10 July 2003 - 10:00 AM

[Costello]

quick_nick, on Jul 10 2003, 09:42 AM, said:

... is this even relevent?
i have a belly button :D

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

This post has been edited by Costello: 10 July 2003 - 10:03 AM

[tboner]

quick_nick, on Jul 10 2003, 10:30 AM, said:

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 assuming), 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/o...97/09/exxon.htm


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

http://www.boylework.../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/2...0/18/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 assumption 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.

This post has been edited by bhp02: 10 July 2003 - 10:09 PM

[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,
assuming 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.

[Paul Cherubini]

Dave, on Jul 11 2003, 02:21 PM, said:

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.