your thoughts on 87 octane gas

[Emil]

Axy, what I was just comparing the octane ratings due to the different knock indexes being used.

As for Western Europe I am a bit surprised. I thought in Germany the lowest rating was 89 ...mmh.. maybe 91!. But definitely not 95. Or am I wrong? Maybe time for a visit...

[lankeeyankee]

Talking about octane is like talking about oil, politics, and religion.
Everyone has there beliefs. I have been building, tuning engines for over 25 years.
To get the most power from a combustion engine.
The lowest octane before detonation.  Detention is pre ignition when the spark occurs before the piston is TDC top dead center on the power stroke.
97% of people think... Ahhhh high octane bigger explosion, faster burn clean.... right?  WRONG!!!!!
Lower octane has a faster flash point compared to "premium, high grade" fuel.
OK, for those of you that know about high compression engines used in race engines this application MUST use higher octane fuels to slow the burn rate down as the piston is coming up. Compression is will ignite faster then a lower compression engine. When I say race engines with high compression I am talking 13:1 + ratio higher. Such as diesel engines are VERY HIGH in compression so diesel fuel has a very low flash point or octane due to the compression will ignite the fuel.
So back to simplying this answer. By putting high grade fuel in your low compression engine such as 10:1 you are wasting your money and also forcing unburnt fuel through your valves and exhaust which leads to carbon build up.
There are many articles if you google keywords octane physics. I will say this,, high test fuels have detergents in them to keep the EPA happy but in actuality your doing more harm with carbon build up that your little scoot cant burn 100%
Use the lowest octane such as 87 octane if you dont here any pinging in your engine under a load/ If you do here a pinging move up to 89 but you should NEVER need high octane in a stock compression scooter.
Some will argue this and disagree cause when most here premium they think YEAH THATS THE BEST and i want the best for my scoot! The onlything premimum is the price you are paying at the pump.

http://auto.howstuffworks.com/fuel-efficiency/fuel-consumption/question90.htm

Ohhh but wait,, you say "My manual says to use 93 octane... BUT thats in ASIA and EUROPE where octane rating is different then fuel here in the US.. Read, educate before posting facts you think or have been mislead on.

[wordslinger]

Use the lowest octane such as 87 octane if you dont here any pinging in your engine under a load/ If you do here a pinging move up to 89 but you should NEVER need high octane in a stock compression scooter.

..sorry, but my a50 would strongly disagree...

[oswaldters]

Okay, so this is where I kick myself for having gotten involved in this.  But since I did get involved I will say this:

It's fine that people have different opinions and/or facts about something and have a discussion about it, but you can disagree with someone without having to insult them.

(and I'm referring to the "Read, educate before posting facts you think or have been mislead on.")

I think that was unnecessary and don't want to see another nasty thread started here.  

And as Forrest Gump would say "That's all I have to say about that"

p.s. thanks to Pedro for not PMing me a 'told you so".

[wordslinger]

...80% of what i say here is from my own experiences...

..10% comes from reading stuff...

..the other is mostly bullsh**...lol...

..some might argue about those percentages, but i reckon i cant stand to tell somebody something that has no fact as a base...

..every engine's setup IS different...what works for mine..well, it works!!!

..don't give a CRAP about what SHOULD be working, or whether or not it's the ABSOLUTE ONLY way...

..there are very few absolutes....

 


peace

[lankeeyankee]

Use the lowest octane such as 87 octane if you dont here any pinging in your engine under a load/ If you do here a pinging move up to 89 but you should NEVER need high octane in a stock compression scooter.

..sorry, but my a50 would strongly disagree...

Pinging is also caused by a lean condition. Which is very common with scooters brought to the US to meet the strict US EPA standards. Its not uncommon to see a performance increase by a simple main jet increase by 1 or 2 sizes.
So basically your masking the problem.  Rejet your carburetor properly and then you will be able to run lower octane fuel and have better performace.

Lean condition improperly jetted carburetor= not enough fuel ignites faster.
High Octane Fuel= Slower Burn.
Its all a timing thing.
Yes, you can fix your lean condition with higher octane fuel. Is this correct or is it the most proficient way, no.

[wordslinger]

So basically your masking the problem.  Rejet your carburetor properly and then you will be able to run lower octane fuel and have better performace.


..again...even when my scoot was fully restricted...just days off the showroom floor...93 octane fuel made a difference in how it ran...

 

...i jet my carb by means of performing and reading plug chops...

..it's the only sure way to assure that your engine is performing at it's optimum capabilities...

..there is no masking your plug...

[wordslinger]

Pinging is also caused by a lean condition


..i've never heard a ping...in my engine...

..to be honest, and you can read waaay back in my posts...i've always ran a larger main jet than ANYBODY else here, with an a50 ......probably still am, as i'm running a 1.02mm at @ 60 degree average temp...


 

[tomheet]

OH well, I'm thick skinned enough I guess. And its funny, cause all I did was quote what the manual recommended, not giving out mis-information. I will hang my head in shame LOL!! And, the reason i'm here is to GET educated! Thanks for the good info, including you lankeeyankee. I did not consider there might be differences in ratings in Asia versus the U.S

[wordslinger]

..i reckon i'd use what runs best in my scoot...no matter what the octane rating...


..And its funny, cause all I did was quote what the manual recommended, not giving out mis-information.


..no, all the info in the thread is true!!!...

 

..it just doesn't apply in every case...

..too many other variables...


peace

[lankeeyankee]

In Europe 98-octane gasoline is common and in Japan even 100-octane is readily available at the pumps, but this octane nomenclature is misleading to Americans as foreign octane ratings are derived entirely differently from our own...
Your scooter manuals are all written in another country which uses Research Octane Number (RON) to give there value of octane, here in the US we use Anti-Knock Index (ANI) to put a value on our octane.
So, with the commonality of RON in mind a good rule of thumb is as follows, multiply the foreign RON Octane rating by 0.95 and you will have the US AKI equivalent.
Example: If your foreign manual tells you use 92 octane you use a formula to convert to US octane which is achieved by, 92X.095= 87.7.. My scooter owner manuals says to use 90 so using the formula to convert to US octane I should be using 90X.095= 85.5 octane.

But seems we have much smarter folks here then scientist / engineers that have researched octane of fuel.
"My scooter runs better with higher octane" is the same as saying my scooter has more power and is faster when I drilled holes in my exhaust. Put it on a dyno and I guarantee you will see no HP increase.

"Aint my ride"

[juice]

[ScottNicol]

I have an a50 (same year as wordslingers I think), and I run 95 octane, which is the lowest I can find. Premium is usually 99 octane, which my friend runs all the time with his two stroke. The bike I have must have done around 9km with 95 octane is it is the lowest around, no damage, and it's very quick off the line. I might try 99 octane and see what sort of performance increase/decrease I get, but I don't think it will harm it.

[wordslinger]

But seems we have much smarter folks here then scientist / engineers that have researched octane of fuel.

..give me a break...


"My scooter runs better with higher octane" is the same as saying my scooter has more power and is faster when I drilled holes in my exhaust

..ain't your scoot, so i guess you just don't know, do you??

..i appreciate every bit of information that you're gleaning from various manuals and the internets and such..

..i still stand firm in saying i know how my scoot performs under various different conditions..

..horsepower notwithstanding..never said there was an increae in horsepower...

[oswaldters]

This is one of those things where you go with what works for you.  If the scoot is running well on whatever octane you run, then go with it.

Kind of a tastes great vs less filling debate I suppose, but people generally feel very confident that whatever they're using is working great for them.

You're not going to do any damage one way or the other.