The pump must have a sticker on it stating if it's anything but 100% gas from oil. So you would see somewhere on the pump 10% ethonal or 5% xxx.

 

One more thing, buy your gas from a high volume gas station. I worked for a large Texaco dist. a while back and one thing i learned was that gas looses approx. 1 octane point for every 45 days it exists. If you realize how long it takes to get to your area of the country through the pipeline (especially the northeast), it may have lost 2-3 octane points by the time you get it home.

 

Chris,

Is that what they mean by saying oxiginated or non oxiginated fuels, is that it has Methanol or Ethanol alcohol in it???
So that 10 % would be gas that IS oxiginated????

Jim

 

Yes ethanol, methanol, and MTBM (or something like that) are called 'oxiginated fuel' addtives.

 

jimmy, so is NOS, but that is not an issue at the gas pumps....

 

q]Originally posted by: 2manytoys
I am a cert mechanic and can tell you that with out a doubt using higher octane fuel is a waste of money. Just because you put a higher octane fuel does not mean it will run better. In fact in most cases it will run worse or no change at all. Higher octane burns at a higher temperature and only works as it is supposed to in higher compression engines. A 12:1 compression will require a higher octane. If you use a low octane fuel in a higher compression motor it will melt. Most likely you will not notice any difference between 87-91,92,93 octane in a 4 stroke motor. 2 strokes run at a higher compression and to help with pre detonation it is recommended to use 91-93 octane but not the case in 4 strokes. A lower octane will combust quicker than a higher octane. 2 strokes you will get pre detonation with the lower octane fuels because it burns hotter but it will not burn all the fuel in the cylinder so you get the pre detonation.[/quote]

Agree and disagree

Agree:

"using higher octane fuel is a waste of money. Just because you put a higher octane fuel does not mean it will run better. In fact in most cases it will run worse or no change at all. Higher octane burns at a higher temperature and only works as it is supposed to in higher compression engines. A 12:1 compression will require a higher octane. If you use a low octane fuel in a higher compression motor it will melt. Most likely you will not notice any difference between 87-91,92,93 octane in a 4 stroke motor."

Disagree:

2-strokes run at a higher compression and to help with pre detonation it is recommended to use 91-93 octane but not the case in 4 strokes

I have never seen a 2-stroke run 12:1 compression from the factory. My WR426 has 12.5:1. For you non Motorcycle people a WR426 is a high Performance 4-stroke Off-road bike with 12.5:1 compression from the factory. Like most other high performance bikes like the YZ450/250,CRF450/250 etc. recommend 94 octane. No pump gas has 94 octane in my area, 91 or 93 is all. I run either of those and it works great.

Octane is the rating the fuel will burn without a spark. Diesels run low octane and high compression around 20:1 that's how they work with out spark plugs they rely on the detonation to run, a controlled detonation.

 

You all will probably tell me it's in my head, but I've been running 87 in my 700 Sp EFI. The last couple times I was out, I felt like the engine was almost bogging out a bit. I plan to change the plugs (haven't yet). Since my case can was empty, I filled up with premium 93, I figured I could use the extra detergent the premium provides. Well anyways.... I filled up with the premium 93, and the day I rode with it, I felt like it was running stronger.

In general I agree that if you car calls for 87 octane, then you won't gain anything, but drain you pocket by using higher octane. Every car I've owned for the past 15 years requires premium fuel, so I'm kinda using to paying for it anyways. I don't mind paying the extra couple bucks when I fill up my ATV gas can for the premium if it makes my Sportsman run better (even if it is in my head).

To each his own, I guess.