Hey retro-rocket, I also was wondering about the premium grades, do you mean grades of 89 or higher or 92 and higher, anyway, let us know!!!

 

pastor: To have the piston/rings go out in a year would depend on the miles driven,it is possible,but doubtfull.
Yes the valves may need adjustment after a year. This is what I'm leaning toward as the problem [img]i/expressions/face-icon-small-happy.gif[/img]

 

just what i hear but "race gas" will go bad extreemly quik it absorbes water or something? just what i hear

 

I run 115 octane in my dodge.

 

I have a friend who owns a gas station, it has been in his family for a very long time, he is the one who told me that a stabilizer is added to the"premium" blends. That is ONE of the reasons that premium grades cost more. Keep in mind that the stabilizer is not the same strength or quality as the stuff that you buy and add to gasoline yourself, But it wil stay "fresh" longer than standard grade stuff. Also keep in mind that gasoline stored in plastic containers (like most gas cans and atv fuel tanks) does not keep as well as that stored in metal containers. Race fuel is stored in metal drums, and the manufacturer of that fuel will recomend that you keep it tightly sealed when not in use to preserve it.
Before anyone jumps to the next logical conclusion, which is that my friend told me this so that he can sell more expensive fuel, that is not the case. The amount of fuel he sells for small engines would be less than 1% of his sales so he's not going to get rich by telling anyone this.

 

Forgot one part, on what octane they start putting in stabilizer, he said "all premium grades" where i live we do not have straight 89 octane. We have 87, 89, and 92 available, but in my area the middle octane ( I think it's 89) contains a percentage of alcohol so i don't mess with it due to jetting and condensation issues in the cold weather here. I never thought to ask him what "premium" meant, it might be different for other areas. I use 92 for my snowmobiles, atvs, chainsaws ect. I also use it in my streetbike because it has 4 carbs on it and i really do not want to go through all 4 of those carbs again to clean out the green crap you get in them from old fuel. For me, the cost over the year is slightly higher over a year, but i don't end up with fuel quality issues. I DO NOT use higher grades in my automobiles. GT2- i hear ya on that one, i think the reason you won't hear about it is that the fuel companies would have to admit that the crap they are selling us and calling fuel is junk. I think that there is a reason why we are paying about the same for gas today as we were in 1984, it is lower quality, just like the stuff we were buying in 1984 was lower quality than what we (not me, i'm not THAT old) were buying in 1970.

 

Here is the scoop.

First off, octane is resistance to detonation. Antinknock index. Yes the higher the octane in a machine that requires less octane makes less power. BUT, the advantage to higher octane is you can run a higher compression RATIO.. Doing a compression test isnt going to tell you how much octane you can use..

If you do motor mods, ie advance the timing you would have to run premium. This is the only reason to run premium. There is no stabil in premium fuels, they last no longer. All fuels have additives already (just like the stuff you buy off the shelf) The only company that I know of is chevron that has different premium. They put larger amounts of Techron in their premium.

So in short, unless you are advancing the timing, run the least octane you can before pinging. I dont believe there is a stock atv out there with 12.1 :1 compression ratios....

 

First off, i never said there was stabil (which is a brand name) in pump gasoline or any other fuel. I said there was a fuel stabilizer added. Yes, there are additives in all gasoline, just like there is in all modern oils. I got the fuel information from someone that i consider a reliable source. I have also had low grade fuel go bad faster than premium grade, which fits in line with the information i was given. I have also had the local chainsaw dealer tell me to run premium gas if it might be in storage for a while. 1 month seems to be the point that i keep hearing. I could be wrong but i don't have any evidence to the contrary.

The need for higher octane fuels is based upon numerous factors, such as combustion chamber design, timing, combustion chamber temperature, and cylinder pressure, of which compression ratio is only a part of. An engine with a high static compression ratio, but has a long duration cam, may be able to run a lower octane fuel and not have detonation. Similarly, you can advance the timing in some engines without detonation or the need to go to a higher octane fuel. Tuning needs to be done to determine this, there is no magic number, just guidelines. Moded machines that have high cylinder presuure need to have an experienced tuner to figure out what you can get away with in terms of fuel. The manufacturers recomendation is still a good bet for stock machines to go on because they are not going to recomend a fuel that is going to cause warranty problems. I choose to go with a gasoline that will probably result in slightly less performance, but which doesn't break down as quickly. The choice is up to the individual, but like grizz says, the primary reason is that you are trying to avoid detonation, which should not be happening in a properly tuned stock machine.