100 octane

[atv]

I have a fuel tank and electric pump in my barn. I buy gas 100 gallons at a time. I use this gas for lawnmowers, trimmers, four wheelers, chain saws, and of course, my sled. It takes me over two years to use this much gas.

These days, gas does not seem to last two years before it goes bad. So, I mix in about 30% 100LL aviation fuel, which seems to have a half life of 100 years.

When storing my motorcycle and sled for the off season, I fill the tanks with 100LL. My Titan motorcycle has a high compression S&S engine and needs premium gas. It really likes 100 octane fuel. It starts in the spring like I ran it yesterday.

My sleds have always run really good on it, also. My '06 RTX seems to like it real well. Every year, the first tank of fuel I run thru it is the 100LL aviation fuel that I stored it with the previous spring.

I can't say the perfomance is in any way diminished, in fact it seems like it runs better than with 87 oct pump gas. But, from what I've read, it shouldn't run as well.

So, you guys who know more than me, what do you think?

 

[LazyBastard]

One of two things;
1) You're imagining things as it WILL NOT run as well on 100.
2) because it sits for so long, the real number may be closer to 87 (or even lower) than you think.

 

[bashley]

You would have to do alot of searching but I do remember reading about dyno reports showing higher octane fuels running the same if not worse than 87.

The reason is, longer stroked, high compression engines need higher octane because it has a longer burn cycle, burns more complete. Lower octane (87) actually has a higher combustion (explosive) factor but is a shorter lived burn. Perfect for lower compression, shorter stroked motors.

As far as your fuel tank goes, if you want the gas to store longer you'll have to add some Sta-Bil or something similar. Gasoline in the lower 48 and Canada is made by molecular reconstruction of kerosene, and after time it tries to revert back to it's natural state. The Av/Gas you put in there is made a little differently and has more natural product than regular unleaded keeping it stable longer. I've never used these products so I can't tell you how your machines will run with it

 

[Jesster]

100 aviation gas is different than 100 automotive, too. They use a different rating scale.

 

[atv]

100 aviation gas is different than 100 automotive, too. They use a different rating scale.

Well, that makes some sense to me. Along the same lines, small planes that can use 80 oct aviation fuel (which you can't get anymore) get along nicely on 87 oct car gas.

I know many FBO (Fixed Base Operators) add 10% 100LL to their car gas tanks to keep it from going bad.

 

[black john]

100ll

100 LL has a rather high lead content thus it stays closer to 100. it is made for higher compesion moters. we ran 100/115 av gas in ower srx 340/440 s as per yamaha s recomended. how ever i never had moter cycle or truck run well on the left over gas in the spring. and those poor little briggs moters on ower lawn mowers never made a full seson of grass cutting before the valves burnt. the only othe moter i had that ran well on this was my full mod kawasaki 750 (h2) and at 60 miles to a tank of fuel it was some hard to keep runing. but what a fun 60 miles. but back in those days pretty well every ones sleds on the ice ovals ran 100/130 . merc twisters Z cats yamaha s you mane it as it was what was recomended right in the owners manual as the fuel to run and there was quit a jeting change if you wanted to run any thing other than this as the fuel was less dense than other fuel ie lighter gravity .

 

[atv]

I have never had a problem running 100LL in any engine. However, because it is leaded gas, running it in anything with a cat converter would not be good. 100LL has about 4 times the lead in it as leaded car gas used to have.

My old car buff friends tell me that valve seats in antique cars have to be changed in order to run today's unleaded fuel.