100 octane
Cruiser
Joined: Nov 2007
Posts: 156
Likes: 2
From: Here and there.
RE: 100 octane
100 octane is a waste of money if the engine isn't designed to run on it. What's been said regarding burn time (higher octane = slower) is all correct.
Running too high of octane in an engine not designed for it is not oly a waste, but in some cases can create a rich running condition and or leave unnecessary deposits.
If a vehicle is designed for 92, running 94 is OK or if there are a few mods involved. Running 100 in a vehicle designed for 89-91, is just throwing money away, IMHO.
Dyno testing of some vehicles has actually shown a drop in HPs by running octane fuel too high for that engine. My former race bike was one of them. Made the most HPs on 92, and nothing higher. U4 race fuel worked nicely and made extra HPs, but left nasty deposits in the venturis. Wasn't woth the cost.
Running too high of octane in an engine not designed for it is not oly a waste, but in some cases can create a rich running condition and or leave unnecessary deposits.
If a vehicle is designed for 92, running 94 is OK or if there are a few mods involved. Running 100 in a vehicle designed for 89-91, is just throwing money away, IMHO.
Dyno testing of some vehicles has actually shown a drop in HPs by running octane fuel too high for that engine. My former race bike was one of them. Made the most HPs on 92, and nothing higher. U4 race fuel worked nicely and made extra HPs, but left nasty deposits in the venturis. Wasn't woth the cost.
Road Captain
Joined: Jul 2007
Posts: 682
Likes: 1
From: Wichita, KS
RE: 100 octane
100LL isn't exactly low lead. At a maximum of 2 grams/gallon, itis considerably higherin lead content than what regular leaded fuel was back in the day. 100LL does a great job of lubricating things, especially in a high temp, high compression engine. But, it also does a great job of fouling plugs, and valves if you have a low compression engine. You can run Alcor to combat the lead deposits tho.100LL will also turn your exhaust tips a nice grey color, and make your engine oil blacker than the ace of spades in a very short time.
At $4+/gallon, it's not cheap either. Now, one other thing you can do is to mix 100LL with say regular unleaded. It will burn a little hotter, which will help prevent the lead from sticking to things, and instead be blown out the exhaust. But, if it was an octane boost you were looking for to begin with, it's now been negated.
One last thing to consider. Depending on the local leo's in your area, theCleanAir Actbanned the sale of leaded fuel for use in on-road vehicles. Possession and use of leaded gasoline in a regular on-road vehicle now carries a maximum $10,000 fine in the United States. If they really wanted to stick it to you, they certainly could.
At $4+/gallon, it's not cheap either. Now, one other thing you can do is to mix 100LL with say regular unleaded. It will burn a little hotter, which will help prevent the lead from sticking to things, and instead be blown out the exhaust. But, if it was an octane boost you were looking for to begin with, it's now been negated.
One last thing to consider. Depending on the local leo's in your area, theCleanAir Actbanned the sale of leaded fuel for use in on-road vehicles. Possession and use of leaded gasoline in a regular on-road vehicle now carries a maximum $10,000 fine in the United States. If they really wanted to stick it to you, they certainly could.
Road Captain
Joined: Apr 2007
Posts: 583
Likes: 2
From: KC
RE: 100 octane
Continental and Lycoming engines seem to like it. I agree with everyone else, though, wouldn't waste the time or money putting it in my bike. The only fuel these engines need can be bought at your local station.
Outstanding HDF Member
Joined: Dec 2007
Posts: 2,215
Likes: 2
From: Northern Arizona
RE: 100 octane
I was raised a methodist, I don't believe in predetonation, will the higher octane be okay for me? Sorry - couldn't resist.[8D]
ORIGINAL: cigarman
I have had over 30 cars in my life and currently have a Corvette in addition to my Street Bob as my toys.
I am also active on a variety of forums and without a doubt ocatane is brought up and posts are made as to the value of high octane fuel and how performance is enhanced in every forum. This is all based on a misunderstanding of what octane means. High octane fuels are not more powerful, they are more resistant to compression detonation in opoosition to the ability to burn more easily (referred to as combustion).
Fuels with higher octane ratings "explode" less easily--in higher compression engines they do not tend to predetonation when the compression increases. Lower octane rating fuels will explode more easily and so are more suited to lower compression engines.
The best fuel to use in any particular engine is the octane at which the engine runs without predetonation. Using an octane rating that is higher than necessary provides no advantage in terms of power; this has been proven time and time again with dyno testing.
However using an octane rating lower than optimum will result in predetonation (knock) and can damage the engine.
You can "tune" and modify engines to prevent the knock and also to gain minor performance gains from higher octane fuels, but in general it is an expensive and wasteful means to gain performance.
Some of this misunderstanding comes from the roots of high performance sports cars and motorcycles that have one version for racing and are essentially "detuned" for street use. People believe that the race vehicles simply are using higher octane and so put that in their engines to gain the racing performance.
Use the fuel that you are most comfortable with, but the likelihood is that the motors you refer to would run just as efficiently (and definitely more cheaply) with a fuel of lower octane rating.
I have had over 30 cars in my life and currently have a Corvette in addition to my Street Bob as my toys.
I am also active on a variety of forums and without a doubt ocatane is brought up and posts are made as to the value of high octane fuel and how performance is enhanced in every forum. This is all based on a misunderstanding of what octane means. High octane fuels are not more powerful, they are more resistant to compression detonation in opoosition to the ability to burn more easily (referred to as combustion).
Fuels with higher octane ratings "explode" less easily--in higher compression engines they do not tend to predetonation when the compression increases. Lower octane rating fuels will explode more easily and so are more suited to lower compression engines.
The best fuel to use in any particular engine is the octane at which the engine runs without predetonation. Using an octane rating that is higher than necessary provides no advantage in terms of power; this has been proven time and time again with dyno testing.
However using an octane rating lower than optimum will result in predetonation (knock) and can damage the engine.
You can "tune" and modify engines to prevent the knock and also to gain minor performance gains from higher octane fuels, but in general it is an expensive and wasteful means to gain performance.
Some of this misunderstanding comes from the roots of high performance sports cars and motorcycles that have one version for racing and are essentially "detuned" for street use. People believe that the race vehicles simply are using higher octane and so put that in their engines to gain the racing performance.
Use the fuel that you are most comfortable with, but the likelihood is that the motors you refer to would run just as efficiently (and definitely more cheaply) with a fuel of lower octane rating.
Road Warrior
Joined: Dec 2007
Posts: 1,437
Likes: 0
From:
RE: 100 octane
ORIGINAL: speedjunkie
100LL isn't exactly low lead. At a maximum of 2 grams/gallon, itis considerably higherin lead content than what regular leaded fuel was back in the day. 100LL does a great job of lubricating things, especially in a high temp, high compression engine. But, it also does a great job of fouling plugs, and valves if you have a low compression engine. You can run Alcor to combat the lead deposits tho.100LL will also turn your exhaust tips a nice grey color, and make your engine oil blacker than the ace of spades in a very short time.
At $4+/gallon, it's not cheap either. Now, one other thing you can do is to mix 100LL with say regular unleaded. It will burn a little hotter, which will help prevent the lead from sticking to things, and instead be blown out the exhaust. But, if it was an octane boost you were looking for to begin with, it's now been negated.
One last thing to consider. Depending on the local leo's in your area, theCleanAir Actbanned the sale of leaded fuel for use in on-road vehicles. Possession and use of leaded gasoline in a regular on-road vehicle now carries a maximum $10,000 fine in the United States. If they really wanted to stick it to you, they certainly could.
100LL isn't exactly low lead. At a maximum of 2 grams/gallon, itis considerably higherin lead content than what regular leaded fuel was back in the day. 100LL does a great job of lubricating things, especially in a high temp, high compression engine. But, it also does a great job of fouling plugs, and valves if you have a low compression engine. You can run Alcor to combat the lead deposits tho.100LL will also turn your exhaust tips a nice grey color, and make your engine oil blacker than the ace of spades in a very short time.
At $4+/gallon, it's not cheap either. Now, one other thing you can do is to mix 100LL with say regular unleaded. It will burn a little hotter, which will help prevent the lead from sticking to things, and instead be blown out the exhaust. But, if it was an octane boost you were looking for to begin with, it's now been negated.
One last thing to consider. Depending on the local leo's in your area, theCleanAir Actbanned the sale of leaded fuel for use in on-road vehicles. Possession and use of leaded gasoline in a regular on-road vehicle now carries a maximum $10,000 fine in the United States. If they really wanted to stick it to you, they certainly could.
There are addictives you can put into gas to make it comply with the specification of older, leaded gas and avoid undue valve seat wear.
Road Captain
Joined: Aug 2007
Posts: 642
Likes: 1
From: Baton Rouge, Louisiana
RE: 100 octane
ORIGINAL: railbird
I'm no expert, so I won't say to definately take my advice, but I have always heard to use the recommended octane for your motor and as long as it isn't knocking, using anything more would be a waste of money and contribute to more carbon build-up.
I'm no expert, so I won't say to definately take my advice, but I have always heard to use the recommended octane for your motor and as long as it isn't knocking, using anything more would be a waste of money and contribute to more carbon build-up.
What he said .....
Cruiser
Joined: Sep 2006
Posts: 121
Likes: 0
From: Hershey, PA
RE: 100 octane
I did not think about this when I made my initial post but thought about the LL designation later. Be aware that lead, even in small quantities, coats the platinum in catalytic converters and renders them permanently damaged. It does the same with O2 sensors, so using 100LL in any newer engine will cost you $$$ in repairs.
The 40 year old engines likely do not have 02 sensors or cats and so would not have that cumulative effect.
The 40 year old engines likely do not have 02 sensors or cats and so would not have that cumulative effect.
Advanced
Joined: Feb 2006
Posts: 93
Likes: 0
From: Southeastern Idaho
RE: 100 octane
For anyone that wants to know you can get cool blue 100 octane unleaded......run it in the dirt bikes and the sleds.....won't screw up the 02 sensor if you want to run it in the HD.....highest pump gas around here is 91 so we mix to get up arount 95-96......just FYI
Tourer
Joined: Oct 2007
Posts: 439
Likes: 22
From: League City, Texas
RE: 100 octane
Remember not all gasoline is created equal. I have a relative who is a chemist for one of the plants(Shell) here on the Houston ship channel (for those not familiar, we have countless chemical plants in and around houston). Part of his job is testing gasoline for a living. He tests Shell's gas against the other brands on the market. He told me (remember this is what i was told) that the gas that tested the cleanest and was consistantly closest to its advertised octane was Chevron. He basically said Chevron 89 is better than most brands 93. Just thought I'd pass that along.
Road Master
Joined: Nov 2007
Posts: 897
Likes: 0
From:
RE: 100 octane
ORIGINAL: dklozik
Remember not all gasoline is created equal. I have a relative who is a chemist for one of the plants(Shell) here on the Houston ship channel (for those not familiar, we have countless chemical plants in and around houston). Part of his job is testing gasoline for a living. He tests Shell's gas against the other brands on the market. He told me (remember this is what i was told) that the gas that tested the cleanest and was consistantly closest to its advertised octane was Chevron. He basically said Chevron 89 is better than most brands 93. Just thought I'd pass that along.
Remember not all gasoline is created equal. I have a relative who is a chemist for one of the plants(Shell) here on the Houston ship channel (for those not familiar, we have countless chemical plants in and around houston). Part of his job is testing gasoline for a living. He tests Shell's gas against the other brands on the market. He told me (remember this is what i was told) that the gas that tested the cleanest and was consistantly closest to its advertised octane was Chevron. He basically said Chevron 89 is better than most brands 93. Just thought I'd pass that along.
I have heard the same info from a few folks in the auto industry. too bad that those Chevron stations are far and few between in Illinois.
Used to live out west and only used Chevron. There is a Shell station Nearby that sells preimum 93oct. Not the 91 that is common at most stations.