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Avedis53... <thanks for posting this.
 

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I know just enough to be dangerous...so look out.
 

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That's right he is old and crafty, if your not careful he will trap you in a lecture about the relationship between the various chemical components for an hour. :)

Ah no but really I do love your posts, always feel like I'm learning something.
 

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no Eton gas

I know just enough to be dangerous...so look out.
Avedis53... Alcohol is anhydrous and absorbs water. That's why it's banned in aviation fuel. It reeks havoc in my small engines. Soooo I want a source of volume gasoline w/o etoh in it. The airport is close by and pumps fuel. But it's over 100 octane. It's also fairly expensive...

?? Will this hurt a lawnmower, leaf blower, lawn tractor chain saw, or outboard motor? I thought high octane just prevented detonation, a flame retardant of sorts. To much octane is a waste, but is it harmful?

The closest non alcohol place that pumps gas at under 100 octane (90 i think) is 2 hrs away. 4 five gallon tanks might be worth the trip. I also heard VT is considering banning gas that has alcohol in it since it's hurting the tourism industry (boating). If so I can't wait!
 

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Just to be clear, anhydrous means "contains no water". Ethanol is hydrophilic, which means it loves to absorb water, even out of the air.

If you buy just about any ethanol, it will contain some water as the azeotropic composition of an ethanol/water mixture is about 96% ethanol and 4% water. What that means is you can't get higher than 96% ethanol by simple distillation since the azeotropic composition boils at the same temperature as pure ethanol, so further separation by distillation can not continue.

There are other means besides simple distillation to get to 100% ethanol though. The addition of an entrainer or the use of a permeable membrane is necessary to separate that last bit of water out of the ethanol to make it anhydrous. Anhydrous ethanol must be kept sealed from air as it will readily absorb water vapor out of the atmosphere.

So much for the chemistry lesson of the day. To answer your question, burning 100 octane gas shouldn't hurt your small gas engine equipment. It is rather expensive to do that but so is driving 2 hours to get ethanol-free gas. Driving around with 20 gallons of gas in portable containers in your trunk could result in you getting home a lot faster as a burning projectile if you get rear-ended though.
 
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Avedis53... Alcohol is anhydrous and absorbs water. That's why it's banned in aviation fuel. It reeks havoc in my small engines. Soooo I want a source of volume gasoline w/o etoh in it. The airport is close by and pumps fuel. But it's over 100 octane. It's also fairly expensive...

?? Will this hurt a lawnmower, leaf blower, lawn tractor chain saw, or outboard motor? I thought high octane just prevented detonation, a flame retardant of sorts. To much octane is a waste, but is it harmful?

The closest non alcohol place that pumps gas at under 100 octane (90 i think) is 2 hrs away. 4 five gallon tanks might be worth the trip. I also heard VT is considering banning gas that has alcohol in it since it's hurting the tourism industry (boating). If so I can't wait!
If those small engine devices are 2 stroke do what I do. I have a Stihl blower and string trimmer. I use their "Moto Mix". It is a 99% alkylate fuel with a synthetic oil added at 50:1. It is 93 octane and has a shelf life of years. It eliminates the hassle of mixing and performs great. It is expensive at $7.00 per quart but those small engines consume so little it is worth it. Two quarts will last me all season with fuel left over. At the end of the season I just clean the tools up and put them away with whatever is left in the tank. They start on the first pull next spring. No hassles. No need to add Sta-Bil. Clean burning also. May extend the engine life of your devices.
 
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Avedis53.. hydrophilic... I like this one better -> hypergolic ? a+b=boom

Actually, I meant to say Etoh is "hygroscopic" sorry.

I'd pick the gas up in my pick-em-up truck using a ratchet strap under the handles. This has worked well for me in the past.
 

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Technically, we are both correct. A hygroscopic substance readily absorbs water out of the air, which is what pure ethanol will do. Ethanol is also hydrophilic in that it is infinitely soluble in water.
 

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Hey all - currently live in Denver, CO and can't find 93 anywhere in the state! I'm using all the websites available, reddit, etc. just nada! C'MON COLORADO! Anyone know any places? Thanks so much!
 

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If I recall correctly, the high altitude in most of Colorado makes 93 octane unnecessary.
Yes. For example, instead of 87 octane regular unleaded, in CO they sell 85 octane regular unleaded.
 
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Wouldn't you just offset less dense air with more boost and need the higher octane at that point? Obviously there is a limit, but at mid RPM say someone at sea level runs 16PSI boost, couldn't that be offset by running 18PSI (or whatever the math is) in a high altitude area?
 
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Wouldn't you just offset less dense air with more boost and need the higher octane at that point? Obviously there is a limit, but at mid RPM say someone at sea level runs 16PSI boost, couldn't that be offset by running 18PSI (or whatever the math is) in a high altitude area?
That's a great question! I agree with your logic for sure.
 

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100606


Going from sea level @ 21% O2 up to Denver, CO @ 5280 feet drops the O2 down to about 11%. So about half the oxygen is available. More boost would be required to achieve the same amount of oxygen charge to the engine.
 

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View attachment 100606

Going from sea level @ 21% O2 up to Denver, CO @ 5280 feet drops the O2 down to about 11%. So about half the oxygen is available. More boost would be required to achieve the same amount of oxygen charge to the engine.
Love it, thanks so much for the response and the graph. Cheers!
 

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Just be careful how fast your spinning the turbos! If you have a red-sport, the car will monitor spin speed for you. If not, you may run into an issue! Not sure the relationship of spin speed to PSI when air is 20% thinner. Seems these turbos have a max PSI around 20 or so at sea level, so they may not be capable of producing 18 PSI in Denver? MIND BOGGLING!!! Would be interesting to see all the math on it!
 
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Just be careful how fast your spinning the turbos! If you have a red-sport, the car will monitor spin speed for you. If not, you may run into an issue! Not sure the relationship of spin speed to PSI when air is 20% thinner. Seems these turbos have a max PSI around 20 or so at sea level, so they may not be capable of producing 18 PSI in Denver? MIND BOGGLING!!! Would be interesting to see all the math on it!
BorgWarner says a good rule of thumb is that the turbocharger impeller speed will increase 1%-2% for every 1000 feet of elevation gain.
 
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Just be careful how fast your spinning the turbos! If you have a red-sport, the car will monitor spin speed for you. If not, you may run into an issue! Not sure the relationship of spin speed to PSI when air is 20% thinner. Seems these turbos have a max PSI around 20 or so at sea level, so they may not be capable of producing 18 PSI in Denver? MIND BOGGLING!!! Would be interesting to see all the math on it!
Thanks JCB, I
Just be careful how fast your spinning the turbos! If you have a red-sport, the car will monitor spin speed for you. If not, you may run into an issue! Not sure the relationship of spin speed to PSI when air is 20% thinner. Seems these turbos have a max PSI around 20 or so at sea level, so they may not be capable of producing 18 PSI in Denver? MIND BOGGLING!!! Would be interesting to see all the math on it!
Thanks for the response, I totally agree. Finally getting the Q on a dyno in the upcoming weeks - crazy back log of customers waiting as well. I guess the pandemic created a lot of new gear heads! I'll share my results from my appointment and JB4 logs.
 
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