Improving performance with alcohol-free gas

jaguar

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#1
Reasons not to use gas containing alcohol (ethanol)
1)
alcohol has less energy to burn per same volume as gasoline. So the jets have to be larger when using ethanol (gas with alcohol) but still an engine using pure gasoline is more powerful. (3% larger jets with E10)
2) alcohol dries out rubber (crank seals, float valve tip on good carburetors, fuel line). A dried out crank seal will leak and need replacement. I unknowingly used 25% ethanol gas (because it’s unmarked) in my Suzuki 100 (brand new) and had to replace the seals after only 2 years.
3) alcohol removes some of the oil from the cylinder which lessens ring protection (so you have to use more oil for normal protection)

More than 98% of U.S. gasoline contains ethanol, typically E10 (10% ethanol, 90% gasoline), to oxygenate the fuel and reduce air pollution. E10 gas is available in all octane grades, including regular-87 and premium-91. Low-octane gasoline is blended with 10% ethanol to attain the standard 87 octane. Ethanol contains less energy per gallon than gasoline, to varying degrees, depending on the volume percentage of ethanol in the blend. Denatured ethanol (98% ethanol) contains about 30% less energy than gasoline per gallon. The higher the ethanol content, the higher the octane. 100% ethanol has an octane rating of 113. Ethanol fuels expire in 90 days. When exposed to excessive water they may expire even sooner. Studies have shown that after only 100 days, alcohol fuels absorb enough moisture to phase separate (separation of alcohol and gasoline).

The gas pumps should show the E rating (E10, E15, E85). If no alcohol-free gasoline is available then you can do this to take out the alcohol:
1. put the gasohol in a gas container
2. add 25% water and shake the container for mixture of water with alcohol (they attach to each other)
3. let the container rest for 30 seconds for the water/alcohol to settle to the bottom
4. slowly invert the container and loosen the cap so the water/alcohol comes out (hopefully into another container which you can empty onto concrete or asphalt outside for the alcohol to evaporate). Water/alcohol will be mostly clear but the gasoline will be colored so you can see the separation line.
5. turn the container upright, let it sit 10 seconds, pour its contents into the fuel tank or another container but leave the last couple of tablespoons of fuel in it because it will have a little bit of water/alcohol.

Go here to find a gas station that sells ethanol-free gas: https://www.pure-gas.org/

compression ratio - octane needed - cranking psi per compression ratio (with good rings)
5:1 - 72 - 79
6:1 - 81 - 109
7:1 - 87 - 137
8:1 - 92 - 164
9:1 - 96 - 189
10:1 - 100 - 213
11:1 - 104 - 236
12:1 - 108 - 257
 
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jaguar

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#2
If you haven't done the measurement-calculation to know your engines compression ratio then you can go by the cranking pressure but that has its drawbacks since pressure depends on ring end gap and how well your head gasket is sealing. If you are looking to buy a compression tester you need to know that most of them cause a lower psi reading for small engines because the part that threads into the spark plug hole is usually shorter than the part of the spark plug that screws in there. This leaves additional space which lowers the compression ratio. Looking on Amazon I found this gauge that isn't expensive and whose threads are longer than normal: https://www.amazon.com/gp/product/B000EVU89I/ref=ask_ql_qh_dp_hza
 

Joined
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#3
Reasons not to use gas containing alcohol (ethanol)
1)
alcohol has less energy to burn per same volume as gasoline. So the jets have to be larger when using ethanol (gas with alcohol) but still an engine using pure gasoline is more powerful. (3% larger jets with E10)
2) alcohol dries out rubber (crank seals, float valve tip on good carburetors, fuel line). A dried out crank seal will leak and need replacement. I unknowingly used 25% ethanol gas (because it’s unmarked) in my Suzuki 100 (brand new) and had to replace the seals after only 2 years.
3) alcohol removes some of the oil from the cylinder which lessens ring protection (so you have to use more oil for normal protection)

More than 98% of U.S. gasoline contains ethanol, typically E10 (10% ethanol, 90% gasoline), to oxygenate the fuel and reduce air pollution. E10 gas is available in all octane grades, including regular-87 and premium-91. Low-octane gasoline is blended with 10% ethanol to attain the standard 87 octane. Ethanol contains less energy per gallon than gasoline, to varying degrees, depending on the volume percentage of ethanol in the blend. Denatured ethanol (98% ethanol) contains about 30% less energy than gasoline per gallon. The higher the ethanol content, the higher the octane. 100% ethanol has an octane rating of 113. Ethanol fuels expire in 90 days. When exposed to excessive water they may expire even sooner. Studies have shown that after only 100 days, alcohol fuels absorb enough moisture to phase separate (separation of alcohol and gasoline).

The gas pumps should show the E rating (E10, E15, E85). If no alcohol-free gasoline is available then you can do this to take out the alcohol:
1. put the gasohol in a gas container
2. add 25% water and shake the container for mixture of water with alcohol (they attach to each other)
3. let the container rest for 30 seconds for the water/alcohol to settle to the bottom
4. slowly invert the container and loosen the cap so the water/alcohol comes out (hopefully into another container which you can empty onto concrete or asphalt outside for the alcohol to evaporate). Water/alcohol will be mostly clear but the gasoline will be colored so you can see the separation line.
5. turn the container upright, let it sit 10 seconds, pour its contents into the fuel tank or another container but leave the last couple of tablespoons of fuel in it because it will have a little bit of water/alcohol.

Go here to find a gas station that sells ethanol-free gas: https://www.pure-gas.org/

compression ratio - octane needed - cranking psi per compression ratio (with good rings)
5:1 - 72 - 79
6:1 - 81 - 109
7:1 - 87 - 137
8:1 - 92 - 164
9:1 - 96 - 189
10:1 - 100 - 213
11:1 - 104 - 236
12:1 - 108 - 257
I really don't think this is a good idea, intentionally mixing E10 gasoline with water will maybe separate some if not most of the alcohol out of the fuel, but you're left with a much lower grade of gasoline that is going to make your engine run much worse, and has the strong potential to leave water in the fuel you just 'treated'. This is a gamble on your engine's longetivity that's worse than if you just purchased non-ethanol 93 to start with.

And can you guarantee that the gasoline that remains isn't also compromised with residual moisture that will definitely cause corrosion on the inside of your 2 stroke engines?

I'd rather have the peace of mind knowing the $4.50~$5 a gallon non ethanol I normally buy will not harm my engine in any way. I've run all my small engines on non-ethanol for over 6 years now, and I've had no carburetor or engine issues due to fuel moisture or alcohol damage to the pumper carb's diaphrams or other butyl rubber bits

I'm not willing to try this, is the OP willing to try this on his best engine?
 

jaguar

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#4
I've been doing this for the last 6 months and I assure you all your fears are unfounded.
Water immediately goes to the bottom of the container because it is heavier than gasoline. So as long as you are careful to only pour out the gasoline then you are OK.
Without the alcohol the engine runs stronger and the seals will last much longer.
But I agree with you that if non-alcohol fuel is available then you should just buy it.
I do this because the only station with non-alcohol fuel is too far from where I live.
 


jaguar

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#6
Surprisingly that is actually a vast subject. Everyone else speaks in generalities on this topic but not me.
The #1 purpose of oil is to insure the longevity of your engine. Yes the piston/rings/cylinder are cheap but who in their right mind likes to split cases to replace the lower con rod bearing and crank bearings?
so to read my "opinion" please go to www.dragonfly75.com/motorbike/oil.html
 

RIZ

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May 14, 2018
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#7
Surprisingly that is actually a vast subject. Everyone else speaks in generalities on this topic but not me.
The #1 purpose of oil is to insure the longevity of your engine. Yes the piston/rings/cylinder are cheap but who in their right mind likes to split cases to replace the lower con rod bearing and crank bearings?
so to read my "opinion" please go to www.dragonfly75.com/motorbike/oil.html
I'll do that. Thanks.
 


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