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Old 12-06-2017, 02:20 PM   #1
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Ethanol free gas?

Iíve heard this is cleaner and a bit more power, but itís 88 octane.

Good or bad for P car?
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Old 12-06-2017, 02:46 PM   #2
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Ethanol free is good particularly during storage as there is water in ethanol fuel. I use 91 EFree in my Audi (turbo) and feel an increase in power though theoretically the power and acceleration is same as Ethanol.
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Old 12-06-2017, 03:26 PM   #3
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Originally Posted by Timco View Post
I’ve heard this is cleaner and a bit more power, but it’s 88 octane.

Good or bad for P car?
Not good in either situation. Ethanol is an oxygenator in fuel and is why it is a much cleaner fuel. While ethanol is less energy dense with less power per gallon, the 91 octane will absolutely outperform the 88 octane non-ethanol fuel. 91 octane will allow significantly more ignition advance where the 88 will most likely knock with resulting ignition retard making less power. I believe 93 octane is the min recommended octane but 91 is typically all you can get. I have been mixing 3 gallons 100 octane and 11 gals 91 to get 93 to 94 octane.
As far as water in fuel.......Ethanol fuel has the ability to absorb water which may be desirable during storage since the ethanol can carry water through the system. Water will separate out and form free water in ethanol free fuel and is why it is recommended to have a full tank when using ethanol free fuel during storage, this is to minimize exposed surface area of the tank that can condense water. Pick your poison.

Last edited by 911monty; 12-06-2017 at 03:53 PM.
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Old 12-06-2017, 03:44 PM   #4
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Or you can use StaBil in fuel with up to 10% EToH for storage, and it will prevent any issues. Over 10%, use their marine grade stabilizer.
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Old 12-06-2017, 04:27 PM   #5
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For daily use, definitely the higher octane w/ ethanol. For long storage, the ethanol free. I never really bought into the "fears" of keeping the ethanol fuels over time, but I was wrong. In as short as 1 year, they can begin to gel and cause all sorts of problems. Thankfully I didn't discover this in my Boxster, but in a pressure washer....totally gummed up the carb, which resulted in having to disassemble and clean. Learned my lesson...for any item I use infrequently or store, I keep ethanol free fuel around, don't even mess with adding stabilizers.
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Old 12-06-2017, 04:47 PM   #6
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For daily use, definitely the higher octane w/ ethanol. For long storage, the ethanol free. I never really bought into the "fears" of keeping the ethanol fuels over time, but I was wrong. In as short as 1 year, they can begin to gel and cause all sorts of problems. Thankfully I didn't discover this in my Boxster, but in a pressure washer....totally gummed up the carb, which resulted in having to disassemble and clean. Learned my lesson...for any item I use infrequently or store, I keep ethanol free fuel around, don't even mess with adding stabilizers.
Fuel "gelling" is actually caused by evaporation of the volatile components of the fuel and leaving the heavy "varnish" behind. This varnish is what plugs jets and coats the floats in a carbureted system. This will happen with free or ethanol fuel. Best practice is to run carb dry or drain for storage and use Stabil to minimize varnish formation.

Carburetors are prone to this issue since they are a vented atmospheric system, this allows the volatile components aka "light ends" to freely release to the atmosphere until everything in the carburetor evaporates and dries out. Gasoline in an EFI system is enclosed and does not vent to the atmosphere. Since the system is closed the volatile components will vaporize only until the Reid Vapor Pressure (RVP) of the fuel is attained. This is the point where vapor pressure is in equilibrium and the light ends no longer vaporize but remain in solution. This pressure is the pressure you release when you remove the gas cap. There is a standard RVP for fuel and it is typically ~7-9 psi. Just FYI.

Last edited by 911monty; 12-06-2017 at 09:40 PM.
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Old 12-07-2017, 05:33 AM   #7
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fuel

Fuel availability seems to vary area by area. I have nine motorcycles (all with carbs) and stay away from the ethanol. It turns some carb floats heavy over time and turns many of the rubber parts hard. The only fuel we can get in our area (Minnesota) without ethanol is 91 octane. It works great in my 986S and my high performance bikes. I have four older BMW motorcycles that don't require the high octane and I still have to buy the high dollar premium fuel to get it ethanol free. If I cross the border into Iowa I can get 87 octane ethanol free at a much cheaper price. I wish we had it available here in Minnesota and Wisconsin.
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Old 12-07-2017, 06:52 AM   #8
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Quote:
Originally Posted by Twin headlight Ernie View Post
I have nine motorcycles (all with carbs) and stay away from the ethanol.
Hello Ernie, by having nine bikes must be difficult to choose which one to ride, even if you ride a different bike every day...
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Old 12-07-2017, 07:40 AM   #9
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bikes

My bikes are a pretty wide variety. Dirt bike to full dress road. I do rotate the street bikes for commuting. It's a bit of a pain to keep them all fresh gassed and running good.
Bikes tend to run better the more they get used. Same with the 986S. My winter car is a Subaru that doesn't seem to mind sitting near as much as everything else I own. lol
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