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Higest Compression With E-85 Fuel ?
With aluminum heads what is safe using E-85 ?
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13 to 1
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Is there different grades on E-85 ?
More and less percent of oxygen ? |
E85 is E85 (85% methanol), no different grades. It has roughly 75% the energy of gas so you need more of it, roughly 25% more for the same power as 100% gasoline. It has a much higher octane rating than straight gasoline. T
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85% ethanol, not methanol. Too different fuels.
Ethanol is grain alcohol. Methanol is wood alcohol. Methanol is also toxic. |
Just looked and Lincoln has 35 gas stations that have the fuel and Omaha even more, so no problem finding E-85.
I did not know that Methanol is wood,...alcohol. |
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If you're planning on using pump fuel, you can bump your dynamic compression up a bit, but don't go crazy. There's a lot of variability from pump to pump, and at different times of year. E85 may be anything from e80 to e90'ish.
The other issue is that they use some pretty cheap gasoline for the other 15%. It's really low octane unleaded stuff from the bottom of the tank. It can get up under the first ring land and detonate. It looks like a scene from "Alien". If Photobucket still worked, I'd show you a picture of that. If you really want to go racing with high cylinder pressures, you'll need to use real e-85 race fuel. Otherwise, keep dynamic compression below about 8.5-9.0ish. |
In Canada, the United States, Brazil, and some other countries, the octane number you'll see at the pump is the average of the RON and the MON numbers used elsewhere. It's called the Anti-Knock Index (AKI), and it's often posted on pumps as (R+M)/2. That's the number you need to know. The actual percentage of ethanol to gasoline isn't relevant. You just want to know how resistant the final fuel blend is to detonation. 112 (racing gas) is better than 102. 102 (lesser quality racing gas) is better than 92 pump gas, and so on.
The percentage of ethanol to gasoline is important when it comes to your air-fuel ratio. Ethanol contains less chemical energy than does gasoline, so a "gasohol blend" will tend to run lean (hotter in the combustion chamber). It's possible to lean out your fuel mixture and burn a head gasket or a piston without detonating the engine when using E-85. |
I know of a few engines locally that are around 14:1 compression.
These are big cubes big blocks with large solid roller cams which would bleed off a bit of cylinder pressure. |
Gotta watch about E-85. Yes, you can run more compression, but you also need special fuel system components. It requires a lot more flow and you need a lot more of it to make power, as compared to pump gas or race fuel.
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Most of the pumps now have a disclaimer stating that actual alcohol level in E85 is somewhere between 50% to 85%. So if you want to go down this path, plan on 50% alcohol for compression, and 85% alcohol for consumption unless your vehicle has a way of detecting alcohol content like a new Flexfuel car.
Guys on the LS board are running E85 with 11:1 compression and 10 pounds of boost on twin turbos. 1400 horsepower is not out of the question. |
The 50% - 85% is what I found when I looked at. 85% is just too hard to light to start a cold engine when it is below 0 F. They have to add more gasoline in the winter, and gasoline is usually cheaper, so you never know what the true blend is going to be from one tank to the next.
Some of the EFI tuning crowd have tried running E85 with the A9L box code ECU - which was 1989-1993 Mustang GT 5.0 manual. They have issues going lean and rich from tank to tank. I expect a Carb would be similar problems, but I do not know if the fuel molecule size differences would tend to help or make the issue worse. I think gasoline molecules are smaller and more would flow through a jet than ethanol. If true, then when you had more gasoline in the mix it would run richer, which is exactly the opposite of what you need. Sounds like a carb would be less tolerant than EFI. If that wasn't the case, I would have switched to it myself. I decided to stay away based on others experience. |
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