Thread: What Octane Is and Does.

Vadim, it's a spammer, that's just a quote from Coheeds original post. Am I the only one who can see through these spammers?

Wow I can't believe I fell for that one . I don't think he had a spam link before though.

Either way I think my information was useful

Lower fuel mileage with E85 is due to the fact that E85 has less energy by volume than gasoline. You need more of it to make the same power as gasoline. About 25% more of it. This results in usually a 25% loss of fuel mileage.

Yes, but although you use more fuel you can also get more bang from it as well. A little off topic, but since you are adding more fuel because E85 carries its own oxygen with it, you get more fuel in the cylinder as well. Tuners have made more power from this effect.

Sorta like Nitromethane. 4:1 stoich ratio with less BTU/gallon than gasoline, but you can add 4x the fuel to get the correct mixture and make a lot more power.

Gasoline does have a cooling effect as it evaporates, but the enthalpy of transformation for gas is a lot less than water. Its effect isn't very pronounced unless in large quantity. But having a richer mixture does prevent having lean spots in the chamber which can cause detonation. If a motor were designed and was 100% efficient on getting the mixture perfectly mixed, then you could technically run at a higher AFR without having any issues. But the mixing efficiency of the combustion chamber is far from 100%. Since every combustion chamber is different for each configuration of motor, different designs can run slightly different ratios.

The MON for most E85 fuels is about 100-105. They have the tendency of performing like a unleaded race gas. They are more forgiving when the mixture is a little too rich though, and power drops off less in a rich condition when compared to gasoline. But it, like gas, hates to run lean. It has been said that running lean on E85 is worse than running lean on gasoline, though I wouldn't suggest experimenting to see which one is better under those conditions

E85 is very interresting, the gains are in the race-gas-area and the next gas-station for E85 is 15miles away from my house. But, all the fuel-guiding parts on the car have to be E85-resistant, and most stock parts are not.

this is a lot of good info.. got a headace from reading it all lol