Ethanol and Torque?

[SVOboy]

Was reading this: http://www.dartmouth.edu/~dfr/fall05_newsletter.pdf

They say that the turbo and the switch to e85 increases torque 20%, wtf is this I'm hearing about e85 and torque? Is it just the octane advantage or is it something else?

[omgwtfbyobbq]

The turbo's actually what's responsible for the large increase, since I doubt they can run 105 octane lean enough to increase torque by 20% with stock air flow. The E85 helps of course, but if the engine was run with gas and a turbo, there would be a much more significant increase in torque (provided fueling was available) compared to the modest increase by being able to advance timing and run a bit leaner on E85. Course I'm not exactly sure how much greater than stoich you can run with higher octane fuels, so i could be totally wrong.

[GasSavers_DaX]

It's probably like saying "Adding the JATO and a slightly larger crank sprocket to my bicycle allowed me to attain a MUCH higher top speed."

Both are contributing factors, but one greatly overshadows the other.

[Sludgy]

Ethanol does have a higher octane than gas, but the biggest reason for more torque and power is its heat of vaporization, which is higher than gas.

It takes more heat to vaporize a stoichiometric amount of ethanol than gas. Thus, the incoming air gets cooler. Cold air is more dense, meaning that a greater mass of air is drawn into the cylinders and thus more fuel can be burned. This increases the torque.

[SVOboy]

Hmm, very interesting stuff. I'm going to have to learn something about cars before I go bugging those damn engineers, currently I know very little, *cry*