[mwebb]

from a current thread on IATn
basically
NERYS is correct

those that claim there is no difference in FE using E10 as opposed to using E0
are wrong .

now we can get all juvenile and start with name calling and nastiness or
accept what is real , facts is facts .

if you add oxygen to the fuel , there is less room for fuel , so more fuel will be needed to provide the same amount of GO .
KISS
E10 has oxygen added to the fuel .... nuff said

"At 08:07:02 PST on 10-19-10, Karl Damal wrote:

> I was reading HP and torque specs for a newer GM truck. It
>had appr 10% more power if using E-85 vs standard E-5 to
>E-10 gas. This goes against all arguments I've read on iATN.
>Do they take advantage of a more agressive spark advance
>curve,or what?

Hi Karl,

>IF this is true, I am also assuming more fuel
>is spent to achieve this extra power?

Yes.

You are correct that a few here on iATN probably have it
wrong; but you may be misinterpreting some of the statements
about ethanol fuel economy too.

Here you are talking about horsepower/torque, which is a
totally separate issue. To be sure, some of it does revolve
around engine design such as compression ratio and a couple
of responders mentioned spark timing.

But beyond that is the fact that alcohol fuels carry a
portion of the oxidizer (oxygen) into the chamber with them.
One of the biggest factors that limit peak horsepower is the
fact that there is a maximum amount of gas-phase oxidizer
(air) that can occupy the combustion chamber at whatever the
chamber pressure happens to be (e.g., at WOT close to
atmospheric pressure).

Gases occupy a lot of space, so on a mass basis
there's only so much oxygen in there. Therefore, there is a
limit to the amount of fuel you can meter and still get the
mix to burn.

But an alcohol fuel carries a portion of the oxidizer with
it in liquid phase, which means I can pack a lot more in.
More oxidizer means I can put more fuel in too, which means
more peak horsepower as compared to fuels that get all their
oxidizer (air) in a gas phase.

However, because alcohols generally have lower energy
content as compared to straight gasoline per comparative
unit volume, the fuel economy is
lower.

That why racers and hot rodders, as Randy noted, like
alcohol fuels -- you get more power from them.

However in order to take advantage of that property you have
to have a fuel system with the ability to meter the required
fuel. Additionally, you can get even more power by taking
advantage of the octane rating and changing engine design
parameters such as compression ratio and spark timing.
Jim Kemper
Educator/Instructor/Government Representative
Colorado Department of Health
Denver, Colorado, USA"