67mustang302

Both to a degree. There is water vapor in the air inducted, so what goes in must come out. But water vaporalso is a large by-product of combustion along with CO2. Gasoline is a hydrocarbon chain, meaning it's comprised of a chain of hydrogen and carbon atoms, which break apart during combustion(oxidation). The hydrogen combines with some ofthe oxygen from the process creating water vapor, and the carbon combines with some of the oxygen producing CO and CO2, primarily. You can also have other varrying byproducts, such as NOx if you run lean, extra oxygen combining with nitrogen(most abundant atmospheric gas)with the heat/pressure from combustion as a catalyst, unburned HC as well if you run too rich. But primarily the byproducts of any hydrocarbon oxidation processare carbon dioxide and water, if it's a clean and efficient combustion. Natural gas, gasoline, oil, deisel, propane etc etc.

For those of you who know chemistry, it'd be 2C8H18(isooctane) + 25O2 = 16CO2 + 18H2O. As you can see by this too, that with a"typical" gasoline molecule(isooctane) you need 25 oxygen molecules just to burn 2 gasoline molecules at stoichiometric, to give you an idea of how little fuel and how much air is needed.

http://www.altfuels.org/backgrnd/fuelchem.html some stuff on combustion of different fuels.

67mustang302

Blah, you beat me.

And incidently, when you try to use the subscript numbers in chemical equations, this forum freaks and spits out wierd characters in stead of small numbers. [>:]

289FB

Guys thank you for allyour answers

rmodel65

water is a sign of efficient combustion

67 evil eleanor

+1 on the H20. Given the info, if you increase the A/F ratio (more oxygen) within the lower rpm range (less than 2000 only), do you guys think the enginewillrun cooler?Just courious what you guys think.

1967inline6MUSTANG

some great info...like going to science class..wow

Kramer

when you run an exhaust gas analyzer you usually can get a 4 or 5 gas check they are O2, CO, Co2, HC, and NOx

NOx is from high temperatures causingoxygen to turn into nitrogen with the extra electron

O2 is oxygen not used

COis incomplete combustion (not enough o2 for the HC)

CO2 is complete combustion and

HC is unburnt fuel

the rest is H2O as everyone said, and normal air that is not used like nitrogen and other stuff

67mustang302

NOx is oxygen and nitrogen combining from high heat, extra oxygen and a lot of nitrogen(78%) in the air. That's why it's called NOx, oxides of nitrogen. Like anything that's oxidized, it has oxygen attached to it. Technically, water is oxidized hydrogen. Rust is iron oxide, corroded aluminum is aluminum oxide etc etc.

Oxygen turning into nitrogen could only occur through a fission process at the atomic level(breaking off of a single proton), ie nuclear fission.

bluovalguy

Hated chemistry in high school, and after all these years I still hate it

69thunder

No water out the tailpipe if the incoming air is 100% dry? That is the best one I have heard in a long time.....