Originally Posted by Zriuz

water injection is the S*** 3 years of ultra abuse on my rotary and still perfect... KNOCK OWNED

Originally Posted by schim187

I was reading up on water/meth injection...lamans terms said that as water was injected into the system post-turbo and inducted into the motor, it would evaporate once inside the combustion chamber, taking away extra heat--hence added cooling.
The methanol part is used as a detonation preventative (raises octane) so that you could advance timing more for extra tunage.

I've heard that windshield wiper fluid works great as long as you dont use the glycol based fluid.

Originally Posted by wafflesincars

There seems to be a bit of confusion of what the actual benefits of water injection are, essentially by introducing extra mols of Oxygen to the combustion reaction in an engine you are effectively raising the level of energy (heat) needed to react the components, which allows you to compress more gas (producing heat) without having the mixture ignite at the improper time, (better known as detonation).

The easy way to express this is to say that adding Oxygen effectively raises the detonation threshold......

.........What water injection allows you to do is add more molecules of Oxygen to the mixture, essentially raising the "octane rating" of the fuel, the more molecules of reactant the longer the reaction will take, the less preignition/detonation you will have (detonation occurs when the fuel mixture ignites spontaneously at random intervals due to heat, usually collections of matter with different thermal properties than the rest of the metal cause "hotspots"; carbon deposits built up over time are the most common). The introduction of a molecule with a high specific heat capacity also keeps ignition temps reasonable, versus a lean mixture which will incur more heat (less fuel to react and carry away the heat).......


........o, water is an oxidation agent as well, it's highly reactive, especially in a combustion reaction where there is so much heat.

The water vaporizes, it never evaporates, i.e. it enters as water and in the combustion reaction gets split into Hydrogen and Oxygen separately, it reforms with excess molecules later. There is some amount of heat absorbed, but it's there for effectively the same reason the alcohol is, raising the octane...

Originally Posted by patsmx5

For the most part I agree with everything you've said, but this part not so. Are you saying that spraying water in the motor adds oxygen? Or are you saying it will suppress detonation and allow you to add more oxygen to make more power? I'll agree with the later. I think that's what your saying, but it's wordy at best. No, now I see you do say it's an oxidizer in a combustion event. How so? I don't think that's correct. If it did, then the hydrogen would react with the oxygen. If that were so, then we could simply spray LOTS of water in the motor with just enough fuel to get the reaction going. In this case we wouldn't need a turbocharger at all, just gas and air to get the reaction going to burn the water.

In simple terms, the water goes through a phase change during the compression stroke, which removes a significant amount of heat from the charge, suppressing detonation. In turn, you can now effectively increase boost to add more oxygen.