With the interest of water/alcohol injection on the rise I’ve taken my usual technical look at its purpose. Simply put water/alcohol injection is for helping cool the intake air temperature after it’s been compressed by the turbo.

So that brings a question to mind:

What’s the stigma around using Nitrogen Oxide Systems? I’ve looked at this years ago and it’s basic principal is the same: to cool the intake air using an inert gas, similar to water, similar to alcohol… but it actually does it much more efficiently.

Yes, I’ve heard many stories on people blowing up their engines because they used Nitrogen Oxide. In the end it was just the same as tuning your engine to run way too lean… with our Evolution VIII’s we can do that without having an injection system of any kind!

After doing some looking around I’ve found that Nitrous Kits are pretty much in the same price range of decent water/alcohol injection kits. So why not Nitrous?

 

And for those technically savvy folks... Doesn't water injection is fact raise the humidity of the air going into the engine? With the generalization that turbo cars perform less in a humid climate how is this good?

Doesn't vaporizing water into the same air affect gas vaporization rates? Isn't this a bad thing?

 

Go look up the latent heat value of water and compare it to NO2. That should explain why water is better for det control which means you can tune for more power. Water injection is used for det control.

 

compare the cost of filling a nitrous bottle to the cost of filling some water and alcohol.

big difference in price. Especially if you use the nitrous a lot.

 

actually turbo cars perform better when the air is humid because it prevents detonation

 

H2O systems are for turning up boost, adding more margin of safety. N2O systems are about adding ponies. (yes this is the abridged explaination :P )

 

jj_008,
You're actually talking about two things:

1) Latent Heat (Value/Rate) of Vaporization: I haven't had a chance to find NO2's value but judging from your post you're probably implying NO2's value is less. Let's see if someone else can find this value before I do. Keep in mind that although cooler air helps deter detonation it's not really detonation control... but there's another angle:

2) Detonation Control: Do you mean that humid air will slow the flame front in the cylinder? Although this is good for detonation control I'm not sure how this is any better. A good example is the climate here in New England: During the summer when the air is humid I have to turn up the boost to match performance of the dryer/cooler air in the winter. So all I see water injection is something that makes intake air worse... then you have to dump more air in to overcome the water saturation which disguises itself as an ability to tune for more power.

Keep going... I still don't see water injection being better than Nitrous.

 

N20 basically explains it.. the big O part for oxygen. Add more oxygen-->add more gas-=more power... Some people do use nos for cooling the intercooler, but the cooling effect it has on the intake air temperature is just a bonus, the real reason why its used in the intake is for more oxygen for the same effect as a turbo.

 

This is the best argument I've see so far. I can't deny that water is cheaper than NO2.

Are the consumption rates the same?

 

um, My mistake Nitrous Oxide is N2O, Not NO2.

 

Netmand, I feel that you are terribly mis-informed. Let's look at alcohol injection in particular. As the alcohol is injected , it cools the charged air as it is vaporized and it also raises the octane level of the pump gas. Now you have cooler air (less combustible a/f mixture) and higher octane rating (less det) which is how people run 30 psi on pump gas. Water injection give 1/2 the benefits, but is also useful. Don't make stupid posts saying alcohol/water injection is a waste when people have/are/will use it with great success.

 

interesting info http://www.rallycars.com/Cars/WaterInjection.html

 

N2O is 376 KJ/kg & water is 2256 KJ/Kg. The water can absorb the energy of detenation 6 times greater then N20. But water injection and nitrous are used in different aspects of engine tuning and can't be compared.

 

Netmand:

Try taking a look at this thread as posted by David Burschur:

https://www.evolutionm.net/forums/sh...d.php?t=100883

Dont forget that alchohol injection increases the octane rating since ethanol is like 117 octane. If i'm understanding correctly, it dissapates heat better than fuel and raises octane without the need for exorbent amounts of additional fuel for power which N2O would need...

 

also, water/alcohol inj systems typically cost half what a wet kit cost... and with no2, you still need extra fuel to comp for the nitrous. not w/alchohol inj. and, alcohol cost sooo much less then filling up a bottle of spray.

and, for anyone who's streetraced... having a bottle in your trunk kills your chances of getting a decent race...but alch inj is very very hard to find if installed right...