Cold air and combustion. How cold is cold enough?

[Evolution1980]

I've been kicking this aronud for some time now.

Lately, all the rage has been "cold air induction" blah blah blah.
So this question has been in the back of my head.

How cold is cold? Is there a point of diminishing returns? Is there a cutoff point where it's too cold for optimum performance?
Would a gasoline combustion engine perform best in Antarctica versus Northern Alaska (or anywhere else for that matter...)

Also, I would think that at somepoint, humidity at certain temps will also play a role. So if that factors in to the equation as well, include that in the explaination.

On a possibly related topic, isn't this how N02 (NOS) functions? It's a delivery method for cooling the intake air charge and thus being able to carry more oxygen to the combustion chamber? (Or is there some reaction where the single nitrogen molecule or two oxygen molecules somehow get split apart from one another?)

[Edmond]

I've been thinking about this as well. But have you noticed how the car seems to run stronger at night when it's cooler?

What would be interesting would be if we had a track where we can test year round. Assuming that all the other factors are the same except for temperature, we could get somewhat scientific findings.

[Evolution1980]

But have you noticed how the car seems to run stronger at night when it's cooler?...What would be interesting would be if we had a track where we can test year round.

Yeah, it's cooler and the humidity is usually a bit lower at night. The air is "thinner"...less water in the air.

A controlled environment would suffice. To be able to get your car in a freezer like environment and/or where you can get freezing cold air shot at the intake...

Another quasi-related thought...
Instead of NO2, why not pure oxygen gas???

[Edmond]

Another thought:

What would be even easier would be to put the car on a dyno and see what it puts out in various temperatures. If it was done in the winter, we could dino it with the garage open. Then we would crank the heat up and dyno it again. I think that the engineers rated the cars with average room temperatures.

[Classicvette63]

I read a detailed description of what would happen if pure oxygen were used. The short version is: spontaneous, multi directional self-disassembly. Mixing pure oxygen, gas and spark is in essence, creating a really big bomb.

As to how cold is too cold? There is a point of diminishing returns, but cannot recall the exact temp. If I rember correctly, I think is is somewhere in the 50F range. Classic

[DRTH VTR]

I thought that Nitrous Oxide worked for two reasons.
First, it about 35% oxygen when it disassociates in the combustion chamber.
Second, it is COLD. I am not sure how cold, but it is way below environmental temperatures. The density of air increases with decreasing temperature. This results in more oxygen atoms per unit volume.