Cold air through intake idea

Okay, so more compression means more horse power, right?

When air cools it contracts, so I got this idea:

What if I created a box on the intake that cools down the air before it enters the carb? I don't know how I'd accomplish this, but let's just say hypothetically this were possible.

Since the cool air is contracted air, theoretically, wouldn't it expand inside the cylinder during fuel explosion, therefore creating more compression?

I haven't tried this yet, but I might consider it if the idea is sound. Anyone here have any input? I don't live in a cold climate so I don't know, but does riding in cold weather increase performance at all?

wheelbender6 said:

One member made a ram air intake for his filter from PVC pipe. The faster you travel, the faster air enters the intake.

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I've actually done something similar to the ram air system by surrounding my air filter with the bottom of a can in order to push moving air into the carb. Like this:



Doesn't do quite enough to add noticeable power, but it does seem to lean out the mixture just enough that most of the normal 4 stroking goes away.

The difference between my idea and a ram air system is that a ram air system pushes air into the carb and also leans out the fuel injection(not to be confused with a "fuel injection" system). My idea would instead(or in conjunction with a ram air system) would make the air going into the intake very cold; that way that when it enters the cylinder and the fuel explodes, the cold air is suddenly heated and expands more than warm air would. At least that's my hypothesis.

The problem is I don't know how cold the air would have to get for there to be any noticeable increase in compression, so if it turns out that the air would need to be extremely cold, I'd need to find a way to make the air extremely cold quickly enough before it enters the carb.

This is why I'm wondering if cold weather has any effect on performance(other than freezing your fuel). If it does, then I'd have reason to continue with figuring out how to make this work.

I'd get an expansion chamber if I had the money! Or the willingness to have my pedals always cling up against something metal, or have a piece of extremely hot tubing right under my seat.

I disagree about the ram air not working. With my crappy pineapple can setup, I don't think I get more horse power, but it seems to help lean out the mixture just enough that 4 stroking through normal operation is almost eliminated. The NT carbs often run a little rich anyway.

Wouldn't CO2 effect the explosion inside the cylinder since it would be displacing oxygen? I'd think it would act as an explosive retardant. It would be one thing if it were on the outside, but I'd think it would be a bad idea to have the air pass directly over dry ice to cool it. Regular ice may work just fine as long as no water gets into the carb/engine.

biknut said:

In theory since cool air is denser than warm air, shouldn't you have potential for more power because, denser air = more oxygen?

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True, compact air would contain more oxygen than less-compressed air taking up the same amount of space.

Yeah, oxygen is an interesting idea, but I'm not sure I want to accidentally turn an oxy tank into a rocket!

I have a leftover CPU heat sink. Maybe I can make a box where the bottom of the sink touches ice or dry ice, and the air passes through the fins making it cool down before it enters the carb?