i know that they increase horsepower and al that, but why exactly? is it because the intake is wider than the stock intake, therefore allowing more air to get to the engine? does the name imply that the benefit comes from the air being cold?

how does having a CAI affect fuel efficiency?

obviously a lot of info gets kicked around about CAIs but my searches revealed nothing but DIY instructions and bickering about which brand is better. nothing about the theory behind it, which appears to be what this forum is for. any info?

 

the colder and less dense the air then more HP's. I got a CAI and i actually just got the Hondata Intake manifold gasket. I drove for about 2 hours straight yesterday and my Intake manifold is luke warm now instead of scorching hot!!! its great. When i put on ym cold air extension i noticed better gas mileage, i ususally got about 300 to a full tank, now i get about 320-330. All in all its a great mod. CAI OR NOTHING!!!!

 

To calculate air density, use the Ideal Gas Law equation solved for density. The equation is:

D=P/(T*R)

according to this equation, i believe cold air is more dense cause you will be dividing my a smaller denominator. also the particles of air are more closely packed together when its cold, warm the air particles are more widespread which is why warm air rises and cold air settles to the ground. since the air is more dense you will be taking in more oxygen for combustion. same concept as running air through an intercooler for turbos, you have more dense air per psi since the air is cooler.

 

my mistake, the density does go up, the cold air is more dense... sorry bout that

 

The tempature of the air is only a very small portion of Cold Air intakes.

For every 11 degree's the tempature drops, you gain aprox. 1% hp to the crank.

So if the engine bay is 100 degree's, and outside is 80 degree's, on a GSR you are looking at 3hp to the crank more. Thats even less to the wheels. Whoopty do, nothing to get excited about.

The length and diameter are what are important.

What are the basics of generating HP?

More Air + More Fuel = More power.

Intakes have freer flowing air filters, and larger piping than the stock intake. This alows the engine to breath in more air, add more fuel and make more power. The reason why Cold air intakes are so popular, is because the length causes the air to travel faster causing volumetric effeciency to happen earlier. The result is a hump of HP from 4-5k, which makes everyone feel like their car is pulling very hard all of a sudden. Gotta love the butt dyno.

As far as custom piping, or off brand intakes.. if its the same diameter, and has a decent filter, its going to perform the same.

 

don't engine bays get a whole lot hotter than 100 degrees? Never really measured the temp, but i'd bet somewhere in the upper 100s at least.

 

Even still, once you get moving the engine bay is filled with cool air from the outside and its no longer sucking in hot air from the engine.

You might have 3-4whp advantage up to 25-30mph, but after that its all the same. The main charectoristic is the length and size of the tubing.

 

no way, CAI is way better then short ram... lower temps at all times and speeds

 

so you have done tests to prove in every single situation a CAI is better and has lower temps at all temps and speeds?

I have seen test that show only a 1 degree difference in air tempature at the throttle body when moving at 30mph.

Also, when supercharging you don't want a CAI.

Why? Because #1 with a supercharger you want a lot of air, quick.
#2, the blower is going to heat up the air so much it doesn't matter if it was cold at some point.

you definetly need to read up on intakes before you make broad generlizations and assumptions like that.