Charger Forums banner
1 - 20 of 33 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 ·
So installing CAI brings an incrase in colder air into the engine? I am having difficulty seeing how this works without the CAI being fed air from a hood scoop or some similar outside air source. If the CAI is installed under the hood it seems like it is sucking in 180 degree air so how does it cool it or is it the 180 degree air that is fed to the engine? I am sure this has been discussed many time before so sorry for the "old" question. I am preparing to begin some mods and I think this may be my first one. I am not a great or even a good mechanic. This seems like a pretty basic install so I thought it would be a good place to start and build up my confidence that I can do this.
 

·
Registered
Joined
·
130 Posts
It is sucking in Hot Air in most cases, on other cars I have owned they called shem Short Ait Intakes in this configuration, reducing restrictions, but not bringing in "Cold Air"

IMHO a true cold air intake like the Voliant (sp?) and a few others that pull air from below the car or beind the lower grill are Cold Air Intakes, but most like the Mopar one are not.

I am sure someone will now say I am wrong, what do I know I am a computer guy anyways:)
 

·
Registered
Joined
·
2,554 Posts
It is sucking in Hot Air in most cases, on other cars I have owned they called shem Short Ait Intakes in this configuration, reducing restrictions, but not bringing in "Cold Air"
Once you get moving, I can't believe the engine bay is so sealed that the air in there is actually that much warmer than the ambient temperature outside. So is that what you would consider "Hot Air"?

Start rolling and the 80 degree air (or 30 here in the winter) immediately comes into the bay. Even the initial gulp will be ambient unless you've been stopped and the engine is still hot from the previous drive.

Or am I wrong?
 

·
Registered
Joined
·
3,862 Posts
Once you get moving, I can't believe the engine bay is so sealed that the air in there is actually that much warmer than the ambient temperature outside.
The engine is essentially standing right in front of air that is being blown through the radiator. So I'd say the air behind the radiator is going to be hotter than the air in front of it (ie. outside). If the air intake is located anywhere behind this radiator (ie. in the engine compartment), it's most likely going to be hotter-than-outside air.
 

·
Registered
Joined
·
2,554 Posts
The engine is essentially standing right in front of air that is being blown through the radiator. So I'd say the air behind the radiator is going to be hotter than the air in front of it (ie. outside). If the air intake is located anywhere behind this radiator (ie. in the engine compartment), it's most likely going to be hotter-than-outside air.
Good point, didn't think about the radiator. Still... the radiator is not 100% efficient - meaning the air won't be warmed completely to the core temp of the radiator as it flows through. Right? I'm really getting in over my head at this point.
 

·
Registered
Joined
·
1,904 Posts
At least on the 5.7's, hence the 6.1's I'm sure, the air intake extends to the left side of the vechicle. There's a hole in the body below the air intake. My stock R/T with Road and Track had its air filter box situated right over this hole.

I don't know if the design of the car pushes air up through that hole. But, it is moved out of the direct path of the radiator somewhat. I do konw that after I've stopped, my intake tube is quite warm, proving that at least then, the air coming through it would be warmed too. I've never had a chance to ride under the hood to see what happens once the car gets moving!
 

·
Registered
Joined
·
3,168 Posts
some one else pointed this out recently so ima regurge. and btw it makes total sense to me, i work with airflow for a living.

any one got a number of CFM(cubic feet a minute) of air that our engine moves?(i.e. sucks in) and if you do... do you think there is that much air inside your engine compartment that is hot from your engine at any time other than when sitting still?

as soon as you start this car it probably compeltely clears all air from under your hood and starts sucking up air moving in from the ouitside. and helping suck it in.

the air the intake brings in hardly has time to gain more than a couple degrees(if that) while moving thru your engine compartment and into your intake after it has digested the stagnent air from when you were sitting still.

im not saying that its 100% cool outside air, but i think it is a LOT more cool air than most people realize.
 

·
Registered
Joined
·
3,168 Posts
Once you get moving, I can't believe the engine bay is so sealed that the air in there is actually that much warmer than the ambient temperature outside. So is that what you would consider "Hot Air"?

Start rolling and the 80 degree air (or 30 here in the winter) immediately comes into the bay. Even the initial gulp will be ambient unless you've been stopped and the engine is still hot from the previous drive.

Or am I wrong?

your coorect, i missed your response, pretty much the same as mine. i design a/c systems for a living and this IS how things work. your engine cannot physicaly possibly heat the new air fast enough before it is taken in and combusted. it just cant.
 

·
Registered
Joined
·
3,886 Posts
So installing CAI brings an incrase in colder air into the engine? I am having difficulty seeing how this works without the CAI being fed air from a hood scoop or some similar outside air source. If the CAI is installed under the hood it seems like it is sucking in 180 degree air so how does it cool it or is it the 180 degree air that is fed to the engine? I am sure this has been discussed many time before so sorry for the "old" question. I am preparing to begin some mods and I think this may be my first one. I am not a great or even a good mechanic. This seems like a pretty basic install so I thought it would be a good place to start and build up my confidence that I can do this.
A CAI is usually designed to pull air that is farther away from the engine and insulate it on it's way back into the engine. An engine is hot, so the closer your intake is to the engine the hotter the air you are going to pull. Aside from that, I think the HP gain from a CAI comes more from the fact that you get more air flow rather than getting colder air.
 

·
Registered
Joined
·
3,160 Posts
the only "cold" air intakes are the volant and the gsm. both of those pull air from down under the radiator. the problem with them is that they cant be dyno tested because when cars are on the dyno they sit still and usually the hoods are open so all the physics, airflow, and high pressure zones are screwed up. all the other aftermarket intakes have the advantage of cone shaped filters instead of a panel. this means the filter will have more surface area and cause less restriction, thus the engine can get more air, but it probably wont be colder. these are the types of intakes that show gains on the dyno, and everyone on the forum buys.
 

·
Registered
Joined
·
928 Posts
someone did this math a while ago on one of the CAI's it worked out to something like 174 filter or tube volumes per second at WOT (either way ALOT OF AIR). good luck heating up the air in that amount of time.

also the second you start moving, air is moving into your engine compartment. And that intake is sucking air as fast as it can, there wouldnt be more than like 1-2 degree difference MAX between a TRUE CAI and a tube intake like most of us have.

also keep in mind a snorkel works regardless of whats in it, I live in oregon and if i hit a big puddle and dip my bumper into it, my intake is not gonna be slurping up water unlike a snorkle system.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #13 ·
Thanks for all of the great input! I am sold on the idea that their is no way that much air can get heated up by the engine in such a short amount of time.
 

·
Registered
Joined
·
136 Posts
I would think I could add in some technical input on this, since I took Heat Transfer and a Heating, Ventilation, and AC class in college but I guess I wasnt paying any attention....:smoke:
 

·
Registered
Joined
·
1,904 Posts

·
Registered
Joined
·
2,387 Posts
The term Cold air Intake is just a selling prop, the only way the intake is a cold air intake is when its cold outside and engine bay temps are lower from the cold air and when it would be poss to get a shot of the colder denser outside air, in the spring summers months you have nothing but a hot air intake and a noise maker...i like the open air intake term you got a third vote here...basically all a cai is a showpiece...they really dont add too much hp...but they look cool on an engine and make mean noises...and suck hot air in the corresponding months...only a ram air setup or some sort of tube that sticks outside the car somewhere will get you some cool air, but most ram airs only work when the car is in motion...just my .2 cents...
 

·
Registered
Joined
·
3,862 Posts
Simple way to figure this out...

At any hardware store around here, one can easily obtain one of those digital thermometers with two probes (one in the housing itself and one "remote" with a long wire). Get one with a hi/lo memory.

Run the long wired sensor to the area around where you expect the air to be picked up from by the "cold air" intake. Drive around a bit, let your car get nice and hot.

Observe the temperature readings you'll see from both the remote and the local sensors. Take note of their respective maximum readings. This will end the debate once and for all, either way.
 

·
Registered
Joined
·
7,323 Posts
the problem with them is that they cant be dyno tested because when cars are on the dyno they sit still and usually the hoods are open so all the physics, airflow, and high pressure zones are screwed up.
Convenient, eh? :D

Until someone can prove to me that the stock air box is a choke point, I remain unconvinced that any of the aftermarket "cold air intakes" do anything other than make more noise. I have a hard time believing the stocker can't flow enough air to satisfy our engines (without forced induction). In theory, you could make 2 dyno runs...one with everything stock and one with the airbox and snorkel completely removed (absolutely nothing in front of the TB) to see if there is any restriction there whatsoever.

Best,
 
1 - 20 of 33 Posts
Top