warm/cold air intake, something thant made me think a bit. Options

[4-eyed-freek]

hey everyone! im a current student at UTI in chicago and last week my brakes teacher was lecturing on how stupid cold air intakes we and he kept calling them a warm air intakes, and he is right in a way..... BUT this week i started my basic engines class and my new teacher couldnt stress the inportance of a cai on a car because...(THIS IS WHAT HE SAID) if you think about it, your engine is running at somewhere around 212 in most cars. so the 100+ degree temp in your enigine bay that your cold air intake is taking in is actually colder than your internal engine thus meaning that the really warm air in you engine bay is actually cold air for your car.. so who is right?!?!?! i thought about this to myself and talked it over with other kids in the class and i got so many diff. answers. lets here what you guys think.

[richee3]

What your teacher was referring to as a "warm air intake" is actually a short ram intake, NOT a cold air intake. It does suck in warm air from the engine bay. It will add a tiny amount of power, if anything. However, a true cold air intake will have a few feet of piping and will get the air filter out of the engine bay, where it's sucking in cooler air. If I recall correctly, the best air temperature for your engine is between 50-70. (Somebody feel free to correct me on that.) A true cold air intake will still only add a few horsepower, but it's more effective than a short ram intake, or "warm air intake."

Short ram intake:


Cold air intake:


Notice how the cold air intake has a lot more piping and it moves the air filter away from the engine. In the case of a 7th gen Celica, and this is fairly standard, the air filter ends up inside the fender where it's not getting any warm air from the engine at all. Hope this helps.

[350niZmo]

i would have to agree with richee3.... a short ram intake will only produce a small amount of power while consuming all the hot air that surrounds it in the engine bay. I would say going with a cold air intake would be a better choice since these are located near the front bumper or fender wall where they are absorbing more fresh air than a short ram. but thats my opinion.

my answer: going with a cold air would be better but you run a higher risk of HYDRO LOCK if you live in a state where you get heavy rain. if you go CAI get a water by-pass valve.

This post has been edited by 350niZmo: Oct 8, 2010 - 10:54 AM

[4-eyed-freek]

well like my engines teacher stated any air comming into the filter is better than the stock air box because your normal engine running temp is aournd 212 for most cars, now .. the engine bay temp should be no where near 212. but my brakes teacher sair stick with the stock air bot because all your doing is sucking warm air in, and i thought they were both right in there own seperate ways.

[richee3]

They are both right. They're both talking about two similar but different intakes. A short ram intake has the upside of being able to suck air in more freely than the factory intake, but it's warmer air than the factory intake. A cold air intake sucks more air in than the factory intake, but it's also getting cooler air than a SRI, so it's getting slight power gains. However, without a full exhaust setup, neither type of intake is going to give you big gains.

Short ram intake- Upside is that it sucks more air in than the factory box. More air = more power. However, it's sucking in warmer air from the engine. Cold air is more dense, so a CAI can suck more air in. Plus colder air is better when the air/fuel mixture combusts.

Cold air intake- The upside is that it flows better than a factory box, and that it sucks in similar air temperatures as the factory box rather than warm air from the engine. The downside is that the piping length is much longer, and as 350niZmo mentioned, hydrolock is always a concern.

[Tom_SS2]

the cooler the air the denser it is, denser means more basically, more air means more fuel is needed, more air and more fuel means more power,

a modified standard airbox with a performance panel filter is better then an SRI as it will be sucking in cooler (denser) air, but it won't sound as sweet

[4-eyed-freek]

well my brakes teacher doesnt know the differance... he was just saying that its a waist of time and money because your putting something on your car that sucks warm air into a warm engine.... my other teacher says its the best thing you can do because although you are taking in 100+ degree heat your engine is running at 212 ish. ... so thus makeing that 100+ temp heat actually good for your engine because its much cooler than what your engine is running at.

[Hanyo]

The discussion of what kind of intake system is best is like splitting hairs.

The maximum horse power increase would be 1-5 horse power.

There are two major disadvantages to a cold air intake 1) the cold air intake requires more piping therefore increase weight of the car. 2) A cold air intake routes the air through a longer path so the air must move a greater distance before entering the cylinders.


The short ram intake in the other had does in fact take in warm air. But it has several advantages 1) it shortens the path the air must travel, 2) its much lighter then the stock intake system.

With all these advantages and disadvantages which answer is right?

Well this get complicated. The final deciding factor is the cars design and the difference in engine bay temperature vs the air outside. If your car had the GT4 front end with tons of ventilation, and your car is moving around 45 mph; the air temperature under the hood is only going to be 50 degrees hotter then the air outside. It this example it just might be worth while to use a short ram intake.

Another example where a cold air intake is best would be in a ford windstar or similar set up. Where the engine bay is stuffed with engine and there is little to no ventilation. A warm air intake will be sucking in super hot air.

To add more fuel to this fire, we can then talk about engine tuning, turbos, scavenging, ram air, individual throttle bodies. Once you look into those engine set up there is no right or wrong answer about which intake system to use.

[delusionz]

short ram (no idea why its called ram, nothing gets rammed in at all) is the worst setup of the lot - its better at night, but its worse during the day

panel filter in the stock air box is an improvement, but the stock air box is still very restrictive

piping the airfilter to the front bumper is by far better, it improves engine response significantly and is a relatively easy option

the best option is moving the battery to the boot and making a custom air box to house your podfilter with a larger diameter duct piped to the front of your bumper giving the benefits of rammed cold air, and the shorter length piping from the throttlebody or turbo to the air filter.

[czwalga]

I think both teachers are wrong. It's cooler than the engine operating temp, so it is cooler. At the same time its definatly not essential. Take a completely stock GT, add a CAI. If you picked up more than 3 fwhp, i'd be shocked.

[HectortheRican]

I think both teachers are wrong. It's cooler than the engine operating temp, so it is cooler. At the same time its definatly not essential. Take a completely stock GT, add a CAI. If you picked up more than 3 fwhp, i'd be shocked.

x2

One thing I don't understand though is if the max we can pick up from a CAI is about 2-3hp, how come all the CAIs I see for say, a G35 or WRX, Evo, 350X or S2000 say gains of anywhere from 15 to 30hp?

This post has been edited by HectortheRican: Oct 28, 2010 - 9:31 AM

[4-eyed-freek]

its all about the turbo's.. just like if you added an exhaust system to an sti, you can see anywhere 15 to 30hp gains. turbo's need to breath and let there exhaust out with as fast and as simple as possible.

[czwalga]

I think both teachers are wrong. It's cooler than the engine operating temp, so it is cooler. At the same time its definatly not essential. Take a completely stock GT, add a CAI. If you picked up more than 3 fwhp, i'd be shocked.

x2

One thing I don't understand though is if the max we can pick up from a CAI is about 2-3hp, how come all the CAIs I see for say, a G35 or WRX, Evo, 350X or S2000 say gains of anywhere from 15 to 30hp?

They are more limited by the intake being a restrictor than it is about the temperature of the air. Basically the engine is being choked by their small intake size.

[HectortheRican]

They are more limited by the intake being a restrictor than it is about the temperature of the air. Basically the engine is being choked by their small intake size.

its all about the turbo's.. just like if you added an exhaust system to an sti, you can see anywhere 15 to 30hp gains. turbo's need to breath and let there exhaust out with as fast and as simple as possible.

Now that makes some sense, thanks guys. And I accidentally typed 350X lolol

[mak5603]

This thread makes a lot of good points but is also filled with a lot of blanket statements and misleading information that are more or less just opinions...