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School me on Cold Air Intakes

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Old Apr 15, 2017 | 02:52 PM
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Year: 2004 WJ, 1998 XJ
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Default School me on Cold Air Intakes

Going to look at an 04 Overland Edition with a cold air intake. Has 147k miles The filter looks filthy. That concerns me some because this is an easy maintenance part and if that was left go, what else was. Was never a big fan of K&N either, but not for any real reason. Is this really worth having on there? How difficult and expensive is to put it back to stock? I'm reading that it seems to only makes it sound better. I don't care how it sounds. It's plenty powerful enough for me. I want longevity and reliability. I am meticulous with maintenance.
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Old Apr 15, 2017 | 06:05 PM
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If you're looking for my opinion, lab flow tests show that the stock flat pad air filters flow more than 4 times the air the engine can ever draw at any throttle setting, IF THEY ARE CLEAN AND DRY! The stock induction setup takes cooler air from in front of the radiator, filters it, and delivers it to the engine in the most efficient flow path that will fit under the hood. It is also sealed from underhood air that is warmer and usually has a diverter in the intake horn that separates water from soaking the filter pad. Remember, wet paper does not flow air very well. Oiled paper also get plugged quickly.

People think that if you can hear the resonant howl of the intake, you're getting all the air it can possibly draw and it sounds cool! What you're actually hearing is a pressure wave every time an intake valve closes. It has nothing to do with max air flow. Many manufacturers have spent expensive hours trying to eliminate those pressure waves for a smoother airflow. Some intake manifolds actually use those pressure waves to pack the next cylinder with air.

The only way to effectively increase an engine's power using the induction system is to raise the pressure of the incoming air by the ram effect of forward motion or by turbo or super charging. The air taken in from in front of the radiator IS high pressure air. Also, volumetric efficiency increases 1% for every 10* drop in temperature and humid air is heavier.

These are my opinions but are based on SCIENCE!

Last edited by dave1123; Apr 15, 2017 at 06:12 PM.
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Old Apr 15, 2017 | 06:07 PM
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Originally Posted by dave1123
If you're looking for my opinion, lab flow tests show that the stock flat pad air filters flow more than 4 times the air the engine can ever draw at any throttle setting, IF THEY ARE CLEAN AND DRY! The stock induction setup takes cooler air from in front of the radiator, filters it, and delivers it to the engine in the most efficient flow path that will fit under the hood. It is also sealed from underhood air that is warmer and usually has a diverter in the intake horn that separates water from soaking the filter pad. Remember, wet paper does not flow air very well. Oiled paper also get plugged quickly.

People think that if you can hear the resonant howl of the intake, you're getting all the air it can possibly draw and it sounds cool! What you're actually hearing is a pressure wave every time an intake valve closes. It has nothing to do with max air flow. Many manufacturers have spent expensive hours trying to eliminate those pressure waves for a smoother airflow. Some intake manifolds actually use those pressure waves to pack the next cylinder with air.

These are my opinions only, but are based on SCIENCE!

The only way to effectively increase an engine's power using the induction system is to raise the pressure of the incoming air by the ram effect of forward motion or by turbo or super charging. The air taken in from in front of the radiator IS high pressure air.
So what parts do I need to put it back to stock? Is that junk yard stuff or should I buy that online?
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Old Apr 15, 2017 | 06:16 PM
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You'll spend much more money online than at a junkyard. The problem is finding one that hasn't been raped for other parts and the filter system lying around in pieces.
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Old Apr 15, 2017 | 06:59 PM
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Originally Posted by dave1123
You'll spend much more money online than at a junkyard. The problem is finding one that hasn't been raped for other parts and the filter system lying around in pieces.
Yeah figured that. Besides the intake cover, filter housing and tubing, what other parts would I need?
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Old Jul 5, 2017 | 02:30 PM
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The air intake horn that goes to the radiator support bulkhead. I'd say that's the most important part.
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Old Jul 12, 2017 | 12:03 PM
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I'm sure someone who is wanting a CAI would swap you for stock stuff. Could be an easy win win for both parties.

Max
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Old Jul 14, 2017 | 06:27 PM
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His appears to actually be shielded from the engine bay air for the most part. The one that was put on mine however, (a long time before I got it) started life as a k&n "cold air intake" and had since for some unknown reason, a spectra filter on it and it's wide open to the engine bay.... have debated a snorkel, but not a fan of the look of them but want the higher air intake than anything in the hood. Delema...
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Old Jul 14, 2017 | 06:32 PM
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