Does a cold air intake add power on a 4.0?

I don’t think anyone has ever claimed that a freer flowing intake isn’t an improvement.
The issue is that a 1-5% improvement isn’t noticeable.
With that said, using a high flow filter in conjunction with other improvements such as better exhaust, MIGHT make enough of a change that you can feel it while driving rather than simply measuring it on a dyno.
 
WestCoastDan said:
I don’t think anyone has ever claimed that a freer flowing intake isn’t an improvement.
The issue is that a 1-5% improvement isn’t noticeable.
With that said, using a high flow filter in conjunction with other improvements such as better exhaust, MIGHT make enough of a change that you can feel it while driving rather than simply measuring it on a dyno.
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You may want to reread this thread. The claim has been made repeatedly that there is no improvement to be had. None, and the factory setup will flow all the air the engine can use. Mopar disagrees apparently.
 
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Jezza said:
You may want to reread this thread. The claim has been made repeatedly that there is no improvement to be had. None, and the factory setup will flow all the air the engine can use. Mopar disagrees apparently.
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I guess you missed the point entirely.

An improvement that you cannot feel or measure in real world use, isn’t much of an improvement.
If the gains from this filter were appreciable, the MOPAR document would have certainly claimed them to provide “X%” improvement, yet the claim is rather ambiguous at best.

Go ahead and buy your “performance” filter and see how much improvement you can feel.
 
WestCoastDan said:
I guess you missed the point entirely.

An improvement that you cannot feel or measure in real world use, isn’t much of an improvement.
If the gains from this filter were appreciable, the MOPAR document would have certainly claimed them to provide “X%” improvement, yet the claim is rather ambiguous at best.

Go ahead and buy your “performance” filter and see how much improvement you can feel.
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It clearly can be measured. Feel is relative and would depend multiple variables including the individual's ability to perceive changes in acceleration.
 
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Not really interested in more HP, but any gains to be had anywhere not pulling 200 degree air into the engine?

Stock intake setup not pulling air from under the hood was my thought.
 
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CMBD said:
Not really interested in more HP, but any gains to be had anywhere not pulling 200 degree air into the engine?

Stock intake setup not pulling air from under the hood was my thought.
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All the "cold air" kits I have seen pull air from the same location as the stock airbox. Only a snorkel kit or cowl kit would offer lower temp air sources. If it was a street only rig you could pull from under the front bumper area, but water would be able to flood it out if you weren't careful.
 
Jezza said:
All the "cold air" kits I have seen pull air from the same location as the stock airbox. Only a snorkel kit or cowl kit would offer lower temp air sources. If it was a street only rig you could pull from under the front bumper area, but water would be able to flood it out if you weren't careful.
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I wouldn't use a kit. I would remove the inlet off the stock box, and fab a sheet metal assembly to go between the box core support. Would seal it up and pull air through the headlight opening. I dont do deep water.
 
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CMBD said:
I wouldn't use a kit. I would remove the inlet off the stock box, and fab a sheet metal assembly to go between the box core support. Would seal it up and pull air through the headlight opening. I dont do deep water.
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One of the issues with the stock assembly is the filter itself. The 4.0 has the ability to flow 300-350 CFM of air at WOT. The factory panel filter is roughly 200 CFM. That leaves over 100 CFM deficit. That Windstar filter flows closer to 350 CFM. Both are paper filters and both are easy to acquire.
 
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CMBD said:
I like that. Thank you. Have seen it before and forgot about it.

Will put it on my things to do when I run out of stuff to do list 😃
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It's also worth a look at the F and E series filters. The filter assembly in my E450 motorhome has a similar style filter assembly to the Windstar but has a filter that flows 500 CFM.
 
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I had a chance to measure my IAT, different position on the 05 than the previous years. But 102 degrees on the weather app and 109 on the intake temp- hard duct to behind the headlight-In all the discussions I wonder if its lost this could be categorized as power preservation? The initial under hood temps at start up are ambient and the you get a gradual fade as temps rise. At least that is part of my thinking.

IMG_3708.jpeg
 
Jezza said:
One of the issues with the stock assembly is the filter itself. The 4.0 has the ability to flow 300-350 CFM of air at WOT. The factory panel filter is roughly 200 CFM. That leaves over 100 CFM deficit. That Windstar filter flows closer to 350 CFM. Both are paper filters and both are easy to acquire.
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With that math removing the filter (or going to the windstar filter) would take you to nearly 300 hp :rolleyes:
 
srimes said:
With that math removing the filter (or going to the windstar filter) would take you to nearly 300 hp :rolleyes:
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I wish it were that easy, but a restrictive filter just creates a pressure drop across the element that restricts the engine's ability to draw in air. The amount of pressure drop would dictate the potential power losses. It's not 1:1 with relation to CFM.
 
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WestCoastDan said:
I don’t think anyone has ever claimed that a freer flowing intake isn’t an improvement.
The issue is that a 1-5% improvement isn’t noticeable.
Click to expand...
I guess you missed the point of this thread entirely. Many people said exactly that there are absolutely zero gains to be had. Many of us disagree while still not recommending running anything aftermarket intake wise for almost all TJ drivers. We say there are improvements to be had, but they are small and in a part of the rpm range most TJ owners won't find useful. Those are not the same things. But everybody is generally recommending the same thing in the end. It's just one recommendation comes from facts and testing, and the other comes from opinion and hearsay. I'd personally rather understand why things work the way they do.

You are agreeing with us, not them. And I'll further comment there are some unique cases where TJs do enjoy real works benefits from increased intake flow. Like a built strokers or turbo'd motors for example.
 
Jezza said:
I wish it were that easy, but a restrictive filter just creates a pressure drop across the element that restricts the engine's ability to draw in air. The amount of pressure drop would dictate the potential power losses. It's not 1:1 with relation to CFM.
Click to expand...

Funny how a guy can come in with actual data and numbers that mean something, and get swatted at by someone that doesn't bring anything to the table but nonsense and the emoji list.
 
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Jezza said:
Read this today in an old Mopar manual. I wonder if this bit of information will convince those who believe there is no benefit to replacing the factory filter.

View attachment 444121
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That wouldn't be the first thing they got wrong when writing the FSM. Even the chief Jeep engineer, James Repp, has confirmed over the years that the OEM stock/factory air intake system easily flows more air than the 4.0 can consume at WOT at redline rpms.
 
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