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Old 12-12-2012, 05:51 AM   #1
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Performance Question - air intakes

Are the after market cold air intake systems worth the money. They claim more horsepower and gas mileage. What's been your experience? Do they live up to their hype? They all look like a pretty easy install but do they work?

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Old 12-12-2012, 05:54 AM   #2
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The stock air box can flow more than the 4.0 can take in at wot so I see no need for a cai. Everyone on here says they're junk too so you'll never see one on my jeep.

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Old 12-12-2012, 08:48 AM   #3
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Old 12-12-2012, 08:57 AM   #4
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Originally Posted by 97wrangler-242 View Post
The stock air box can flow more than the 4.0 can take in at wot so I see no need for a cai. Everyone on here says they're junk too so you'll never see one on my jeep.
If this is true, then I would have to agree with them and just stick with stock. But with many vehicles, the more air you can draw into the engine, the better throttle response you will get. If you have a vehicle and it has an aftermarket intake on it, you will also notice that with the cooler air in the morning, the better it performs. Plus some stock intakes are very restrictive which limits the air intake and in turn limits your performance. I've had one before on a car and it did improve my performance but I wasn't all about the metrics seeing if it improved my gas mileage, etc. I just went by how it felt...lol
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Old 12-12-2012, 09:19 AM   #5
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I have it on one of my jeeps and really can't tell a difference.I think your stock breather with a good filter such as a k&n is probably as good as you can get
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Old 12-12-2012, 09:36 AM   #6
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If this were a forum for Mustang 5.0 or Camaro Z-28 enthusiasts, it'd be a universal yes that aftermarket air intakes can help improve performance for some engines... fairly substantially too since many air intakes like those are indeed restrictive.

But since this forum is for Wranglers whose air intakes were specifically designed to be non-restrictive, the answer is a resounding no to the question of if they will help with performance. As was well said above, the Wrangler's air intake is more than capable of easily flowing more air than the engine can consume at WOT (wide open throttle) and redline RPMs.

And the very last filter I would call 'good' is the K&N. In my strongest possible personal opinion, it is the worst filtering air filter of all that can be used in our Wranglers. It keeps as much dirt & harmful silica out of our engines as a screen door keeps dust out of the house during a Texas dust storm. I'd rather hit myself on the head with a hammer than run another K&N air filter in my Jeep as I stupidly did until 12-13 years ago when I figured out how much dirt it was letting into my engine. I ended up adding a prefilter on top of it trying to cut how much dirt was getting past it. One prefilter wasn't enough, I ended up having to run TWO prefilters until I could get rid of the K&N & go back to a paper element air filter.

This shows the two pre-filters, an Outerwears & an oiled foam Unifilter that I ended up adding trying to limit how much dirt that got past it and into my engine ...
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Old 12-12-2012, 09:41 AM   #7
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Thanks guys for the info. It would seem my $ will be better spent elsewhere - like a lift kit!!
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Old 12-12-2012, 09:42 AM   #8
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Thanks guys for the info. It would seem my $ will be better spent elsewhere - like a lift kit!!
Good decision.
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Old 12-12-2012, 09:43 AM   #9
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I think there should be a sticky for items that are a waste of money and useless on wranglers.
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Old 12-12-2012, 09:52 AM   #10
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I think there should be a sticky for items that are a waste of money and useless on wranglers.
Not sure anyone would use it, just like doing a search first. Seems like posting is easier.
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Old 12-12-2012, 10:18 AM   #11
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Originally Posted by Jerry Bransford View Post
If this were a forum for Mustang 5.0 or Camaro Z-28 enthusiasts, it'd be a universal yes that aftermarket air intakes can help improve performance for some engines... fairly substantially too since many air intakes like those are indeed restrictive.

But since this forum is for Wranglers whose air intakes were specifically designed to be non-restrictive, the answer is a resounding no to the question of if they will help with performance. As was well said above, the Wrangler's air intake is more than capable of easily flowing more air than the engine can consume at WOT (wide open throttle) and redline RPMs.

And the very last filter I would call 'good' is the K&N. In my strongest possible personal opinion, it is the worst filtering air filter of all that can be used in our Wranglers. It keeps as much dirt & harmful silica out of our engines as a screen door keeps dust out of the house during a Texas dust storm. I'd rather hit myself on the head with a hammer than run another K&N air filter in my Jeep as I stupidly did until 12-13 years ago when I figured out how much dirt it was letting into my engine. I ended up adding a prefilter on top of it trying to cut how much dirt was getting past it. One prefilter wasn't enough, I ended up having to run TWO prefilters until I could get rid of the K&N & go back to a paper element air filter.

This shows the two pre-filters, an Outerwears & an oiled foam Unifilter that I ended up adding trying to limit how much dirt that got past it and into my engine ...
k&n does not work unless it is maintained properly..this pic shows that the element is not oiled..when the element is not red from the k&n oil then it is past the time when it should have been serviced..jeeps may not need the extra flow that a k&n provides but it will allow more flow than a paper element
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Old 12-12-2012, 11:39 AM   #12
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This is probably the ONLY time I will ever disagree with Jerry, and it may just be because I'm stubborn and it hasn't cost me... yet

I have the K&N FIPK on mine, installed by the previous owner. I did notice it was allowing some dirt in (I'm pretty OCD about these things on new to me vehicles) but after servicing it, re-oiling it, and cleaning the throttle body. I have not seen any dirt (or oil) through it.
I will say my butt dyno seems to feel a difference over stock. In the many many jeeps Ive driven and test driven, mine seems to have a slightly quicker throttle response and mild benefits to the low end (over stock).

Enough to make it worth the purchase? I didn't necessarily say that, but enough to keep me from swapping back to stock for sure.
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Old 12-12-2012, 11:42 AM   #13
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one thing I DO recommend (never thought I would say this) is a throttle body spacer.
Not because its going to give you a million mpg or ANY noticeable increase in performance, but because it spaces out the TB sensors from the heat of the exhaust just enough to give them a more accurate reading. As cheap as they are, and easy as they are to install.. minaswell
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Old 12-12-2012, 11:50 AM   #14
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I have the K&N FIPK on mine, installed by the previous owner.

I will say my butt dyno seems to feel a difference over stock.
If it has been there since you bought the Jeep, I'm curious how you noticed a power increase over stock.
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Old 12-12-2012, 11:57 AM   #15
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Quote:
Originally Posted by Sherpa

If it has been there since you bought the Jeep, I'm curious how you noticed a power increase over stock.
Well he said he has test driven other stock jeeps. Maybe that's how
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Old 12-12-2012, 12:05 PM   #16
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k&n does not work unless it is maintained properly..this pic shows that the element is not oiled..when the element is not red from the k&n oil then it is past the time when it should have been serviced..
You couldn't have been more wrong about the state of my K&N air filter in that photo. I was absolutely anal about maintenance on that filter and I regularly used K&N oil on it each time after washing it. The filter was probably washed once a month and oiled afterward with K&N filter oil. With time, a K&N will turn that color and there is no washing procedure that will make it look new again. I even tried Simple Green at one point to try to make it look new again but it didn't help. In my above photo, you can see how everything was fresh & clean looking, the K&N filter and pre-filters had just been washed & was freshly oiled with the K&N oil.

One more tidbit (I know more about K&N filters than the average bear) about K&N air filters... they actually filter better after they have been used for a while & dirt has made its pores smaller. A freshly washed & oiled K&N air filter does not filter nearly as well as one that has been in use a period of time... up to a point of course. Fact.
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Old 12-12-2012, 12:12 PM   #17
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Well he said he has test driven other stock jeeps. Maybe that's how
Yes, I saw that (and I'm sure I should have mentioned it). But car-to-car variances are a fact of life... hence my question.

What this thread really needs is that dyno plot of someone testing a stock airbox verses a cold air intake on their 4.0L Jeep. Anybody know where to find it?
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Old 12-12-2012, 12:28 PM   #18
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You couldn't be more wrong about the state of my K&N air filter in that photo. I was absolutely anal about maintenance on that filter and regularly used K&N oil on it each time after washing it. The filter was probably washed once a month and oiled afterward with the K&N oil. With time, a K&B will turn that color and there is no washing procedure that will make it look new again. I even tried Simple Green to clean it. In my above photo, you can see how everything was fresh & clean looking, the K&N filter and pre-filters had just been washed & was freshly oiled with the K&N oil.

One more tidbit (I know more about K&N filters than the average bear) about K&N air filters... they actually filter better after they have been used for a while & dirt has made its pores smaller. A freshly washed & oiled K&N air filter does not filter nearly as well as one that has been in use a period of time... up to a point of course. Fact.
I have k&n's that are several years old.when they are washed with the k&n cleaner per the instructions and then oiled with the k&n oil per the instructions,even the old filters will be red and filter as they should..no doubt that using other cleaners or compressed air could damage them.also,using the proper oil makes a big difference
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Old 12-12-2012, 12:30 PM   #19
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Okay, I went and found the dyno thread (which you can see here in another forum). Here is one dyno chart showing the stock intake setup minus the horn on plot #11 compared to no intake at all--just an open throttle body:



Even if you try to ignore statistical error (which you shouldn't), we're talking a best-to-worst change of five HP. I seriously doubt anybody has an assometer which is so finely-tuned as to feel five extra horsepower.

Long story short, Jeep engineers did a great job designing the TJ's intake.
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Old 12-12-2012, 12:35 PM   #20
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Save your money for a needed upgrade!
The OEM air induction system is designed for the proper CFM air flow rate and also has a decent micron rated filter element.
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Old 12-12-2012, 12:38 PM   #21
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I have k&n's that are several years old.when they are washed with the k&n cleaner per the instructions and then oiled with the k&n oil per the instructions,even the old filters will be red and filter as they should..no doubt that using other cleaners or compressed air could damage them.also,using the proper oil makes a big difference
Uh huh. Funny that mine turned that color despite regular use of K&N's cleaner and oil yet you claim yours never did. I only mentioned my use of Simple Green after regular use of K&N's cleaner wouldn't restore the original color you claim yours have.

The bottom line is this... my K&N air filter in that photo was kept scrupulously clean and oiled using K&N's recommended cleaning procedure and products. Your claim it wasn't couldn't have been more wrong. Even having been kept clean and oiled using K&N's recommended products and procedures, it still passed more dirt than I could believe which is why I ended up adding the two pre-filters. You don't pay $$$ to add pre-filters if you don't notice an obvious filtration problem... which is why I'll NEVER run another K&N air filter... and I'm not even close to being alone with that feeling.
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Old 12-12-2012, 12:40 PM   #22
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good info! i think ill save my money too!
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Old 12-12-2012, 12:41 PM   #23
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If it has been there since you bought the Jeep, I'm curious how you noticed a power increase over stock.
It's all hearsay, I dont know the difference on MY jeep, just in other similar jeeps to mine. Honestly It could easily be other things my jeep has that would contribute to its performance. The difference is minimal, and not in the feel of HP but simply in throttle response.



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Okay, I went and found the dyno thread (which you can see here in another forum). Here is one dyno chart showing the stock intake setup minus the horn on plot #11 compared to no intake at all--just an open throttle body:



Even if you try to ignore statistical error (which you shouldn't), we're talking a best-to-worst change of five HP. I seriously doubt anybody has an assometer which is so finely-tuned as to feel five extra horsepower.

Long story short, Jeep engineers did a great job designing the TJ's intake.
which is why
Quote:
Enough to make it worth the purchase? I didn't necessarily say that, but enough to keep me from swapping back to stock for sure.
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Old 12-12-2012, 12:54 PM   #24
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Uh huh. Funny that mine turned that color despite regular use of K&N's cleaner and oil yet you claim yours never did. I only mentioned my use of Simple Green after regular use of K&N's cleaner wouldn't restore the original color you claim yours have.

The bottom line is this... my K&N air filter in that photo was kept scrupulously clean and oiled using K&N's recommended cleaning procedure and products. Your claim it wasn't couldn't have been more wrong. Even having been kept clean and oiled using K&N's recommended products and procedures, it still passed more dirt than I could believe which is why I ended up adding the two pre-filters. You don't pay $$$ to add pre-filters if you don't notice an obvious filtration problem... which is why I'll NEVER run another K&N air filter... and I'm not even close to being alone with that feeling.
yes,I claim
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Old 12-12-2012, 01:52 PM   #25
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Do not fall for the marketing hype about cold air intake. Worthless. And Jerry is right on about the filter. Thats why K & N says to let it go xxxxxx miles between service. It works better when caked with crud. Do what you want on your jeep...not on mine. Stock air intake.
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Old 12-12-2012, 06:22 PM   #26
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Do not fall for the marketing hype about cold air intake. Worthless. And Jerry is right on about the filter. Thats why K & N says to let it go xxxxxx miles between service. It works better when caked with crud. Do what you want on your jeep...not on mine. Stock air intake.
K&N does say something similar to that for street conditions..it is followed by CAUTION:extreme fine dust,agriculture or off-road use,will pull the oil from the element.Frequent re-oiling of the element may be required.Service with only k&n air filter cleaner and k&n air filter oil..
I do agree on the stock breather and that a paper filter is fine for a jeep as long as it is changed as needed.If someone feels that they need more flow then a k&n will provide that.most people will not feel a difference on a jeep because most don't need more flow than is already available.You will readily feel it on a harley
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Old 12-12-2012, 08:12 PM   #27
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The filter was probably washed once a month and oiled afterward with K&N filter oil.

they actually filter better after they have been used for a while & dirt has made its pores smaller.
Why would you clean it once a month if they filter better when they have been used for a while? Maybe your being "too anal". I've had one on my mustang for over 3 years now, never cleaned it, still flows fine, and not even the slightest dust in the intake. Sure its a mustang and does not drive offroad behind someone kicking up a giant dust storm.
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What this thread really needs is that dyno plot of someone testing a stock airbox verses a cold air intake on their 4.0L Jeep. Anybody know where to find it?
Somebody linked to my thread. This is the graph that the manufacturer will show.


If you can't make more power with an open throttle body, then there is no power to be gained with any intake or filter.
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Old 12-12-2012, 08:21 PM   #28
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Pos!
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Old 12-12-2012, 08:40 PM   #29
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So does the same go for a snorkel? Besides giving you the awesome ability to go scuba diving with your jeep
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Old 12-12-2012, 08:48 PM   #30
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If you get back to the basics of combustion, unless the engine has a super charger or turbo , simply opening the path for air and making it easier is not going to increase horsepower. The injection system would have to be modified to increase fuel also. If you could cram more air in then the mixture would be too lean...not good. Everything needs to be in balance. The entire cold air is also marketing hype. I think that got started because cars had a warm air flap to pull hot air off the exhaust manifold to keep the earlier systems from freezing the cis injection air lift plate. That was deemed restrictive and cold air is denser that hot air etc etc etc. But it's all a moot point on a jeep because as has been explained earlier the jeep air box is done correctly. But as I have stated before they also make and sell gold plated guitars and $300 dollar basketball shoes and neither is going to do a darn thing for my guitar playing or my basketball skills.

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