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Felt tube inside the air filter box


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Might be a little careful about removing it... I had an Austin Healey once and it had similar attachments to its dual Stromberg carbs. I was going to do away with them as they looked pretty ratty (old car), but, I knew a guy that was retired from the British Emabassy; their chief mechanic, and boy did he come in handy with that vehicle. Anyway, he said they (the felt wraps) were on the intakes to keep liquid water from being inhaled into the intakes. Turns out that the intake snorkel was level and pointed straight ahead. According to him that if following a car closely or a large splash occurred in front of the snorkels that water could enter the housing. The housing had drain holes, but, he said that it was possible that a large enough volume of water could enter and not drain rapidly enough out. The felt was used to absorb the liquid while allowing air to pass through, preventing hydraulic lock from happening in a cylinder...

I haven't even looked at my DJ's intake system, I'm not interested in CAI (I've been that direction on other cars and except for the sound, there was no other gains, hp or mpg, the car's computer regulates all of the input variables and more air doesn't buy you anything as the computer will make changes to the others to keep it in "trim") and it isn't anywhere near time for a filter change, so, I'm not real sure why Chrysler put those in, but, I do know why they were on my old Austin and I'm guessing Chrysler wouldn't have gone to the expense if they didn't know something... You could probably remove it and be good to go 99.8% of the time, but, if I had to guess, Chrysler put that on there for the other .2% and hydraulic cylinder lock does some really devastating damage to the rods, crank and block.

You might want to wait to see if the Chrysler Cares folks have some technical insight before removing them...

Edited by webslave
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Might be a little careful about removing it... I had an Austin Healey once and it had similar attachments to its dual Stromberg carbs. I was going to do away with them as they looked pretty ratty (old car), but, I knew a guy that was retired from the British Emabassy; their chief mechanic, and boy did he come in handy with that vehicle. Anyway, he said they (the felt wraps) were on the intakes to keep liquid water from being inhaled into the intakes. Turns out that the intake snorkel was level and pointed straight ahead. According to him that if following a car closely or a large splash occurred in front of the snorkels that water could enter the housing. The housing had drain holes, but, he said that it was possible that a large enough volume of water could enter and not drain rapidly enough out. The felt was used to absorb the liquid while allowing air to pass through, preventing hydraulic lock from happening in a cylinder...

I haven't even looked at my DJ's intake system, I'm not interested in CAI (I've been that direction on other cars and except for the sound, there was no other gains, hp or mpg, the car's computer regulates all of the input variables and more air doesn't buy you anything as the computer will make changes to the others to keep it in "trim") and it isn't anywhere near time for a filter change, so, I'm not real sure why Chrysler put those in, but, I do know why they were on my old Austin and I'm guessing Chrysler wouldn't have gone to the expense if they didn't know something... You could probably remove it and be good to go 99.8% of the time, but, if I had to guess, Chrysler put that on there for the other .2% and hydraulic cylinder lock does some really devastating damage to the rods, crank and block.

You might want to wait to see if the Chrysler Cares folks have some technical insight before removing them...

Wow, the stuff you learn on this forum!!!!

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The way engineers are focused on "quiet" nowadays, that could, indeed be the reason they are there or it could be that you just haven't run into the .2% of the reason it is there, yet. The same physics that are at work that allows the felt to keep water from being sucked in (slows the air velocity at the intake) would also keep the air's intake sound down. My Austin didn't have a quiet bone in its body, so, that wasn't the reason for them in that car LOL, but, I just wanted to issue a "caution" on arbitrarily removing things that don't to seem to have a reason for being there. With the cost of vehicles being so important to the manfacturers, they don't add things that don't have a good reason for being there. These cars are rather expensive to take much of a gamble with and I don't imagine that removing them has any benefits in performance or economy since the computer ultimately controls the amount of air that the engine uses and adjusts air/fuel ratio and speed (variable throttle bodies) accordingly. That ability is why the air filter change interval is so long now; the computer can adjust the air/fuel ratio so well that it can run quite efficiently on a partially clogged filter; 3 years or 30,000 miles now between filter changes, a far cry from the "good old days". I don't imagine a CAI unit has them, but, the CAI would be engineered to not need them...that doesn't infer that the stock air box doesn't, since from what I've been hearing, that airbox is "standard" across several versions of this engine and several models of cars with minor differences in the snorkels and piping and it may be that the DJ needs it and others don't due to snorkel design and that isn't something that a salesman or even service technician would know. There's a big difference in selling and servicing when compared to engineering systems and sub-systems.

I'll wait to see what the engineers say, if one of them replies, before I start removing things without a replacement device. I wouldn't remove the air box without adding some sort of replacement, i.e., a CAI unit, so, until I find out exactly why Chrysler put that in, I'll leave it there since it doesn't hurt anything and doesn't improve anything by removing it. Ultimately though, it is your gamble and any time we gamble it is up to each of us as to whether we roll the dice or ask for cards.

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I don`t to plan to remove the box and install CAI. I just want to increase the air flow for the engine for better fuel/air mixture,and that felt tube maybe help to stop the water to go tot he engine, but the main time it block the air flow as well. The air filter will work only partially, not in full capacity. Even with K&N filter in place. I will ask my mechanic about it as well. Main time I keep that tube in place. Maybe DodgeCare will provide the more information about that tube, or more members will provide their opinion as well

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I don`t to plan to remove the box and install CAI. I just want to increase the air flow for the engine for better fuel/air mixture,and that felt tube maybe help to stop the water to go tot he engine, but the main time it block the air flow as well. The air filter will work only partially, not in full capacity. Even with K&N filter in place. I will ask my mechanic about it as well. Main time I keep that tube in place. Maybe DodgeCare will provide the more information about that tube, or more members will provide their opinion as well

It wont do anything as Webslave stated.

Edited by jkeaton
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I guess i will keep the tube in place for the moment.I will try to get more information for that tube necessity in air box, because all my previous cars do not have that tube.Even on my previous dodge grand caravan -2008 do not have that tube.

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The tube it self long enough to cover almost the entire width of the box, so that will create the air restriction for the engine, the computer (ECU) must work harder to properly adjust the air/fuel mixture.If the tube is shorter or not there, then it more air will come to the engine and it will be better mix with fuel.

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I wouldn't start pulling stuff off if it were mine. A lot of Factory R&D goes into cars these days and I can assure you that everything was put there for a reason. Your computer is designed to run with this felt tube and by pulling it out you run the risk of throwing your computer out, or worse, you could void your warranty.

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Why dont you go ahead and remove it,. drive through a tankful of gas and see if it improves your mileage? I think it has been stated before, if the engineers who designed the car thought it would provide any benefit by not having it there, it would not be there. More air to the engine wont do anything for you without more fuel. The stoichiometric mixture for a gasoline engine is the ideal ratio (15:1) of air to fuel to allow all fuel to be burned with no excess air. The computer maintains the 15:1 ratio all the time regardless of how much or little air enters the intake manifold. That little felt piece does nothing to alter this.

Edited by jkeaton
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Why dont you go ahead and remove it,. drive through a tankful of gas and see if it improves your mileage? I think it has been stated before, if the engineers who designed the car thought it would provide any benefit by not having it there, it would not be there. More air to the engine wont do anything for you without more fuel. The stoichiometric mixture for a gasoline engine is the ideal ratio (15:1) of air to fuel to allow all fuel to be burned with no excess air. The computer maintains the 15:1 ratio all the time regardless of how much or little air enters the intake manifold. That little felt piece does nothing to alter this.

Exactly. A lot of us "old timers" built cars (yes, I built race cars in the late '60s and early '70s) and there were many things that "became legend" during those times. More air was one, but, even in those days, more air didn't do you any good until you re-jetted the carburetors or added additional carburetors to add the additional fuel to take advantage of it. To really take advantage of it, you needed to also alter the cam's duration for intake and exhaust, add a bigger exhaust system (headers, straight through pipes, low-flow mufflers, etc) to get rid of the exhaust so that you could get more air and fuel in quicker, etc.

Enter the modern day computer controlled systems. You can put more air in the system, but, it won't use it due to the variable venturi effect of the throttle body. The MAP will only allow the amount air to be used such that the "perfect" air/fuel mixture is maintained. Put more fuel in the mix, the computer will retard the engine and lean the injectors until it evens out. A new cam won't even buy you anything because the computer will again control spark (firing) and fuel (injectors) to maintain its "ideal".

CAI? Sure, it will make your car sound "meaner", but, no real gains in hp or mpg. CAT back exhaust? Again, more noise, the "meaner" sound, but, put it on a dyno and you've got nothing but sound effects. Anything a "shade tree" mechanic can do will do mostly zip for actual "performance"; the best improvements would be gained by turbo charging or putting a blower on it, but, that involves re-engineering the heads and block and re-programming of the computer to take advantage of the added compression ratios. I had a Jeep Commander with the Hemi and went that route just playing around. Had it dyno tested before and after. Zero change in hp at the wheels and zero change in long range fuel economy; in fact short range fuel economy suffered for awhile because "putting my foot in it" made it sound so much better...didn't go faster, it just sounded like it was. I actually, after about a year, put the stock air box and snorkel back on and re-installed the stock exhaust so that I had back the "peace and quiet" of the original Commander; without any performance enhancement the noise was irksome. I had forgotten all that I had learned building cars in the good old days.

Lesson learned? Yes you can tear the stock air cleaner off and install a CAI that will sound meaner, but, require more maintenance than the stock unit for no gains except noise. You can install a CAI for the added noise and possibly incur a short lifespan on the exhaust parts, but, again, no real gains. Until and unless you do something with the computer, it will regulate the "simple changes" so that there are no changes. Start messing with the computer and you can actually destroy the engine - check some of the diesel folks and their "extreme" tuners and the FEDS have stepped in so that those tuners are now regulated or banned for emission reasons. There are some things you can do for "improvement"; those of you without the larger brakes could upgrade the rotors and calipers. Those of you that don't like the ride can experiment with various spring packages and shocks, but, over-all "performance" is governed by the computer and the computer is quite capable of changing enough parameters that anything else you do will be either no gain, or engine damaging. The engineer's of today's vehicles do everything they can to "balance" hp, comfort and efficiency (mpg) and there really are no "miracle" cures that you can add off the shelf as a "bolt on" addition.

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I can't believe all of this fuss over a little felt tube. I took mine out because I had noticed it had fallen off anyways when I was changing my air filter. If it was that crucial, you would think it would have had a better means of securing it in place. I don't know how you would ever suck water into the air box if the inlet is at the top of the bumper, 3-4 ft above ground. If you're driving in that deep of water, you would have bigger fish to fry anyways.

To each their own though...

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My 12' Avenger had the exact same felt liner tube, it's there to reduce noise, I removed mine in that car & in my current 13' journey as well as added a k&n drop in filter. It produced a lil more growl. I'm wondering if the new k&n kit for the Avenger will fit on the Journey?

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My 12' Avenger had the exact same felt liner tube, it's there to reduce noise, I removed mine in that car & in my current 13' journey as well as added a k&n drop in filter. It produced a lil more growl. I'm wondering if the new k&n kit for the Avenger will fit on the Journey?

Then, in the DJ, it may be a noise eliminator working in conjunction with the air box resonator to keep noise levels down. The DJ, even the R/T model, is a passenger car (CUV) and with all the UConnect features, the engineers were/are concerned with keeping noise levels down to make the "sound" better in the cabin area. The point though, still is, that removing it won't gain anything. What little restriction it has is easily compensated by the computer and computers don't "work harder"...I'm retired IT (Systems Integrator) and believe me, those CPU units in these cars are loafing. They are designed to control fuel air ratio in milliseconds and all the air in the world available to the system won't affect the ratio delivered by the computer. As I mentioned earlier, the only way you can achieve a gain in either hp or efficiency is to force more of that "perfect mixture" into the cylinders and that can only be achieved by a Roots style blower or turbo charger (that's how the Ecoboost works) and not by simply providing a bigger pipe for the air. It will only use what it needs no matter how much is available.

If you want to remove it, feel free. Even if it is there for water abatement (and water being splashed at the front of your car at 70 mph can work its way into a straight snorkel) the odds of that happening are probably small in most circumstances, but, the engineers tend to try to protect against even small hazards if they know about them in advance. Most likely it is there primarily for noise abatement and all you'll do is add more noise to the operation of your DJ. I like mine quiet, so, I'll leave mine on; but, that's just me. I'm old enough to be past the "yahoo, listen to me" noise in my cars if it doesn't provide any performance improvement. YMMV

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Really so your saying that a freer flowing air filter makes no more power? All these intake companies that dyno their products are lying? There's always a lil play room with the ecu and more air flowing thru the intake, not much maybe 10 hp but that works for me! According to k&n and a few dyno the drop in filter gained 7 hp, the full piped intake by mopar performance was said to gain 10. As far as water in the intake most models of vehicles I've owned (which was many) never had any felt tunes in them! The whole front mount snorkel intake has been in Japanese cars for many many years! I've had true cold air intakes in many of my cars & trucks with no water issues and they are down low! So no worries about it up that high! Plus the k&n has a oiled filter, you know what they say about oil & water! I've had a fully bolted speed3 that laid down 305 hp and 400+ ftlbs of tq so I know all about for forced induction. A intake on that car alone gained 25 whp.

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Really so your saying that a freer flowing air filter makes no more power? All these intake companies that dyno their products are lying? There's always a lil play room with the ecu and more air flowing thru the intake, not much maybe 10 hp but that works for me! According to k&n and a few dyno the drop in filter gained 7 hp, the full piped intake by mopar performance was said to gain 10. As far as water in the intake most models of vehicles I've owned (which was many) never had any felt tunes in them! The whole front mount snorkel intake has been in Japanese cars for many many years! I've had true cold air intakes in many of my cars & trucks with no water issues and they are down low! So no worries about it up that high! Plus the k&n has a oiled filter, you know what they say about oil & water! I've had a fully bolted speed3 that laid down 305 hp and 400+ ftlbs of tq so I know all about for forced induction. A intake on that car alone gained 25 whp.

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Really so your saying that a freer flowing air filter makes no more power? All these intake companies that dyno their products are lying? There's always a lil play room with the ecu and more air flowing thru the intake, not much maybe 10 hp but that works for me! According to k&n and a few dyno the drop in filter gained 7 hp, the full piped intake by mopar performance was said to gain 10. As far as water in the intake most models of vehicles I've owned (which was many) never had any felt tunes in them! The whole front mount snorkel intake has been in Japanese cars for many many years! I've had true cold air intakes in many of my cars & trucks with no water issues and they are down low! So no worries about it up that high! Plus the k&n has a oiled filter, you know what they say about oil & water! I've had a fully bolted speed3 that laid down 305 hp and 400+ ftlbs of tq so I know all about for forced induction. A intake on that car alone gained 25 whp.

Yep, they are lying. But for $300 +, they sure do souond cool.

Edited by jkeaton
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If it were that easy, every manufacturer would include a CAI as stock; they are always looking for ways to boost HP without it costing them anything and a CAI is much cheaper to manufacture than the stock airbox, plumbing and resonators. Your 6-25 HP increases are statistically insignificant (numerically to a statistician) as "background noise" and well within the standard deviation of error based on friction at the wheels, humidity and temperature along with mechanical losses and gains of the dyno itself. Like I said, I used to build cars that developed far more HP and were much more sensitive to input changes. We went so far as to make sure each piston, wrist pin and crank weighed the same (balancing) and coated the piston walls with architectural dye (blue printing) to determine ring scrub...

If it were so simple (the CAI), Ford certainly wouldn't have invested the millions necessary to develop the Ecoboost turbo system. I'll quit; the CAI myth has been debunked by many ASE groups along with the above Myth Busters episode. It produces growl and that's about it. Most of the CAI units actually duct more engine compartment heat into the system (they are open and drafty as all get out on top) than the stock sealed unit that snorkles cold air from ahead of the radiator into the system that is predominately thin plastic (less of a heat transfer medium) than the heavy pipe (absorbs and holds engine bay heat) and thin stamped metal (a radiator of engine heat) that the box is made of in CAI systems. Do you honestly think that BMW, Mazda, Mercedes, etc. would pass up a means of adding 25 or more HP by leaving more expensive equipment off and substituting less expensive components?

End of my involvement...it's your money to spend any way you deem appropriate.

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Really? My intake on my speed was a Mazdaspeed brand part genius. And I have seen many dyno's online with that 25 whp gain! And Ford racing has their own intakes, they come stock on the high end mustangs! Sorry but you put a shitty flowing air filter or one that doesn't flow enough against a better flowing one with higher flow it's gonna gain some power! Granted nothing near as much as a turbo car. That YouTube video was a joke! They didn't even give proper ecu adjustment curves, they just slapped the next one on! And really no filter at all flows as much as the stock intake? Right!

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Really? My intake on my speed was a Mazdaspeed brand part genius. And I have seen many dyno's online with that 25 whp gain! And Ford racing has their own intakes, they come stock on the high end mustangs! Sorry but you put a shitty flowing air filter or one that doesn't flow enough against a better flowing one with higher flow it's gonna gain some power! Granted nothing near as much as a turbo car. That YouTube video was a joke! They didn't even give proper ecu adjustment curves, they just slapped the next one on! And really no filter at all flows as much as the stock intake? Right!

As webslave says,. it's your money. Do with it what you will. Facts and statistics dont back it up though.ECU curves? Unless your custom programming your ECU along with your CAI, the ECU corrects for any excess air flow and negates any positive impact a CAI may have. Grant you I have one on my 1995 Z71, but only cause it makes my TBI sound like 4BBL at WOT.....lol

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